摘要:

INTER-LABORATORY NOTE Determination of inorganic mercury in biological tissues by cold vapor atomic absorption spectrometry following tetramethylammonium hydroxide solubilization{ Guanhong Tao{, Scott N. Willie* and Ralph E. Sturgeon Institute for National Measurement Standards, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R9 Received 3rd August 1999, Accepted 21st September 1999 A rapid and simple method for the quantiÆcation of inorganic and total mercury in biological tissues using Øow injection cold vapor generation atomic absorption spectrometry is presented.Samples were solubilized using tetramethylammonium hydroxide. The inorganic Hg was released by on-line addition of L-cysteine and then reduced to metallic Hg by SnCl2. The detection limit for inorganic mercury was 0.1 mg l21 and the precision of determination was better than 2% (RSD) at 20 mg l21. The proposed method was validated by the analyses of a suite of certiÆed marine biological reference materials, DORM-2 (dogÆsh muscle), DOLT-2 (dogÆsh liver) and TORT-2 (lobster hepatopancreas).Introduction It is well known that the toxicity of mercury is highly dependent on its speciÆc chemical form; organomercury compounds have been recognized for many years as being more toxic than inorganic species. Analyses of samples for total mercury only are therefore no longer completely acceptable because they provide only partial information about their impact on human health and the environment. As a consequence, considerable effort and progress have been made in the development of techniques which are capable of separating and identifying the various mercury species.1±3 However, complete separation may not be required as simple differentiation between inorganic and total mercury may be sufÆcient. Tetramethylammonium hydroxide (TMAH) has been used as a `tissue solubilizer' for various biological samples prior to analysis for major and minor inorganic elements by Øame AAS,4±7 furnace AAS8±11 and ICP-AES.12,13 TMAH has also been used for the rapid sample preparation of biological tissues prior to mercury speciation analysis.14±16 Jimenez and Sturgeon14 successfully determined inorganic and methylmercury species in biological tissues after TMAH solubilization using ethylation and GC with furnace atomization plasma emission spectrometric detection.Tseng et al.15 also utilized this sample preparation method in their recent work on mercury speciation in biological samples using GCCVAAS. Willie et al.16 reported a rapid method for the determination of total and inorganic mercury in biological tissues using electrothermal vaporization ICP-MS. Inorganic and total mercury in the TMAH phase were selectively introduced to the plasma by means of chemical modiÆcation.Recently, Tao et al.17 reported a simple and rapid method for the determination of total mercury in biological samples following solubilization with TMAH.Organically bound mercury was cleaved and converted into inorganic mercury by on-line addition of KMnO4. The decomposed mercury, together with inorganic mercury originally present, was determined by Øow injection cold vapor atomic absorption spectrometry (CVAAS) after reduction to elemental mercury vapor using NaBH4. In this paper, a rapid and simple method is presented for the determination of inorganic mercury in biological samples using CVAAS detection.Experimental Instrumentation A Perkin-Elmer Model 4100ZL atomic absorption spectrometer was used, equipped with a Perkin-Elmer FIAS-400 Øow injection system and an AS-90 autosampler. A Perkin-Elmer mercury electrodeless discharge lamp was operated at 180 mA. The mercury absorbance was measured at 253.6 nm with a 0.7 nm spectral bandpass. A schematic diagram of the Øow injection manifold is shown in a previous paper.17 For this work the NaBH4 and KMnO4 were replaced with 1% SnCl2 and 0.5% L-cysteine, respectively. The Øow injection program and the sample, reagent and argon stripping gas Øow rates remained the same.Reagents and standard solutions All chemicals were of analytical-reagent grade unless speciÆed otherwise. A commercial ultra-pure water system (Barnstead/ Thermolyne, Dubuque, IA, USA) consisting of a reverse osmosis unit and a mixed ion-exchanger bed was used to produce high purity water. TMAH (30% in methanol) (Aldrich, Milwaukee, WI, USA) was used to solubilize the samples.SnCl2 solution (1% m/v) was prepared daily from the SnCl2 stock standard solution (20% m/v) after appropriate dilution with water. The latter was prepared in 10% v/v HCl and purged with argon at ca. 80 ml min21 overnight while being stirred. An antifoaming agent (defoamer product No. 4528R158 Home Hardware Stores, Burford, Ontario, Canada), obtained in the form of a household carpet cleaning additive, was diluted 10-fold (w/v) before use.17 A 1 ml volume of the diluted antifoaming agent was added to 200 ml of the SnCl2 solution.L-Cysteine {Canadian Crown Copyright. {On leave from the Flow Injection Analysis Research Center, Department Chemistry, Northeastern University, Shenyang, China. J. Anal. At. Spectrom., 1999, 14, 1929±1931 1929 This journal is # The Royal Society of Chemistry 1999(0.5%) was prepared daily in water, HCl (0.1 mol l21) was used as carrier. Inorganic and organic mercury stock standard solutions were prepared as described previously.17 Working standard solutions were prepared daily by serial dilution with high purity water. The Ænal solutions contain 4% v/v TMAH.National Research Council of Canada (NRCC) (Ottawa, ON, Canada) certiÆed reference materials DORM-2 (dogÆsh Øesh), DOLT-2 (dogÆsh liver) and TORT-2 (lobster hepatopancreas) were used to assess the accuracy of the method. Sample preparation Nominal 0.25 g sub-samples of biological tissue reference material were weighed into 50 ml pre-cleaned screw-capped polypropylene bottles and 4 ml of TMAH added.Following the reaction of the tissue with the TMAH for approximately 5 min, high purity water was added to bring the volume to 25.0 ml (mass basis). Blanks were processed through an identical procedure. The resulting samples were ready to be analyzed in 30 min. Procedure For inorganic mercury determinations, sample was injected into the carrier stream (0.1 mol l21 HCl) and then merged with L-cysteine and SnCl2 solutions in sequence in the chemifold.The release of protein-bound inorganic mercury by L-cysteine occurred in the reaction coil L1 and mercury vapor was generated in reaction coil L2. The mercury vapor formed was separated in the gas±liquid separator (GLS) and transferred by a Øow of argon carrier into the quartz cell for measurement. The procedure used to determine inorganic mercury resulted in a different sensitivity from that of the total mercury procedure,17 necessitating the construction of separate calibration curves using HgII standards for each method.QuantiÆcation was achieved by comparison of the response against the relevant peak height calibration curve. Results and discussion Compared with conventional sample preparation techniques for mercury speciation,18,19 this method is relatively simple, fast and less prone to contamination and analyte loss. At Ærst the resulting sample `digest' is neither clear nor colorless; however, on standing, the digest becomes less cloudy in appearance.No difference was found in the Ænal results for samples prepared 30 min or 3 months prior to determination and it has been reported that such TMAH digested solutions are stable in the usual laboratory environment for at least 1 year after preparation.14 Inorganic mercury determination Following solubilization of biological samples in TMAH, inorganic mercury may still be bound to proteins or other molecules and not be completely reduced to elemental mercury by SnCl2.3,20 Various methods have been reported to liberate mercury from its bound ligands, including addition of NaCl, HNO3 and K2Cr2O7,21 L-cysteine,18,22 CuCl23 or microwave heating.15 In this study, all the above mentioned methods were tested. It was found that the addition of L-cysteine was the most effective and simplest way to release the mercury from ligands present.The released mercury probably forms a thiol complex with L-cysteine, which can be easily reduced to elemental Hg by SnCl2.18,22,23 Addition of L-cysteine was conveniently achieved by on-line merging of the reagent with the TMAH digest.Fig. 1 shows the effect of L-cysteine concentration on the recovery of inorganic mercury in NRCC certiÆed reference material DOLT-2. Without L-cysteine, only ca. 20% of the inorganic mercury could be detected by CVAAS. Increasing the concentration of L-cysteine resulted in an increased recovery, satisfactory results being obtained when 0.4% or more L-cysteine was used.Therefore, 0.5% L-cysteine was chosen for further study. Similar results were obtained for the other two certiÆed reference materials, DORM-2 and TORT-2. Hydrochloric acid was added to the L-cysteine solution to provide favorable acidity for the release of protein bound mercury. The effect of hydrochloric acid concentration on the efÆcacy of the process is shown in Fig. 2. The reaction between L-cysteine and bound mercury was very fast, and a short 15 cm length of tubing (L1) to permit mixing of the reagents was sufÆcient to ensure complete release of mercury. Figures of merit Both inorganic and total mercury analysis systems were calibrated with a series of HgII standards having concentrations ranging up to 30 mg l21 . Because different chemicals, particularly reducing agents, were used in both procedures, their analytical sensitivities were different.It was therefore necessary to prepare two separate calibration curves for inorganic and total mercury determination. Detection limits were 0.2 mg l21 for inorganic mercury compared with 0.1 mg l21 for total mercury determination, based on 3s of blank TMAH solutions. The precision of determination was better than 2% (relative standard deviation) at a level of 20 mg l21 Hg (n~11). The sample throughput was approximately 100 h21, i.e., about 15 samples per hour for the quantiÆcation of inorganic mercury with triplicate determination.Fig. 1 Effect of L-cysteine concentration on the recovery of inorganic mercury in DOLT-2. Fig. 2 Effect of HCl concentration on the release of inorganic mercury. 1930 J. Anal. At. Spectrom., 1999, 14, 1929±1931Analytical results The accuracy of the method was evaluated by analyzing a suite of marine biological certiÆed reference materials. The results are summarized in Table 1. DORM-2 (dogÆsh Øesh material), DOLT-2 (dogÆsh liver tissue) and TORT-2 (lobster hepatopancreas) are all certiÆed for total and methylmercury content.The determined values for inorganic mercury agree with the difference between the certiÆed total and methyl mercury contents and with earlier published results.17 Acknowledgements G.T. thanks the NRCC for Ænancial support while in Canada. References 1 W. Baeyens, Trends Anal. Chem., 1992, 11, 245. 2 Analysis of Contaminants in Edible Aquatic Resources, ed. J.W. Kiceniuk and S. Ray, VCH, New York, 1994, pp. 175±204. 3 R. Puk and J. H. Weber, Appl. Organomet. Chem., 1994, 8, 293. 4 A. J. Jackson, L. M. Michael and H. J. Schumacher, Anal. Chem., 1972, 44, 1064. 5 L. Murthy, E. E. Menden, P. M. Eller and H. G. Pertering, Anal. Biochem., 1973, 53, 365. 6 P. D. Kaplan and M. Blackstone, Arch. Environ. Health, 1973, 27, 387. 7 Y. Zhou, M. K. Wong, L. L. Koh and Y. C. Wee, Talanta, 1996, 41, 1061. 8 S. B. Gross and E. S. Parkinson, At.Absorpt. Newsl., 1974, 13, 107. 9 F. Alt and H. Massmann, Spectrochim. Acta, Part B, 1978, 33, 337. 10 Y.-X. Tan, W. D. Marshall and J.-S. Blais, Analyst, 1996, 121, 483. 11 Y.-X. Tan and W. D. Marshall, Analyst, 1997, 122, 13. 12 J. L. M. De Boer and F. L. M. J. Maessen, Spectrochim. Acta, Part B, 1983, 38, 739. 13 T. Uchida, H. Isoyama, K. Yamada, K. Oguchi and G. Nakagawa, Anal. Chim. Acta, 1992, 256, 277. 14 M. S. Jimenez and R. E. Sturgeon, J. Anal. At. Spectrom., 1997, 12, 597. 15 C.-M. Tseng, A. De Diego, F. M. Martin, D. Amouroux and O. F. X. Donard, J. Anal. At. Spectrom., 1997, 12, 743. 16 S. N. Willie, D. C. Gregoire and R. E. Sturgeon, Analyst, 1997, 122, 751. 17 G.-H Tao, S. N. Willie and R. E. Sturgeon, Analyst, 1998, 123, 1215. 18 L. Magos and T. W. Clarkson, J. Assoc. Off. Anal. Chem., 1972, 55, 966. 19 G. Westo»o» , Acta Chem. Scand., 1967, 21, 1790. 20 C. Vandecasteele and C. B. Block, Modern Methods for Trace Element Determination, Wiley, Chichester, 1993, ch. 5. 21 C. E. Oda and J. D., Ingle Jr., Anal. Chem., 1981, 53, 2305. 22 J. Gutierrez, H. Travieso and M. A. Pubillones, Water Air Soil Pollut., 1993, 68, 315. 23 T. Tomiyasu, A. Nagano, H. Sakamoto and N. Yonehara, Anal. Sci., 1996, 12, 477. Paper 9/06313G Table 1 Analytical results for certiÆed reference materials (mg g21) CertiÆeda Measuredb Sample Methyl mercury Total mercury inorganic mercury DOLT-2 0.693°0.053 2.14°0.28 1.34°0.041 DORM-2 4.47°0.32 4.64°0.26 0.22°0.014 TORT-2 0.152°0.013 0.27°0.06 0.13°0.010 aUncertainty reported as 95% conÆdence interval. bUncertainty reported as standard deviation (n~3). J. Anal. At. Spectrom., 1999, 14, 1929±1931 1931

ISSN:0267-9477    

DOI:10.1039/a906313g

出版商:RSC    

年代:1999

数据来源: RSC

摘要:

COMMUNICATION Improving sensitivity for CE-ICP-MS using multicapillary parallel separation{ Vahid Majidi,*a Johanna Qvarnstro»m,b Qiang Tu,bWolfgang Frechb and Yngvar Thomassenc aLos Alamos National Laboratory, Los Alamos, New Mexico 87545, USA bDepartment of Chemistry, Analytical Chemistry, Umea University, 901 87 Umea , Sweden cNational Institute of Occupational Health, P.O. Box 8149DEP, N-0033 Oslo, Norway Received 27th July 1999, Accepted 15th September 1999 A multicapillary, capillary electrophoresis inductively coupled plasma mass spectrometry interface is described.This interface allows for higher sample loading to improve the overall sensitivity and analyte detection limits without sacriÆcing the separation efÆciencies. The results obtained with this parallel system are presented for a cross Øow nebulizer. A comparison of single capillary electrophoresis for both DIHEN and cross Øow nebulizers is presented. Introduction The strong need to identify speciÆc compounds and distribution of elements has increased the use of separation technologies with spectroscopic detection.1±4 SpeciÆcally, capillary electrophoresis has become the method of choice for separation when speciation applications are considered.5,6 Because of the lack of a stationary phase and with an operational pH range well within the stability region of many species, CE is one of the few technologies that seem to preserve the original chemical information during the separation stage.In spite of Øow rate incompatibilities and limited sample volumes, inductively coupled plasma mass spectrometry has emerged as the method of choice for detection of metalloids and metal-containing species separated by CE.7±9 The major drawback, when using CE for chemical speciation, is the limited amount of sample utilized during the analysis. Because the sample loading in CE is typically less than 100 nl, even with the low detection limit of ICP-MS, the analyte concentration within the sample must be relatively large (w10 mg l21).9 Although this may not pose a great problem for chemical speciation in many environmental samples, evaluation of metal species in clinical samples at physiological concentrations is not practical.One approach to alleviate the stringent requirement for higher analyte concentration is to use more efÆcient nebulization schemes for sample introduction into ICP. Several researchers have utilized high efÆciency nebulizers for plasma based applications.10±12 In most instances a gain of 10±100 can easily be obtained when high efÆciency nebulization is employed. Nonetheless, this gain is still at least an order of magnitude lower than what is really needed for clinical applications (e.g., measurement of manganese bound to transferrin).Introduction of larger sample volumes into CE is not a viable solution as peak broadening and poor resolution due to column overloading deteriorates the quality of information gained through separation.Using larger diameter capillaries can yield higher column loading; however, at best a factor for 2±5 larger sample amounts are usable before problems associated with larger column diameters fully manifest themselves. The main problem with large column diameters is the need for large separation currents, which will cause heating of the run buffer, in turn leading to poor separation efÆciencies. Therefore, column loading cannot be increased effectively through the use of a single capillary, hence a multicapillary system seems to provide the appropriate solution for sample loading.Currently, monolithic multicapillaries are commercially available. Unfortunately these systems are not appropriate for CE applications because the uniformity of internal diameter for each individual capillary cannot be veriÆed throughout the length of the column (electron micrographs show signiÆcant capillary±capillary variation of internal diameter).Furthermore, because of monolithic construction the heat transfer from each capillary to the ambient environment is extremely poor and subsequently the separation conditions are not constant throughout all capillaries (i.e., the capillaries at the center of the pack run hotter than the capillaries on the outer perimeter). In this paper we describe a unique approach which takes advantage of a parallel separation scheme to realistically improve the analytical sensitivity and detection limits.Several individual capillaries with identical internal diameters and lengths are placed in a loose bundle. Because the capillaries are not physically in contact throughout the bundle, the heat transfer to ambient atmosphere is not hindered. The terminal end of these capillaries (cathodic end) is placed into a cross Øow nebulizer. For comparison a direct injection high efÆciency nebulizer (DIHEN) is also used for single capillary separation to provide high efÆciency nebulization without the need for a spray chamber. Therefore, nearly 100% sample utilization is realized without adverse effects derived from the spray chamber (i.e., analyte±chamber interactions, band broadening, sample loss, etc.).Experimental Separation capillaries consisted of 75.0 cm long fused silica columns (from the same spool) with an internal diameter of 75 mm and an external diameter of 375 mm (Polymicro Technologies, Inc., Phoenix, AZ, USA).Prior to their use, capillaries were conditioned by Øushing with 0.1 M NaOH for 30 min, followed by washing with water and buffer. The CE system was designed in-house using a Spellman CZE1000, (Spellman High Voltage Electronics, Hauppauge, NY, USA) {US Government Copyright. J. Anal. At. Spectrom., 1999, 14, 1933±1935 1933 This journal is # The Royal Society of Chemistry 1999power supply. The power supply can be operated in voltage (30 kV maximum) or current controlled (300 mA maximum) mode.The CE-ICP-MS interface was assembled according to the procedure published previously.13 The CE performance was tested for one and several parallel capillaries using a number of cations. A cross Øow nebulizer connected to a double-pass Scott spray chamber (provided with the ICP-MS instrument) was used for most experiments. A DIHEN nebulizer (J. E. Meinhard Associates, Inc., Santa Ana, CA, USA) was used to assess the sensitivity improvements for single capillary CE separation.The test sample contained 100 mg l21 each of La, Mn, Ba and Cs in Milli-Q (Millipore, Bedford, MA, USA) water, unless otherwise noted. During sample introduction the nebulizer gas Øow was set to 0.4 l min21 and the samples were introduced electrokinetically for 10 s at 21 kV. The length of the capillaries was adjusted so that each cathodic terminal (at the nebulizer) and each anodic end (sample cup) were at the same position.Furthermore, both ends of the capillary bundle were held at the same elevation to minimize the Øow through the capillaries because of pressure difference. The position of the capillaries was not changed during sample introduction; instead, the sample cups were moved for injection and for introduction of the run buffer. For each run sample cups were Ælled with a fresh, 100 mg l21 mixture of cations. The buffer solution was replenished at least every third run. Between every run, with the multi-capillary setup, buffer was Øushed (0.25 ml min21) through the columns for 1 min.The total volume of each capillary was 3.3 ml. After each day the capillaries were Øushed with and placed in water and in the morning of the following day they were washed with 0.1M NaOH, water and buffer as described above. The separation buffer was a 20 mM ammonium acetate solution with a pH of 6.5. This solution was made fresh daily or every other day. The buffer was Æltered through a 0.45 mm Ælter and de-gassed in an ultrasonic bath for 10 min.The sample solution was made up daily in acid washed bottles from a 1 mg l21 stock solution. The quadrupole-based ICP-MS used in these studies was a Perkin-Elmer ELAN-6000 (SCIEX, Thornhill, Ontario, Canada). During the operation of CE-ICP-MS the nebulizer gas (Ar) Øow was set at the optimized value of 1.05 l min21 and the sheath buffer Øow rate was 0.4 ml min21. The voltage was set to 21 kV and the current was about 30 mA for each capillary.One MS scan, measuring all elements using the peak hopping mode, was completed within 1.4 s. Results and discussion It is important to emphasize that the current work is preliminary in nature and is designed to evaluate the potential use of a parallel separation scheme for high sample loading resulting in low detection limits. As such, at this stage, we did not attempt to use massively parallel bundles to maximize the loading. Because of the restricted inlet on DIHEN only one capillary with an external diameter of 375 mm could Æt within the nebulizer.Therefore, a cross-Øow nebulizer was used to evaluate the multicapillary concept. However, in future work, capillaries with internal diameter of 75 mm and external diameter of 150 mm will be used to maximize the sample loading, speciÆcally for use with DIHEN. Using the 150 mm external diameter capillaries, as many as eleven parallel columns may be used for separation.The schematic diagram of parallel capillary interface with a cross-Øow nebulizer is shown in Fig. 1. To illustrate the system performance and establish a benchmark, the CE-ICP-MS was initially set up with a single capillary using a cross-Øow nebulizer. After sample injection, the analytes were separated and introduced into the ICPMS. All four analytes were separated and are illustrated in Fig. 2. The migration time from the capillary for all analytes is between 3 and 5 min.Although the concentration of all elements is the same, the individual response of the ICP-MS is not identical. Subsequently, Cs and Ba have the largest peak heights and peak areas, while smaller peaks are obtained for Mn and La. The cations migrate in the capillary in the order of Cs, Ba, Mn and La. The size and charge of the cation±acetate complex formed during the separation dictate this migration order. To establish a benchmark, we may consider the migration time and peak height for Cs, which are 3.2 min and 330 000 cps, respectively.The results for an injection of the sample on a three-capillary parallel separation device are shown in Fig. 3. Several points of interest can be highlighted for this separation. First, the migration time and the migration orders are similar, within experimental error, for three parallel capillaries and the single Fig. 1 Schematic diagram for multicapillary interface to a nebulizer. Fig. 2 Separation and detection of four cations with a single capillary CE-ICP-MS.Fig. 3 Separation and detection of four cations with a multicapillary CE-ICP-MS. 1934 J. Anal. At. Spectrom., 1999, 14, 1933±1935capillary system. Second, the signal intensity for all analytes is higher when parallel capillaries are used. More speciÆcally, considering our benchmark, Cs, for the parallel separation scheme the migration time and signal intensity are 3.2 min and 1 000 000 cps, respectively. The fact that only a single peak is observed for each element and that the signal intensity is three times larger than the single capillary clearly indicate the successful operation of this device.Although all capillaries were taken from the same spool and were conditioned in the same manner, occasionally the migration time may be different amongst individual capillaries. Reconditioning and careful adjustment of capillaries to exactly the same height in the sample cup is essential. Furthermore, to verify that each capillary behaves nearly the same as all other capillaries, the run current for each capillary was measured in order to Ænd columns that would match very closely (this procedure took only a few minutes for each capillary tested).With three such identiÆed capillaries it was possible to obtain peaks with identical retention times for the elements studied. However, lack of attention to the above mentioned operational parameters will yield poor separation conditions and ultimately lead to broadened peaks or peak splitting. This manifestation of separation artifacts in unmatched capillaries is shown in Fig. 4. In this Ægure, we can note that two of the capillaries are functioning in an identical manner, while the third capillary has slightly different separation characteristics. Nonetheless, the peak areas of all runs were constant, regardless of the artifacts. Good separation results were obtained when the sheath Øow rate of the make-up buffer was at 0.4 ml min21.The advantages of using a DIHEN are clearly shown in Fig. 5. In this experiment, a 100 mg l21 solution of Cs, Ba and La mixture is separated on a 75 mm internal diameter CE column. The optimized nebulizer sheath Øow rate and the Ar Øow rate were experimentally determined to be 10 ml min21 and 0.25 l min21, respectively. Under these conditions a slight negative pressure at the cathodic end of the capillary results in shorter migration times (due to a slight laminar Øow).Therefore, to minimize this laminar Øow caused by aspiration during the sample injection period, the makeup buffer sheath Øow rate was increased to 100 ml min21 and the nebulizer Ar Øow rate was intentionally stopped. From the Ærst glance one can note that the peaks are much more symmetrical when DIHEN is used because band broadening due to analyte residence time in the spray chamber is eliminated. Second, while La gave a broad peak when the spray chamber was used, with DIHEN a sharp and symmetrical peak is obtained.This indicates that La strongly interacts with the spray chamber walls and, as such, the CE resolution for La analysis will be adversely affected. Lastly, because of the lower amount of make up buffer used during the separation, the background counts are extremely small for the analytes studied. This lower background translated into a better signal to noise ratio and ultimately results in lower detection limits. A comparison of identical samples run on both DIHEN and cross-Øow nebulizer show that DIHEN is twice as sensitive.The signal-to-noise ratio is also better by a factor of two for DIHEN (over crossØow). Future work will be speciÆcally aimed at using multicapillary separation with DIHEN nebulizers. Conclusion We have clearly demonstrated in this work that use of parallel separation schemes with capillary electrophoresis and ICP-MS detection can enhance the sensitivity for a given analysis.When comparing a multicapillary with a single capillary run the peak area was increased proportionally to the number of capillaries. This was also true for the peak height with completely overlapping peaks. With three capillaries and a cross-Øow nebulizer the detection limits (36noise) for Cs, Ba, Mn and La are of 33, 100, 100 and 500 ng l21, respectively. The concept of multicapillary electrophoresis could also be applied to other interfaces. Acknowledgements One of the authors (V. M.) received funding from ADAPT program at Los Alamos National Laboratory for travel to Norway and Sweden to initiate this collaborative work. References 1 S. C. K. Shum, H.-M. Pang and R. S. Houk, Anal. Chem., 1992, 64, 2444. 2 H. M. Crews, P. A. Clarke, D. J. Lewis, L. M. Owen, P. R. Strutt and A. Izquierdo, J. Anal. At. Spectrom., 1996, 11, 1177. 3 R. Lobinski, Appl. Spectrosc., 1997, 51, 260A. 4 M. K. Donais, Spectroscopy, 1998, 13, 30. 5 M. E. Swartz, J. Liq. Chromatogr., 1991, 14, 923. 6 M. P. Richards, J. H. Beattie and R. Self, J. Liq. Chromatogr., 1993, 16, 2113. 7 J. W. Olesik, J. A. Kinzer and S. V. Olesik, Anal. Chem., 1997, 67, 1. 8 Q. Lu, S. M. Bird and R. M. Barnes, Anal. Chem., 1997, 67, 2949. 9 V. Majidi and N. J. Miller-Ihli, Analyst, 1998, 123, 809. 10 P. W. Kirlew and J. A. Caruso, Appl. Spectrosc., 1998, 52, 770. 11 P. W. Kirlew, M. T. M. Castillano and J. A. Caruso, Spectrochim. Acta, Part B, 1998, 53, 221. 12 S. A. Baker and N. J. Miller-Ihli, Appl. Spectrosc., 1999, 53, 471. 13 V. Majidi and N. J. Miller-Ihli, Analyst, 1998, 123, 803. Paper 9/06100B Fig. 4 Separation and detection of four cations with a poorly matched multicapillary CE-ICP-MS. Fig. 5 Separation and detection of three cations with a DIHEN nebulizer CE-ICP-MS. J. Anal. At. Spectrom., 1999, 14, 1933±1935 1935

ISSN:0267-9477    

DOI:10.1039/a906100b

出版商:RSC    

年代:1999

数据来源: RSC

摘要:

ATOMIC SPECTROMETRY UPDATE Industrial analysis: metals, chemicals and advanced materials Ben Fairman,*a Michael W. Hinds,b Simon M. Nelms,c Denise M. Pennyd and Phill Goodalle aLaboratory of the Government Chemist, Queens Road, Teddington, Middlesex, UK TW11 0LY. E-mail: BEF@LGC.CO.UK bRoyal Canadian Mint, 320 Sussex Drive, Ottawa, Ontario, Canada K1A 0G8 cIRMM, Retieseweg, Geel, Belgium B-2440 dShell Research and Technology Centre, Thornton, P.O. Box 1, Chester, UK CH1 3SH eBNFL, SellaÆeld, Seascale, Cumbria, UK CA20 1PG Received 8th October 1999 1 Metals 1.1 Ferrous metals 1.2 Non-ferrous metals Table 1 Summary of analyses of metals 2 Chemicals 2.1 Petroleum and petroleum products 2.1.1 Petroleum products 2.1.2 Fuels 2.1.3 Oils 2.2 Organic chemicals and solvents 2.2.1 Organic chemicals 2.2.2 Solvents 2.3 Inorganic chemicals and acids 2.4 Nuclear materials Table 2 Summary of analyses of chemicals 3 Advanced materials 3.1 Polymeric materials and composites 3.2 Semiconductors and conducting materials 3.3 Glasses 3.4 Ceramics and refractories 3.5 Catalysts Table 3 Summary of analyses of advanced materials 4 References This Atomic Spectrometry Update is the latest in an annual series appearing under the title `Industrial Analysis'. This year there have been several changes to the structure of the review.Some rearrangement of the Petroleum and petroleum products section, and some refocusing of the Chemicals section, has taken place.Also the Semiconductor section has been given a wider remit and is now called Semiconductors and conduction materials. It is hoped that these changes will meet with the approval of regular readers of this review and the authors and review co-ordinator would appreciate any constructive comments that may come to mind. In the area of organic and non-metal analysis there has been an increase in the use of indirect techniques for quantiÆcation of the organic compound of interest, i.e., the analysis of either complexed or inherent element by atomic spectrometry methods to give an estimation of the amount of organic substance.Also microwave digestion methodologies have been used in some interesting applications. There has been a large increase in the number of publications and conference presentations in the area of high purity metal analysis, and not just for the precious metals. The papers covered in this review concentrate on both the analysis of purity (difÆcult with respect to standards) and trace impurities (difÆcult with respect to matrix effects and sensitivity).Not much real novel work was encountered in the Æelds of the advanced materials sections and the avid reader will notice that these sections may be slightly shorter than other years, especially the Ceramics and refractories section, although the systematic analysis of REEs by Chinese workers continues. In general, improvements in sample preparation and instrument sensitivity have contributed most to the work covered by this year's review, especially in the nuclear and semiconductor industries, where the advances in ICP-MS instrumentation are now yielding sub-femtogram detection limits without preconcentration steps.If only we all could work with dark current blanks. 1 Metals The analysis of ferrous metals, non-ferrous metals and their alloys by analytical atomic spectrometry is covered in this section. A summary of the analytical methods reported for metals in the time period under review is given in Table 1. 1.1 Ferrous metals Advances continue in solid sample analysis to obtain qualitative and quantitative information. The application of laser-induced breakdown spectrometry (LIBS) to depth proÆling Zn-coated steels was the subject of two reports. In one,1 a 308 nm collimated beam was used to obtain Øat ablated proÆles in Zncoated steel. The depth resolution was 8 nm per pulse range. The other2 investigated use of the second derivative of the zinc intensity proÆle and the use of a simple model of laser ablation with a Gaussian beam to improve the depth measurement.The iron to zinc intensity ratio was also used for calibration from known standards. Light emitted from a focused ion-beam gave information on the elemental composition and chemical state of iron± chromium alloys.3 The authors claim that chemical mapping and depth proÆling are also possible with this technique.Secondary ion mass spectrometry (SIMS)4 was used in combination with transmission electron microscopy to study the evolution of grain boundaries in a nickel±chromium±iron alloy. X-ray Øuorescence spectrometry (XRF) is a well established analytical tool but work has continued on obtaining more qualitative information. The speciation of chromium in galvanized steel was found possible by the use of soft X-ray Øuorescence spectrometry (XRF).5 This was accomplished by *Review co-ordinator, to whom correspondence should be addressed and from whom reprints may be obtained. J.Anal. At. Spectrom., 1999, 14, 1937±1969 1937 This Journal is # The Royal Society of Chemistry 1999Table 1 Summary of analyses of metals Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Ag High phosphorous brazing alloy AA;F;L Sample (0.1 g) was dissolved in 150 ml 1 : 1 HNO3, 5 ml 20% tartaric acid and 5 ml 20% citric acid, then diluted to 250 ml.A 10 ml aliquot was diluted to 100 ml with mixture of 0.25% citric acid, 0.25% tartaric acid and 1% HNO3 208 Al Nickel-based alloys AA;ETA;L Sample dissolved (0.01 g) in HCl±HNO3 (4 : 1) via closed vessel microwave oven dissolution procedure. Detection limit: 9.6 and 22 pg for deuterium- ETA and Zeeman-ETA, respectively 209 Bi Steels AA;ETA;L Samples (0.25 g) dissolved in 4 ml HCl and 2 ml HNO3 in a PTFE Øask within microwave oven. Bi was separated from iron by complexation with the ammonium salt of dithiophosphoric acid O,O-diethyl ester and adsorption onto activated carbon.Analyte was desorbed by a small volume of nitric acid 210 Cr Coated steels AA;F;L The surface coating of circular (64.5 mm diameter) steel sample was dissolved in 30 ml 1 : 1 HCl and the sample washed with water. The solution and washings were combined, mixed with 5 ml of 200 mg ml21 calcium nitrate and diluted to 100 ml 211 Co Steel AA;FI-F;L Dissolved sample was passed through a minicolumn packed with poly- (aminophosphonic acid) chelating resin.Co was eluted with 0.2 M HNO3 to FAAS via a Øow injection manifold. Detection limits: 0.15 mg l21 212 Hg Gold bullion AA;ETA;L Samples (200 mg) were dissolved in 9 : 1 HCl±HNO3 and brought to volume (25 ml) with 60±80% HCl. Some silver chloride (major silver component of gold bullion) may precipitate but does not co-precipitate Hg. Detection limit: 20 mg g21 213 Mo Steels AA;F;L Triethanolamine was added to dissolved sample to reduce interferences in an air±acetylene Øame 214 Mo Steels XRF;–;S None 215 Mo Steels AA;ETA;L Samples (0.25 g) dissolved in 4 ml HCl and 2 ml HNO3 in a PTFE Øask within microwave oven.Mo was separated from iron by complexation with the ammonium salt of dithiophosphoric acid O,O-diethyl ester and adsorption onto activated carbon. Analyte was desorbed by a small volume of nitric acid 210 Ni Brass AA; FI-ETA;L Sample was dissolved by an on-line electrolytic process and presented to the ETA by an automated Øow-injection system.Detection limit: 0.003% (m/m) 25 P Iron MS; ETVICP; L Sample (0.1 g) dissolved in 4 ml aqua regia (3 part HClz1 part HNO3), then brought to volume in 10 ml with HCl. Iron matrix removed by 4- methylpentan-2-one solvent extraction. Zr added as a chemical modiÆer in the ETV. Detection limit: 0.008 mg g21 12 S Iron and steel MS; ICP; G Dissolved sample distilled at 250 �C under Ar which evolves H2S gas.The gas is collected and stored in sealed plastic bags 13 Si Tungsten AE;ICP;L Samples (0.5 g) were dissolved in 4 ml of H2O and 1 ml of HNO3 with slow dropwise addition of HF. Water was added with 1 g citric acid and the solution was neutralized to pH 7 with ammonia. The solution was brought to 100 ml and psented to the ICP. No high Si blanks observed when quartz nebulizer and glass spray chamber used 216 Sn Brass AA; FI-ETA;L Sample was dissolved by an on-line electrolytic process and presented to the ETA by an automated Øow-injection system.Detection limit: 0.001% (m/m) 25 Ta Iron and low alloy steel AE;ICP;L Tantalum was co-precipitated from iron in dissolved samples by the addition of 6% cupferron. 40 ml of 50% HCl added to minimize iron precipitation. Detection limit: 0.06 mg g21 217 Ti Steels XRF;–;S None 215 U Aluminium MS; ICP; L Samples (1 g) dissolved in 20 ml 9 M HCl for 3 h in a sealed PTFE vessel at 200 �C. Uranium was separated from the matrix by passing solution through a column Ælled with 75±150 mm MCI GEL CA08P and eluting with HCl.Sulfuric acid was added to the eluate. The resulting residue dissolved in 5 ml 1 M HNO3 then presented to ICP-MS. Detection limit: 0.02 ng l21 218 Zn Copper-base alloys AE;ICP;L The dissolved sample was reacted with 1-(2-thiazolylazo)-2-naphthol (TAN). Zn and the copper matrix reacted with TAN and only the Zn complex was retained on a Sep Pak C18 cartridge and eluted with ethanol.The ethanol was evaporated and the complex decomposed with nitric acid. Preparation serves to separate the Zn from the matrix and to pre-concentrate Zn 219 Various Aluminium, zinc, and steel AA;F/ETA;L Analytes were preconcentrated as iodo complexes on Amberlite XAD-1180 resin. Detection limit ranges: FAAS 0.08±4.4 mg g21 and ETAAS 0.012± 0.016 mg g21 220 Various Antimony AA,MS; ETA,ICP;L Three matrix separation techniques were studied. Detection limit comparison is given for both methods of detection 28 Various (5) Bronze XRF;L Sample dissolved in HCl±H2O2 and made to volume. An aliquot was spotted onto Ælter paper, air dried, then vacuum dried for 30 min and presented to XRF (Rh tube).Detection limits: for Cu, Pb, Sn, Fe and Zn were 3, 9, 6, 14 and 3 mg ml21, respectively 221 1938 J. Anal. At. Spectrom., 1999, 14, 1937±1969comparing peak positions and shapes of the Cr L spectrum of the sample with spectra obtained from pure chromium compounds such as: CrN, Cr23C6, Cr2 O3, CrPO4, and Cr(OH)3.It was reported that this method could differentiate between Cr III and Cr IV. Carbon proÆling in gear teeth (after failure) was accomplished by wavelength dispersive XRF interfaced to a scanning electron microscope (SEM).6 The calibration curve was linear for carbon in gear steel standards and carbon was determined at depth intervals on a crosssectional plane of the specimen. An automated system for the Table 1 Summary of analyses of metals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref.Various (4) Cobalt-based alloys AA;HGETA; L Aliquots of the dissolved sample were mixed with KHB4 and NaOH to generate the hydride of the element. The graphite furnace was pre-treated with Pd to trap the hydride 222 Various Copper and steel MS;LAICP; S None 14 Various Copper TXRF;L Copper matrix removed from dissolved sample by electrolysis (0.2 A, 8 h).An aliquot (10 ml) of remaining sample solution placed and dried on Si wafer under vacuum. This was repeated 5 times before analysis. Detection limits range 0.77 ng g21 (Zn) to 0.78 ng g21 (Ca) 223 Various (10) Gallium MS;ICP;L Most elements (Ag, Bi, Co, Cu, Fe, Ni and Pb) were determined after direct dissolution of the gallium. Other elements, Al, Cd and Mn, were determined after removal from the matrix with HCl±MIBK solvent extraction. Results obtained were validated by GFAAS 224 Various (4) Germanium AA;ETA;S Samples (100 mg) were washed with HF±HNO3±H2O (2 : 1 : 3) prior to placement in a graphite atomizer. Detection limits: 100, 0.1, 0.2 and 1 ng g21 for Hg, Na, K and Li, respectively 225 Various (3) High-carbon ferrochrome AE;ICP;L Sample (0.25±0.5 g) was fused with 2.5 g Na2O2 at 650 �C, extracted with 80 ml boiling water then acidiÆed with 20 ml HNO3.Solution was brought to volume with water and analysed 226 Various Iron and steels AE,MS; ICP;L Dissolved sample mixed with oxyethylidenediphosphonic acid, Mn or Cr and was passed through a column of tetraphenylmethylenediphosphine oxide stationary phase on styrene-divinylbenzene macroporous copolymer support.Analytes were retained on the column, eluted then passed on to the ICP 227 Various (10) Mercury AA;ETA;L Sample dissolved in HNO3 and either analysed directly or matrix reduced with reductant: hydrazine HCl, ascorbic acid or oxalic acid. Direct analysis of dissolved solution yielded detection limits: 0.03 mg g21 for Al, Cd, Mn; 0.05 mg g21 for Cu, Co, Cr, Fe, Ni, Pb; 0.02 mg g21 for V 228 Various (5) Nickel AF;HG;L Dissolved sample was treated with lanthanum hydroxide to precipitate the analyte elements.Analytes were re-dissolved in 40% HCl and diluted (Se, Te, and Bi). For As and Sb the solution was diluted with the addition of thiourea and citric acid. Aliquots mixed with sodium borohydride to generate hydrides.Detection limit: 0.1, 0.15, 0.11, 0.1 and 0.45 mg g21 for As, Sb, Se, Te and Bi, respectively 229 Various (4) Scandium AA;F,ETA; L A 50 mg sample was dissolve in 1 ml 50% HCl and made up to 10 ml with water 230 Various (7) Silver MS; LA-ICP;S None 16 Various (6) Silver NAA;L Silver was dissolved in HNO3 then HCl was added to precipitate the silver. Another separation was applied in which analytes were co-precipitated by the addition of the Pb salt of pyrrolidine dithiocarbamate.Both separation methods produce good results 26 Various Steel AA;F;L Carbide forming elements are isolated by dissolving the non-carbide forming elements with H3PO4 (2 : 1). The carbides were centrifuged, washed and dried then dissolved in HCl±HNO3±HF (10 : 5 : 3) in a TeØon beaker 9 Various REEs (14) Steels MS;FI-ICP;L The addition of boric acid during dissolution process with HF prevented the precipitation of insoluble Øuorides of REEs. QuantiÆcation limit ranged from 0.008 to 0.040 mg g21 for Lu and Nd, respectively 231 Various Steels AE;spark;S A small piece of steel was embedded in an ingot of tin by placing the piece in a mould and pouring molten tin into the mould.Bottom surface of the ingot was ground and presented for analysis. Applicable to steel sample of any shape or thickness having a diameter of ¢6 mm 232 Various REEs (3) Steels AE;FI-ICP;L Water, HNO3, HCl and HF were added to the sample in a closed vessel microwave oven and heated.Upon cooling a solution of H3BO3 was added to bind Øuoride and to facilitate the dissolution of precipitated microcrystals and then the solution re-heated. Detection limit: 0.008± 0.04 mg g21 233 Various (16) Tantalum MS;FI-ICP;L Sample dissolved in HNO3±HF, diluted, then passed through a Øow injection column packed with Dowex 50WX8. Analytes eluted with 5 M HNO3±0.5 M HF into the instrument. Detection limit: 0.3±6 ng g21, depending on the element 234 Various (8) Titanium AA;ETA;S Small pieces were cut from titanium bars (0.2±5 g), etched wth 5% HNO3± 2% HF, washed and dried 23 Various (12) Tungsten AA;ETA;S Small samples (0.15±100 mg) taken for analysis.Detection limits range from 0.01 to 4 ng g21 for elements determined 24 *HG indicates hydride generation and S, L, G and Sl signify solid, liquid, gaseous or slurry sample introduction, respectively. Other abbreviations are listed elsewhere. J. Anal. At. Spectrom., 1999, 14, 1937±1969 1939classiÆcation of steel was accomplished by comparing the elemental composition of 12 elements in a sample (by energy dispersive XRF) to the composition of 19 steel standards via an artiÆcial neural network.7 Metal alloys were sampled by rubbing with diamond impregnated polymer discs. The discs were analysed by laser ablation inductively coupled plasma mass spectrometry (LAICP- MS).8 It appears that 13C can be used as an internal standard and calibration with only one certiÆed reference material (iron based) was required for main component determination.Methods involving dissolved metal samples continue to brelevant part of metal analysis. The majority of papers involving AAS, ICP-AES and ICP-MS focus mainly on the sample preparation (see Table 1); however, some papers are worth mentioning. The carbide components of a high speed steel were isolated by dissolving only the non-carbide components in phosphoric acid. Then, the carbide forming elements Cr, Mo, Ti, Nb, Zr, W, V and Fe were separately dissolved for determination by Øame atomic absorption spectrometry (FAAS).9 Species of vanadium (V or VI) in steel were separated by a relatively simple chromatographic separation10 following sample dissolution. Vanadium was determined by FAAS.The determination of phosphorous and silicon in iron and steel was carried out by converting these to molybdate complexes with separation through a dextran gel column.11 Both elements were retained on the column as molybdate species and were eluted through different processes. Molybdenum was determined by ICP-MS and the concentration of P and Si were calculated based on the stoichiometry of each Mo complex.In another paper, electrothermal vaporization (ETV) ICP-MS was used to determine P in high purity iron.12 The iron matrix was separated by solvent extraction and zirconium was used as a chemical modiÆer to avoid interference from residual iron after solvent extraction.The limit of detection was 0.008 mg g21 in iron. In another study, sulfur in iron was converted to H2S gas, collected in sampling bags and then determined by isotope dilution ICP-MS.13 For samples containing 2 mg g21 sulfur the RSD was 2.6%. 1.2 Non-ferrous metals For non-ferrous metals, solid sampling spectrometric method development continues to be strong. Copper standards were analysed for 15 elements by LA-ICPMS with an internal standard set at the Øank of the 63Cu peak at mass 62.5.14 Detection limits ranged from 0.002 mg g21 for Bi to 0.33 mg g21 for Mn.The authors extended this work to solutions where they found that the ion signal measured on the peak tail is directly proportional to the element in the plasma, stable and independent of peak shape. From this solution standards were used to calibrate LA-ICP-MS measurements on the same metal matrix15 and ratioed to the same `off peak' internal standard (matrix element).Good recoveries were reported for high purity reference standards. A specially designed laser ablation cell was made which permitted LA-ICP-MS analysis of antique silver objects that would not Æt into a normal cell.16 The cell Ætted onto the object at a convenient location where laser sampling can occur without being easily noticed. An adjustable sample positioning device was made to hold the object for laser sampling. The small craters (100 mm diameter) are not easily observed in antique pieces which leads to `virtually non-destructive' sampling.The crater to crater repeatability was less than 10% RSD (n~3) for most elements. Limits of detection were below 2 mg g21. A portable energy dispersive XRF spectrometer was used to analyse ancient metal artefacts on site rather than in the laboratory.17 Qualitative or semi-quantitative information was acceptable for the diagnostic purposes noted in this report. However, the chief advantages were the non-destructive analysis and portability of the instrument.A wavelength dispersive XRF attached to a scanning electron microscope (SEM) and LA-ICP-MS were used in the characterization of elemental components of discoloured areas of thin (50 mm) aluminium foil.18 Eleven elements were studied and elevated concentrations of most the elements were found in the discoloured areas in comparison to the normal foil. The effect of cooling rate on the sequence of intermetallic phase precipitation in aluminum alloys was studied by energy dispersive XRF attached to SEM.19 Samples were taken at a speciÆc melt temperature, then `frozen' by rapid cooling and presented for analysis after etching or polishing (depending upon the analysis required). In another paper, the carbon K Xray spectra of mechanical alloys of niobium or tungsten and carbon were studied as a function of time by an electron probe microanalyser20 from which the composition and the size of particles were elucidated.Radiofrequency glow discharge AES21 was applied to the determination of gold in precious metal alloys. Results were quite close to Ære assay values; however, the precision must be improved at least ten-fold to one part per thousand or better. In another study, the depth distribution and bonding states of phosphorus implanted in titanium was affected by AES, SIMS and PIXE.22 Pieces of the refractory metals titanium23 and tungsten24 were analysed directly by GFAAS with aqueous calibration standards.In the case of titanium, matrix residue was removed by adding 50% HNO3zHF and covering it with 2±3 mg of carbon powder. For tungsten, H2 gas was used during the pyrolysis step to eliminate the high background from the evolution of WO3. Most of the AAS, ICP-AES and ICP-MS abstracts reviewed were application or sample preparation orientated and are summarized in Table 1. However, a few papers should be highlighted. An automated on-line dissolution system was tested for the determination of Sn and Ni in brass by ETAAS.25 The metal sample was dissolved by anodic electrodissolution in a Øow injection system and collected in an autosampler cup for presentation to the ETAAS.The precision was 4 and 5% RSD for Sn and Ni, respectively, for different samples (n~5) at concentration levels 0.064±0.079% (m/m). The results obtained were similar to that from ICP-AES (non-automated sample preparation) and the automated sample throughput was 30 samples per hour.Trace impurities in silver (Au, Co, Cu, Fe, Hg and Zn) were separated from the matrix through a two step precipitation followed by neutron activation analysis.26 Determined values were similar to the reference values for the silver samples; however, sensitivity would be improved with an increase in neutron Øux from the radiation source. Bullet samples were dissolved and analysed by ICP-MS and used for comparison in a criminal investigation.27 Trace element composition of the bullet fragments and the Pb isotope ratios were determined.One study compared three matrix separation procedures for the determination of trace elements in antimony with detection by both ETAAS and ICP-MS.28 All three separation techniques removed w99.99% of the antimony. A comparison of the detection limits for ETAAS and ICP-MS was given. 2 Chemicals 2.1 Petroleum and petroleum products As described in the summary of this review, this section has been split in a slightly different way from previous reviews: 2.1.1 Petroleum products, including gasoline, etc., naphtha condensates; 2.1.2 Fuels–coal, heavy fuel oil, diesel fuel; 2.1.3 1940 J.Anal. At. Spectrom., 1999, 14, 1937±1969Table 2 Summary of analyses of chemicals Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. PETROLEUM AND PETROLEUM PRODUCTS– As Natural gasoline and gas condensates AA;ETA;L An in situ absorption technique, using Pd alloy as the solid absorbent, has been developed to directly determine arsenic in the sample, including the volatile organic arsenic 33 C Organic contaminants in soil AE;SFE-ICP;L SFE connected on-line to AE instrumentation was used to determine non-metals in soil samples 235 Hg Natural gas condensate and hydrocarbons AFS;F;L A new technique for the direct determination of total mercury is reported.The samples are vaporized and the mercury species absorbed onto a gold trap (Amasil) which, when heated to 900 �C, released the mercury vapour in to the AFS system 236 Hg Natural gas condensate MS;ICP;G Operating conditions for the GC are given; 7 species of mercury were well separated 237 Hg Petroleum MS;GC-ICP;L The use of GC-ICP-MS has been studied and reported.Various columns and coupling devices were included in the study, the Ænal system separating and quantifying seven mercury species in 6 min 31 Ni Petroleum products XRF;–;L A recently developed EDXRF instrument was successfully applieto the simultaneous determination of Ni, V and S as a substitute to conventional ICP and XRF 238 P Organic contaminants in soil AE;SFE-ICP;L As for C 235 Pb Gasoline, pottery, whole blood MS;ICP;L Lead isotope ratios were determined by ICP-MS in the study of the source of lead in the residents of a small town in Mexico 37 Pb Gasoline AA;F;L The lead alkyl present in gasoline was extracted into nitric acid using microwave digestion, which converted the lead into the inorganic form under high temperature and pressure.After separation the nitric acid fraction was analysed 35 Pb Gasoline AE;ICP;L Details method for the determination of Pb in gasoline 34 S Petroleum products XRF;–;L As for Ni 238 S Organic contaminants in soil AE;SFE-ICP;L As for C 235 Si Organic contaminants in soil AE;SFE-ICP;L As for C 235 V Petroleum products XRF;–;L As for Ni 238 Various Petrochemical products MS;ICP;L Uses and applications of ICP-MS in the petrochemical industry are discussed 239 Various Naphtha MS;ICP;L The naphtha was emulsiÆed with Triton X-100 before introduction into the plasma. This signiÆcantly lowered the background attributed ArC, and reduced the amount of oxygen required to burn off the carbon, which in turn improved the detection limits 29 OILS, FUELS AND CRUDE OIL FRACTIONS– Various Petrochemical products AE;ICP;L MS;ICP;L The difÆculties of analysing volatile petrochemicals and method of overcoming them are discussed 38 B Lubricating oil AE;ICP;L Butanol was used as the diluent and on a 10-fold dilution of the sample no matrix matching was required 240 Cd Crude oil AA;F;L Cd, Pb and Ni are determined in burnt and unburnt crudes, to provide useful insight into the fate of the elements when using burning as remediation 241 Cl Fuel oil EDXRF;–;L Discusses the use of EDXRF analysis with monochromatic excitations to enable trace analysis in fuel oil 242 Hg Hydrocarbons, natural gas condensates AFS;F;L Vapour generated from the samples are trapped on an Au sand trap; the absorbed Hg was released by heating for determination by AFS.Seven species of Hg were studied 236 Hg Natural gas condensates MS;ICP;G The paper discusses the separation of 6 organomercury species and the relative detection limits achieved. Conditions and programmes are detailed 32 I Fuel oil EDXRF;–;L As for Cl 242 Ni Crude oil AA;F;L As for Cd 241 P Lubricating oil AE;ICP;L As for B 240 P Fuel oil EDXRF;–;L As for Cl 242 Pb Crude oil AA;F;L As for Cd 241 Si Crude oil AE;ICP;L This work describes the use of a direct injection nebulizer to overcome the species volatilization effects of the Si compounds 55 S Fuel oil EDXRF;–;L As for Cl 242 S Fuels, diesel fuels XRF;–;L The paper contrasts various methods for the determination of sulfur 50 Various Waste oils AE;ICP;L Low level determination of non-metals using the prominent lines in the 130±190 nm range is discussed 64 Various Aviation engine oil AE;ICP;L To improve the detection limits on low wear engines' used oil samples, activated charcoal and dry digestion procedures have been used as a pre-concentration step. 12±20 fold improvement is reported 56 J. Anal. At. Spectrom., 1999, 14, 1937±1969 1941Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. COAL– B Coal MS;ICP;L AE;ICP;L The samples were analysed by ICP-MS after acid dissolution. 200 coals were analysed with a precison of y8%. The results are compared with ICP-AE results 243 Hg Coal AA;FI-CV;L MS;ICP;L The samples were prepared using microwave digestion. The detection limit was 85 pg ml21 Hg for AA and 6 pg ml21 for ICPMS. All conditions given 44 Hg Coal AA;F;G The 4th stage of the thermal treatment in O2 programme using the Leco AMA 254 (thermal desorption stage) quantitatively traps the Hg present in the samples prior to determination by AA.The method requires no sample preparation 45 Hg Coal AA;CV;L The paper describes the use of pressurized digestion and a two stage amalgamation to determine trace levels of Hg. Detection limit was 2.5 ng, RSD was 7.3% and the average recovery was 99.8% 43 S Coal AA;F;L The sulfur was determined indirectly via a sample preparation route that Ænished with the formation of CrO4 2±, which was analysed by AA; this was proportional to the sulfur concentration 244 S Coal and coal products Standard and nonstandard methods Ten standard `wet' methods were used to analyse for sulfatic, pyritic and total sulfur.All were acceptable and recommendations in respect of ease of use were made 46 Various Coal, Øy-ash and leachates AA;F;L AE; ICP;L AA;ET;L The paper details the results of the ENEL±EDF round-robin in which 8 Italian and 4 French laboratories participated 48 Various Carbon materials XRF;–;S Standard addition, in the form of spiked pellets, enabled the analysis of, e.g., coal by EDXRF.It was successful for many reference materials 41 Various Bituminous coals AE;ICP;L AA;ET;L This paper discusses the evaluation of a high pressure, high temperature focused microwave system and compares the results to a conventional system via elemental results attained by ICPAE and ET-AA 47 Various Coal AE;GD;S The coals were pressed without binder to form pellets, then analysed by rf GD-AE.The technique was shown to be effective and sensitive in the direct analysis of solid samples 39 Various Coal XRF;–;S The paper reports the use of an on-line XRF monitoring system, which uses a probe Ætted with an X-ray transmitter 42 Various Coal AA;ETA;L The report studies the use of slurry introduction for coal analysis 40 Various Coal and coal ash MS;ICP;L The paper describes the evaluation of two digestion methods, open vessel and sealed microwave digestion.Much detailed metal extraction information is given 49 SOLVENTS– As Organic solvents, wine MS;ICP;L The use of a micro-scale Øow injection system employing a microconcentric nebulizer for efÆcient sample introduction is reported. The signal enhancement usually observed was signiÆcantly reduced, thus improving detection limits 245 As Environmental samples AA;HG;L The As was determined in the samples after a two-step solvent extraction pre-concentration procedure and back-extraction.Zinc hexamethylenedithiocarbamate in 2,6-dimethylheptan-4- one was used for extraction 246 As Ground and tap water AA;F;L The use of zinc hexamethylenedithiocarbamate as a chelating agent for extraction purposes is described 247 B High purity alcohol MS;ICP;L The alcohol samples were digested with HF and KF by placing on a bath until complete evaporation had occurred. After further treatment the resulting residues were dissolved in HCl prior to analysis 248 Hg Natural gas condensate MS;ICP;G Operating conditions for the GC are given; 7 species of mercury were well separated 237 Hg (species) Organic solution MS;ICP;L The stability over time of elemental mercury, methylmercury and inorganic mercury species was evaluated in heptane, toluene and mixed hydrocarbons 89 Pb Water AA;F;L Dual stage pre-concentration system, which uses FI on-line ion exchange and solvent extraction, using 1 M tetrabutylammonium bromide to complex the Pb, is discussed 88 Various Samples dissolved in organic solvents AE;ICP;L Reports the optimization of the ICP-AE spectrometer with a charged coupled device detector for the analysis of samples dissolved in organic solvents 249 Various Water AE;ICP;L The paper reports the addition of organic solvents to improve the detection limits in aqueous media.The addition of 3% butanol produced a 40°25% gain in signal to background; this was attributed to the change in droplet size 84 Various Organic solvents AE;ICP;L The study evaluates the effect of various solvents on the determination of the Ærst row transition metals 250 1942 J.Anal. At. Spectrom., 1999, 14, 1937±1969Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Various Organic solvents AE;ICP;L A novel chemometric technique has been applied to overcome differences in the solvent vapour loading and chemical composition between sample and standards.The result is a universal calibration for all solvents 91 Various Alcohols MS;ICP;L A FIA system for introducing low volumes (100 ml) of alcoholic analytical solutions is described 251 Various Methanol, NMP and decahydronaphthalene MS;ICP;L Cool plasma technique for ICP-MS has enabled the determination of wear metals such as Fe, Ca and K. The reasons for this are discussed 96 Various Organic solvents MS;ICP;L The advantages of using a microconcentric nebulizer with organic solvents are detailed 252 Various High purity solvents MS;ICP;L The drive for ultra-low detection limits by the semiconductor industry, as low as 1±10 pg ml21, required new sample preparation techniques.The use of an organic solvent evaporation system is reported 253 ORGANIC CHEMICALS– As Food coal-tar dyes AE;HG-ICP;L After sample pretreatment and analysis, the paper reports detection limits of 5 ng ml21 and the results on 67 food coal-tar dyes by AE 254 As Chinese medicine MS;ICP;L The samples were prepared via microwave digestion, followed by FIA-ICP-MS. Reference samples showed a recovery of 89±92% 71 Br (organo) Water AE;MIP;L A method for the determination of adsorbable organic halogens in water is described.Detection limits of 3 and 8 ng ml21 for chloride and bromide, respectively, were reported 255 C Solvents, base oils XRF;–;L The use of principal component analysis in EDXRS to determine the atomic components of organic matrices from the backscattering spectral region is demonstrated.Novel use of backscattering information 68 C Water IDMS;ICP;L A 13C enriched spiked solution of benzoic acid was used for the isotope dilution step. Equal ionization efÆciencies are obtained for carbon independent of type and mol. wt. of the dissolved organic compound. There was good agreement between the results obtained and conventional DOC method. The advantage of the method is that concentrations of heavy metals can be determined simultaneously 256 13C and12C ratio Amino acid, protein Twin quadrupole MS;ICP;L The ICP is used as an ionization source and the instruments are set up to monitor one isotope each.The correlation plot of measured 13C:12C ratio versus the actual 13C:12C ratio was linear with R~0.9998 257 Ca Phytic acid AA;F;L The use of EDTA enabled the direct determination of Ca in phytic acid; the results compared well with those after acid oxidation 258 Cl (organo) Water AE;GD;G Total chloride and organochloride was determined via the generation of chlorine.Experimental details are given 259 Cl Various organic and inorganic samples AE;ICP;L The paper discusses the use of `UVPLUS' to overcome the problems of making measurements at below 120 nm. Applications are also reported 260 Cl (organo) Water AE;MIP;L As for Br 255 Cl Halogenated hydrocarbon vapours AE;GD;G Experimental set-up and details are given. Measurements made in aliphatic and aromatic compounds permitted the ratio of C: Cl to be determined.The device has other potential uses 261 CN Industrial electrolytic baths, pharmaceutical formulations AA;F;L The CN is determined indirectly by passing the sample through a solid phase reactor containing AgI. The liberated Ag ions complexed by the CN are monitored by AA. The results obtained were very encouraging 262 Cinnarizine (as Co) Pharmaceutical preparations AA;F;L The cinnarizine was complexed with cobalt tetrathiocyanate and determined either spectrophotometrically at 622 nm or indirectly by the determination of Co by AA 263 Co Pharmaceutical preparations MS;ICP;L The paper reports the determination of cobaltamins and cobaltamides via HPLC using Ærstly UV absorption at 278 nm and secondly electrospray-MS for unambiguous identiÆcation of the eluted compounds and ICP-MS for the determination of Co 66 Cu Carboxymethychitin AA;F;L The sample was carbonized, then ashed with Mg(NO)3 and HNO3 at 650 �C for 3 h.The residue was boiled with 1 M HCl to near dryness. The resulting mixture was treated with ammonia to pH 4.5 and buffered at pH 4.5. The solutions were then analysed by AA 264 Cu Liquorice XRF;–;L Direct determination of metals in liquorice after ashing was attained by comparison with artiÆcial standard samples. The results compared well with ICP-AE results 70 Eu Aqueous solutions AE;ICP;L The use of polyoxalate systems for the extraction of lanthanide metals from their aqueous solutions in the presence of picrate anions is discussed 265 J.Anal. At. Spectrom., 1999, 14, 1937±1969 1943Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Fe Xylem sap of cucumber TRXRF; –;L AA;F;L The study of cucumbers grown in `lead free' and `lead contaminated' nutrient solutions containing either Fe citrate or Fe- EDTA was investigated with the use of TRXRF (Fe and Pb) and AA (Pb) 266 Fe Nepheline AA;F;L Sample preparation and precision data are detailed 267 Fe Licorice XRF;–;L As for Cu 70 H Solvents, base oils XRF;–;L As for C 68 Hf Organic stream samples XRF;–;L The analytical crystal choice is the critical parameter when determining Hf in organic solutions.The paper discusses and resolves the issues during the development of appropriate methodology 268 Hg Organic solvent MS;ICP;L AA;CV;L The stability over time of elemental mercury, methylmercury and inorganic species was evaluated in various solvents.The paper concludes that there are many factors affecting the recovery and speciation of Hg 89 Hg Cosmetics AA;ETA;L The use of ammonium hexachloropalladate±ammonium hexachlororhodate ±citric acid as a modiÆer in the determination of inorganic mercury; alkylmercury or phenylmercury by graphite furnace is reported 74 I Diiodoplatinum anti-cancer complexes MS;ICP;L The problems of determining I, because of low ionization potential, is overcome by the use of 10 mM KOH and the `S'-option on the instrument. This enabled accurate determination of Pt : I ratio, recoveries being 100.3°2.4% 269 I Glacial acetic acid MS;ICP;L Both conventional sample introduction and Øow injection analysis were performed.The results for each method and wash out proÆles for iodine using different carrier phases are presented 270 K Nepheline AA;F;L As for Fe 267 Mn (as methylcyclopentadienylmanganese tricarbonyl, MMT) Aqueous solution AED;GC;G Solid phase microextraction (SPME) was successfully applied to the determination of the gasoline additive MMT in aqueous solution.LOD for MMT Mn was 0.3 pg l–1 for headspace SPME and 0.5 pg l21 with liquid±liquid extraction (LLE). SPME has substantial advantages over LLE because of its simplicity, excellent reproducibility and freedom from solvents 271 Na Nepheline AA;F;L As for Fe 267 O Solvents, base oils XRF;–;L As for C 68 Organochloride Organic solutions MS;ICP;L AE;ICP;L A novel technique to correct for the errors arising from differences in volatility between the sample and standards is reported 82 Organosilicon Organic solutions MS;ICP;L AE;ICP;L As for organochloride 82 Organophosphorus Production waters MS;ICP;L AE;ICP;L The optimization of the use of silicon immobilized C18 mini-columns for the determination of phosphorus is reported.Various nebulizer systems tried gave LODs ranging from 47 mg l21 to 0.5 mg l21 covering both techniques 272 Pb Herbal medicine AA;F;L The use of a slotted sputtered quartz tube to enhance absorbance and improve precision is reported.LOD of 8.4 ng ml21 was achieved 273 Pb Xylem sap of cucumber TRXRF; –;L AA;F;L As for Fe 266 Pb Formaldehyde AA;ETA;L A home-made graphite probe furnace system was used to determine Pb in formadehyde 274 Pb Shampoo AA;F;L The sample pretreatment prior to analysis is detailed 275 Pb Medicine AA;F;L A staged ashing with acid dissolution was the sample pretreatment prior to analysis 276 Pr Aqueous solutions AE;ICP;L As for Eu 265 Pt Diiodoplatinum anti-cancer complexes MS;ICP;L As for I 269 Pt Anti-cancer drugs MS;ICL The coupling of HPLC and ICP-MS was evaluated in the separation and identiÆcation of inactive platinum species in platinum anti-cancer drugs 277 Sr Liquorice XRF;–;L As for Cu 70 Tannic acid Tea AA;F;L The tannic acid was determined indirectly by the determination of Cu2z after a sample preparation route–details given 65 Various Herbal medicines AE;ICP;L 16 elements were determined after pretreatment with HNO3 and H2O.LODs of 0.1±5 ng ml21 and recoveries of 85±103% were obtained 278 Various Trimethylgallium AE;ICP;L Impurities in trimethylgallium (16 elements) with LODs of 0.2± 18 ng ml21 were determined 279 Various Terephthalic acid AE;ICP;L Sample preparation prior to analysis is described. LODs were 0.001±0.03 mg ml21 280 1944 J.Anal. At. Spectrom., 1999, 14, 1937±1969Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Various Fulvic acid complexes ESMS;ICP;L In the abstract negative-ion electrospray mass spectrometry (ESMS) was used to simultaneously examine cationic and anionic solution composition. Determination of metal cations was accomplished by complexation with EDTA, to form negatively charged metal±EDTA complexes 78 Various Ca supplemented milk MS;ICP;L A method for the analysis of exponential decay curves involving several kinetic components has been evaluated using simulated data 281 Various Fulvic acid complexes MS;ICP;L Decay curves were analysed using the distribution analysis method tested in Part I.Rates of dissociation were measured for the metal complexes with varying rates of metals and fulvic acid 282 Various Organic materials XRF;–;L A review (125 references) is presented for the analysis of petroleum and petroleum products, organometallic compounds and polymers.Comparison and contrast with other methods versus XRF is the main focus 283 Various Diuretic pharmaceutical herbs XRF;–;L The study of the determination of various metals was based upon the XRF emission±transmission method 284 Various Medicine, organic materials XRF;–;L The paper discusses how to overcome the dark matrix problems particularly for organic matrices. The use of radioisotope excitation gives advantages over X-ray tube excitation in this area 69 Various Heroin MS;ICP;L A total of 188 heroin samples were analysed for 73 elements.The minimum detectable concentration for most elements was y0.3 ppb 285 Various Traditional Chinese medicine MS;ICP;L Three digestion procedures were compared for the determination of Sr, Pb, Co, Ni, Cu and Mn. 1, Digested in sealed bombs with HNO3±H2O2. 2, Microwave digestion with HNO3±H2O2. 3, Leaching with water for 2 h at 90 �C in a water bath. Results are compared and contrasted 72 Various Traditional Chinese medicine MS;ICP;L A continuation of procedures used in ref. 72. The results will be used for future studies of speciation 73 Various Metal organic compounds AE;ICP;L Trimethylgallium, a key raw material of MOCVD (metal-organic chemistry vapour deposition) in the electrical industry, has been analysed for 32 trace impurities 286 Various Peach leaves, coal AE;ICP;L The effect of digestion temperature on matrix decomposition, using a high pressure asher, has been investigated.The sample decomposition products were monitored using HPLC as the temperature was varied. The sample solutions were then analysed by ICP-AE. It was concluded that the ICP determination of the metals analysed in the sample materials is not dependent on acid digestion temperature 76 Various Organic matrix AE;ICP;L Experimental design has been used to evaluate and optimize the performance of a commercial ultrasonic nebulizer membrane desolvator interface.Parameters optimized were: 1, gas spray chamber temperature; 2, cooler (Peltier effect) temperature; 3, membrane desolvator temperature; 4, nebulizer gas Øow rate; 5, counter current gas Øow in membrane desolvator 287 Various High purity graphite MS;LA-ICP;S For laser ablation the main drawback is availability of suitable standards. Synthetic laboratory standards were prepared by doping graphite powder, followed by homogenization and pressing into a pellet.Results from external calibration and by means of relative sensitivity coefÆcients are compared 288 Various Water AA;F;L The indirect determination of Y and lanthanides was performed via the measurement of magnesium after extraction of the ternary complexes with purpurin (1,2,4-trihydroxyanthraquinone) and magnesium into isobutyl ketone. Preparation details and detection limits are given 289 Various Ultra-pure ClF3 MS;ICP;L Over 44 metals were determined.Cool plasma conditions were used to attain results for elements such as Fe. Results are discussed together with a thermodynamic justiÆcation for the residue technique 290 Various Aliphatic, aromatic, amino acids AE;GD;L MS;GD;L The use of particle beam glow discharge MS and AE is discussed, with diagram 291 Zn Carboxymethylchitin AA;F;L As for Cu 264 Zn Licorice XRF;–;L As for Cu 70 Zn Sea-water MS;APCI;L The anti-fouling agent (Zn) was determined by copper chelate formation and high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. LOD of 20 ng l21 was achieved 292 INORGANIC CHEMICALS AND ACIDS– Al Aluminium tetrabromophthalate AE;ICP;L Samples were microwave digested using a HNO3±H2SO4 mixture 293 J.Anal. At. Spectrom., 1999, 14, 1937±1969 1945Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref.As Copper oxychloride AA;ETA;L Samples were dissolved in dilute HNO3, and measured directly. The Cu matrix acted as an effective matrix modiÆer for this analysis 294 As Ammonium chloride AA;F;L Samples were acidiÆed with HCl, then NaBH4 was added and the AsH3 formed was transported to a heated quartz tube by Ar gas. As was deposited on the hot tube, dissolved off with 30% HNO3, then diluted and measured 295 As Gold electroplating solutions AA;ETA;L Samples were mixed with a buffered EDTA solution, AuI complexing agent and APDC.AsIII was extracted as the AsO2 ±± APDC complex using MIBK 296 As, Bi and Sb Electrolytic copper samples AE;ICP;L Samples were decomposed with HNO3, evaporated with HCl, then reconstituted with a mixture of HCl, KI, thiourea and water. The analytes of interest were converted to hydrides in a Øow system coupled to the ICP-AE 297 As and S Phosphine AE;ICP;G Phosphine gas was introduced to a pre-initiated Ar plasma enclosed in a quartz chamber.Calibration was achieved by introducing AsH3 and H2S gas, mixed with Ar, into the enclosed plasma 298 Au, Ru and Pd Acidic solutions and metal smelter samples AE;ICP;L The selected analytes were separated from solution by collection on a spherical macroporous epoxy±imidazole complexing resin, before elution and off-line measurement 299 Ba, Mg and Zn Hydrochloric and perchloric acids AE;ICP;L Hydrochloric and perchloric acid solutions containing the target analytes were prepared and aspirated into the ICP using an ultrasonic nebulizer 300 Ca and Mg Sodium chloride brines AA;F;L Ca and Mg were complexed with xylenol orange, then mixed with tert-butylammonium acetate.The ion pair so formed was retained on a C18 column before elution with methanol. A hydraulic high pressure nebulizer was used 301 Cd Calcium drug samples AA;ETA;S The drug powders were slurried in aqueous solution and analysed directly, using a Mo tube atomizer and thiourea as a matrix modiÆer 302 Cd, Cr, Pb and Hg Paper boards for food packaging AA;F;L Samples were either soaked in de-ionized water (extraction testing) or in an ethanoic acid solution (migration testing), and the extract analysed 303 Ce K3Li2Nb5O15 crystals MS;ICP;L Samples were digested on a hotplate with a mixture of sulfuric acid and hydrogen peroxide, then diluted with water 304 Co Cobalamins and cobinamides MS;ICP;L The cobalamin and cobinamide species were separated by HPLC, before on-line detection ( measurement of Co) using ICPMS 66 Co Ammonium thiocyanate solution AA;F;L Samples acidiÆed with H2SO4 were shaken with MIBK for 2 h.The extent of Co extraction (as thiocyanate complexes) into the organic phase was deduced by measuring these metals in the aqueous phase 305 Cr Bismuth tellurite AA;ETA;L Samples were dissolved with concentrated HCl. Other acids and triammonium citrate were added to prevent hydrolysis of the parent material 306 Cr Tanned leather samples AA;F;L The samples were digested with aqua regia for total Cr determination 307 Cr and Fe ArtiÆcial diamonds XRF;–;S No sample pre-treatment performed 308 Cu Silver nitrate solution AA;F;L The analytes of interest were extracted by liquid membrane enrichment.The membrane (as an emulsion) was de-emulsiÆed into its organic and aqueous components, and the target analytes measured in the aqueous fraction 309 Fe Doxycycline hydrochloride AA;F;L Samples were dissolved in HCl on a hotplate, then diluted with 1% HCl 310 Fe Sodium chloride brines AE;ICP;L Fe was added to synthetic sodium chloride solutions, for studies of the behaviour of Fe ions and atoms in the ICP 311 Fe, Mo and Ni Fe±Mo±Ni alloys XRF;–;S No sample pre-treatment performed 312 I Table salt and kelp samples AA;F;L Samples were dissolved or digested, then mixed with a standard AgNO3 solution. The AgI formed was precipitated by centrifugation, and the I concentration calculated indirectly from the Ag concentration left in the supernatant 313 La Synthetic acidic solutions XRF;–;L La was extracted from the samples with tributyl phosphate, in an on-line system coupled to a Øow through cell aligned with the X-ray source 314 Li Lithium salts MS;–;L Samples were dissolved in dilute HCl, in preparation for Li isotopic composition analysis 315 Mn Zinc sulÆde±manganese electroluminescent Ælms AA;F;L The Ælm samples (on glass slides) were dried to constant weight.The Ælm was then dissolved with 1 : 1 HCl, and rinsed into a container with water, for analysis. The slide was re-weighed to calculate the weight of Ælm removed 316 Mn Dyestuffs XRF;–;S Samples of the dye were pressed into pellets 317 Na Sodium antimonate solutions AE;F;L Sodium antimonate was dissolved with a mixture of 20% tartaric acid solution and concentrated HCl. Potassium chloride was added as an ionization suppressant 318 1946 J.Anal. At. Spectrom., 1999, 14, 1937±1969Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Ni Alkali metal salt solutions AE;ICP;L Ni was complexed with 1-(2-thiazolylazo)-p-cresol, then extracted with an organic solvent. The Ni was then recovered by back extraction with dilute nitric acid or by evaporation of the solvent, followed by digestion of the residue 319 P Water samples AA;F;L Samples were mixed with Na2MoO4, FeCl3 (in HCl) and acetic acid, to form the 11-molybdoironphosphate complex.This was extracted with cyclohexanone and the extract analysed directly 320 Pb Coral AE;DCP;G Coral samples were dissolved in dilute HCl, diluted 5-fold with water, then injected into a dilute HCl stream and merged with a K(CN)6±NaBH4 mixture to generate PbH4 (transported to the plasma via a gas-liquid separator) 321 Pb Antacids and calcium compounds MS;ICP;L Samples digested with HNO3 or HNO3±HCl on a hotplate for 5± 10 min, then diluted with water 322 Pb Calcium supplements MS;ICP;L Ca supplement tablets were ground, dried and digested with HNO3 at high temperature and pressure, then diluted with water 323 Pb Nickel sulfate electrolyte AA;F;L Samples were mixed off-line with HCl, KI and H2O, then extracted on-line with MIBK.The extract was analysed directly 324 Pb Calcium supplements MS;ICP;L Samples were dissolved in concentrated HNO3, then diluted with water to a dissolved solids concentration of 0.2% (m/v) 325 Pb Cyclamate artiÆcial sweetener AA;F;L Sodium cyclamate was indirectly determined, using an on-line continuous precipitation system to oxidize, then precipitate, the cyclamate with lead (as Pb sulfate).Pb was then measured and related to the cyclamate concentration 326 Pb, Cd, Cu and Zn Sulfuric acid AA;F;L Samples were diluted with water, mixed with KI, then Pb, Cd and Cu were extracted with MIBK, while Zn remained in the aqueous phase.Both phases were subsequently measured 327 Sb Tin oxide powder MS;GD;S Samples of tin oxide powder were pressed into pellets 328 Si Silica microspheres AE;MIP;S Silica powder samples of uniform particle size were passed into the plasma. The Si emission intensity was correlated with the particle size 329 Sm Aqueous standard solutions MS;RI;L Sm standard solutions were used with no further treatment.Resonance ionization (RI) mass spectrometry was used in this work 330 Te Indium antimonide AA;ETA;Sl The samples were slurried in aqueous solution and analysed directly using a palladium nitrate matrix modiÆer 331 Th and U Phosphate fertilisers and coal ash XRF;–;S No sample pre-treatment performed 332 V Aqueous solutions AA;F;L Vanadium(IV) and vanadium(V) species were mixed with KHphthalate and chromatographically separated on a C18 column before on-line detection 10 V Aluminium powder AA;ETA;S The samples were analysed directly, using Mg(NO3)2 as a matrix modiÆer 333 Zr Molybdenum MS;ICP;L Zr was separated from Mo in aqueous solution by solvent extraction with bis(2-ethylhexyl)hydrogenphosphate in cyclohexane 334 Various Aluminium salt cake AE;ICP;L Leachable metals were extracted from the samples by ultrasonication with water.Total levels of the analytes of interest were determined after complete dissolution of the samples with mineral acid mixtures 335 Various Semiconductor grade phosphoric acid MS;ICP;L Samples were diluted with water prior to analysis.Various different parameters, including dilution factor, plasma power and nebulizer type, were investigated 336 Various Aqueous solutions AA;ETA;S The increasing concentrations of the target analytes in an aqueous solution surrounding a plastic bag containing these analytes were measured over time. The results were used to examine the permeation properties of the plastic 337 Various Ultra-pure sulfuric acid HR-MS;ICP;L Samples were concentrated 20-fold by evaporation, then reconstituted in dilute acid 338 Various (5) Saline solutions and mineral waters AA;ETA;L The analytes of interest were retained on a mini-column of sulfoxine cellulose, then eluted and measured off-line 339 Various (5) Fluoroborate compounds AA;F;L Samples dissolved in acid solution 340 Various (5) Ca3(VO4)2 crystals AE;ICP;L Samples were dissolved in 50% (v/v) HNO3 341 Various (5) Sodium chloride brines and potassium hydroxide AE;ICP;L A chelating polymer resin was added to the samples (adjusted to an optimized pH) to collect the analytes of interest.The resin was Æltered, rinsed and passed directly into the plasma. The whole process was automated 342 Various (7) Solar grade silicon MS;ICP;S Samples were ablated with a laser and the ablated material transported to the plasma in an argon stream 343 Various (7) 30% zinc sulfate solution AE;ICP;G Samples were diluted by a factor of 10, then the analytes of interest were converted to the corresponding hydrides and transported to the detector via a frit based gas±liquid separator 344 J.Anal. At. Spectrom., 1999, 14, 1937±1969 1947Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Various (8) Potassium chloride solutions AE;ICP;L The analytes of interest were separated from the sample matrix by retention on a column of EDTrA cellulose incorporated in an automated Øow system and eluted with a dilute HNO3±HCl mixture 345 Various (10) Saline solutions AE;ICP;Sl A mixture of the sample, a chelating agent, Triton X-100, and Amberlite XAD-2 resin was prepared.The complexed analytes were retained on the resin, which was Æltered, dispersed in Triton X-100 (1%), then analysed as a slurry 346 Various (13) Tungsten trioxide AE;ICP;L Samples were dissolved in aqueous ammonia, diluted with water, then the analytes of interest were coprecipitated with a solution of La in HCl 347 Various (15) Aqueous solutions AA;ETA;L Non-pyrolytic boron nitride and pyrolytic boron nitride tubes, inserted into a standard graphite furnace, were tested as sample platforms for ETAA 348 NUCLEAR MATERIALS– Cs HA wastes, spent fuel MS;ICP;L Total and isotopic composition of Cs determined by coupled HPLC-ICP-MS.Cs separated on-line using SCX column (CS5, Dionex) with a mobile phase of 1 M HNO3.LOD for total Cs~16 pg g21. IDA using natural Cs used for quantiÆcation 123, 124 Er High burn-up Mo± U fuel TIMS, HPLC; GD-MS;– Double spike (Er-167±U-233) calibrated and applied to determination of Er :U atom ratio. HPLC separation prior to mounting on Ælament. TIMS measurement used as standard against which a direct measurement of Er :U atom ratio by GD-MS assessed 349 I-129 Ambient air MS;ICP;– Ice from refrigeration units or liquid Ar evaporators was added to aqueous NaOH to stabilize the sample.Sample pH was adjusted to 3±4, stable isotope carrier added and precipitated as PdI2 by addition of PdCl2 solution. Solid was separated and pyrolysed in tube furnace; evolved vapours swept into ICP-MS directly. A mathematical correction was applied to subtract contribution of Xe-129 isobar. LOD~30 fg I-129 (0.2 mBq) 350, 351 Pu Sea-water MS;ICP;L Standard radiochemical separation of Pu applied. Pu co-precipitated on: 1, Nd Øuoride; 2, Fe hydroxide carrier.Pu-242 tracer used. Fe carrier digested, acidiÆed to 8 M HNO3, loaded onto SAX column (AG1-X4), washed with 8 M HNO3 and Pu stripped with NH4I±HCl. Eluate taken to dryness, reconstituted and Øow injected into Q-ICP-MS with USN±membrane desolvation 352 Pu Environmental MS;ICP;L Instrumental LOD for Pu-239, Pu-240 and Pu-241 were 5, 1 and 1 fg cm23, respectively (0.01, 0.08 and 0.0002 mBq cm23). Precision for isotope ratios close to counting statistics observed for environmental samples after optimization of instrument parameter using a 23 experimental design 353 Pu U Solutions MS;ICP;L On-line separation on cation exchange column (Dionex CS10) with mobile phase of 2,3-diaminopropionic acid (40 mmol dm23) in aqueous nitric acid (0.2 mol dm23).Pu oxidized with AgO to PuVI prior to separation. QuantiÆcation by isotope dilution with242Pu spike and LOD~10 fg (100 ml injection). Determination of pg of Pu in w106 excess of U demonstrated 125 Pu Soil MS;ICP;L ID-MS using Pu-242 spike.LOD~18 and 13 ppq for Pu-239 and Pu-240, respectively 354 226Ra Groundwaters, soils MS;ICP;L Soils digested in m-wave. Ra-226 extracted on SAX resin. Ba-133 tracer used. Minimum sample sizes for waters and soil were 4 dm3 and 1 g, respectively. LOD~82 ppq 355 Tc Sea-water MS;ICP;L Tc and Re tracer separated from sea-water on a Cl± form SAX resin (Amberlite IRA-400). Analytes eluted in 10 M HNO3, Rh added as internal standard, samples diluted and run on Q-ICPMS using an USN with membrane desolvation.LOD~30 pg cm23 (0.02 mBq cm23) 356 Tc Soil MS;ICP;L Soils ashed, extracted with HNO3, Tc separated on TEVA (Eichrom Ind. Inc.) and Tc determined by coupled HPLC-ICPMS. LOD~20 mBq kg21 126 Tc Seaweed MS;ICP;L Samples extracted with 2 M HNO3 and 2 M NaOH, adjusted to 0.1 M HNO3, separated on a novel extraction resin and analysed by ICP-MS. Good agreement with radiometric counting methods observed 357 Tc Bentonite clay MS;ICP;L Leached with 2 M H2SO4±0.01 M Na bromate at 60 �C for 10 h.Extracted into Alamine-336 in CHCl3, back extracted into 1 M HNO3. LOD 0.3 mBq cm23 (cf. 0.34 mBq cm23 radiochemical method). Five-fold improvement in LOD using desolvating nebulizer 128 1948 J. Anal. At. Spectrom., 1999, 14, 1937±1969Oils–crude oil, lubricating oil, silicone oil. As usual, a summary of the literature for the review period is given in Table 2. 2.1.1 Petroleum products. Trace elements in naphtha, as in other petroleum processes, can cause poisoning of the catalyst during cracking. For example, Ni is a catalyst poison, V can cause corrosion problems and the release of toxic elements such as As, Hg and Pb into the environment during reÆning is a matter of serious concern. Kumar and Gangaharan29 note problems reported with ng levels of Hg in natural gas destroying the aluminium heat exchangers in the Skida facility, Algeria, and similar problems in Groningen, The Netherlands, and Æelds in the North Sea.Also, the levels of source-inherited metals such as Ni and V provides information on aspects of crude oil; in the case of naphtha and condensates the levels are low and reliable values are difÆcult to obtain. ICP-MS is a powerful and sensitive technique, but is difÆcult to operate in organic matrices. Overloading of the plasma with organic vapours cause changes in the physical properties of the discharge.Often the result is poor precision, carbon deposits on the sample and skimmer cones and occasionally complete extinction of the plasma. Various tools can be used to reduce the plasma overloading which include cryogenic desolvation, membrane desolvation, aerosol drying and oxygen feeding. This lead to the development of a simple method by Kumar and Gangaharan for the determination of V, Co, Ni, As, Hg and Pb in naphtha by ICP-MS. The samples are emulsiÆed using Triton X-100 (2 ml of naphtha with 1 ml of 2.5% Triton X-100 aqueous solution, with constant stirring for 20 min) prior to analysis.Oxygen was used to remove the carbon build- Table 2 Summary of analyses of chemicals (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Th Sea-water EC, MS;ICP;– Matrix removal and pre-concentration accomplished electrochemically at an anodically conditioned glassy carbon electrode. 10 min deposition at 20.15 V, stripped at z1.15 V, LOD~0.12 pg cm23.QuantiÆed by standard addition and for NASS-4 recoveries~100±120% (indistinguishable statistically from certiÆed value) 350 TrU Glass waste forms MS, ICP, a-spec., b-spec.;–;– Multi-technique methodology, including ICP-MS applied to determination of TrU nuclides in glass waste forms (simulants and `real' samples) 358 U Sea-water MS, EC;ICP;– As for Th 350 U isotopes, 99Tc, 135Cs, 151Sm Radwaste – ICP-MS shown to be Æt for purpose for measurement of U isotopes for risk assessment of tank wastes and replacing current TIMS methodology.Non-routine screening for other nuclides described 359 U WIPP brines MS;ETV,ICP;Sl Automated matrix elimination/preconcentration used onto small polymeric chelating beads (v0.2 mm). Beads separated from matrix, suspended in small volume and introduced into ICPMS via ETV 360 U Sediments MS;ICP;L 3 stage sequential extraction procedure (ex BCR) used to speciate U in sediments. Isotopic and chemical concentration determined 361 Various Radwaste and environmental MS;ICP;L Direct injection, high efÆciency nebulizer (uptake v100 ml min21) applied to determination of 226Ra, 230Th, 237Np, 238U, 239Pu and 241Am. LOD~70±400 fg cm23 119 Various (5) Radwaste and environmental MS;FI,ICP;L Ultra-trace and isotope ratio measurements using FI in conjunction with variety of MCN 121 Various WIPP brines MS;ICP;L `Dilute and shoot'.LOD for 238U~0.037 pg cm23 362 Various Concrete ICP;MS;S Application of LA-ICP-MS described.LOD~10 ng g21 for typical long lived radionuclides, e.g., Tc-99, Th, Np-237 and U 363 Various (4) Clays a-Spec., MS;ICP;L Clay leached with 1 M HNO3±20 mM KBrO3 at 65 �C for 12 h. Leachate extracted into D2EHP in OK. Analytes backwashed selectively, 5 M HNO3 (Am, Cm), hydroxyammonium chloride in 1 M HNO3 (Np), 60 mM Ti III in 3 M HCl (Pu). With appropriate tracers, recoveries~82°3% (Np), 91°1% (Pu) and 97°2% (Am, Cm).Am and Cm determined by a-spectrometry, remainder by ICP-MS. LOD~0.3 pg (Np), 4.5 pg (Pu), 3 fg (Am) and 0.1 fg (Cm). Decontamination factors of 2800 (Np) and 200 (Pu) were obtained with respect to laexcesses of U 129 Various Glass waste form AE;ICP;L Peroxide fusion, extraction of bead with hot water and acidiÆcation for determination of Si and B. Acid decomposition with HF±HClO4, sample fumed, evaporated 3 times with HF± HNO3, residue digested with HCl and any insoluble material fused with Na peroxide for determination of Li, Na, Mg, Al, P, Cr, Fe, Ni, Sr, Zr, Mo, La, Ce, Nd and U 364 Various (4) U FI, MS;ICP;L On-line matrix elimination using FI with TRU-Spec minicolumn.LOD~0.6, 5, 1 and 3 mg cm23 for Al, Be, Li and Mg in presence of 5 mg cm23 U 127 Various U oxide AE;ICP;L U oxide (0.1 g) microwave digested with HNO3±HF. Evaporated to incipient dryness three times with HNO3, reconstituted and applied to TBP coated column for matrix removal.Analytes eluted in 25 cm3 of 0.5 M HNO3 and 1 cm3 fractions analysed by ICP-AE for 23 analytes. Analytical recoveries~94±106%. 365 *Hy indicates hydride and S, L, G and Sl signify solid, liquid, gaseous or slurry sample introduction, respectively. Other abbreviations are listed elsewhere. J. Anal. At. Spectrom., 1999, 14, 1937±1969 1949up. The background at 40Ar13Cz was only 15 000 counts as compared with a 1 : 1 naphtha±xylene sample at 780 000 counts. The limits of detection were 0.6 mg l21 for V, 0.05 mg l21 for Co, 0.7 mg l21 for Ni and 0.1 mg l21 for As. Using a semi-quantitative approach detection limits of Hg and Pb were 0.12 and 0.09 mg l21, respectively.Comparative data was in good agreement. Further work on the determination of contaminants has been carried out during the review period. The main focus has been on simplifying the labour intensive sample preparation routes. As mentioned above mercury present in raw condensates or crude oils corrodes aluminium constructions and poisons catalysts.The analysis of natural gas condensates for mercury can be very difÆcult because of the volatility and complex nature of the sample and the variation of the mercury species. This poses many problems for the petroleum industry, and it is therefore important that the mercury content can be determined accurately to aid its control. A. Shafawi et al.30 have developed a rapid procedure for the determination of total mercury in gas condensates.The procedure involves the vaporization and trapping of mercury species by an Amasil gold trap at an elevated temperature (200 �C). The trap is then heated to 900 �C to release metallic mercury, which is determined by atomic Øuorescence. The mercury recoveries from seven species, dimethylmercury (DMM), diethylmercury (DEM), diphenylmercury (DPM), methylmercury chloride (MMC), ethylmercury chloride (EMC), phenylmercury chloride (PMC) and mercury(II) chloride (MC), which were spiked individually into gas condensates, were found to be in the range 80±100%.Considering the complex nature of the sample matrix, these reported recoveries are excellent. For each given species, the linearity (with calibration range) was better than r2~0.99. An added bonus was that the traps did not suffer from memory effects, which is so often the case for mercury determinations. Overall, the procedure offers rapid and consistent results without having to use digestion procedures or chemical modiÆers and reagents, which may introduce contamination.The LOD for the procedure was calculated to be 180 pg of Hg in toluene and 270 pg in condensate. The analysis of mercury in gas condensates, naphtha and gasoline was taken one step further by Tao et al.,31,32 who have successfully performed mercury speciation by GC-ICPMS. The GC column (DB 1701) was pre-treated with HBr, to increase the volatility of CH3HgCl during separation by converting it to CH3HgBr on the column.A l ml portion of sample was injected in the fast pulsed splitless mode with an automatic liquid sampler, with the column being operated via a temperature programme. The sample travelled down a transfer line to the ICP-MS, which was held at 150 �C and was coupled to the ICP torch at the ball joint. Via this route DMM, EMM, DEM, MMC, DBM (dibutylmercury) and EMC were well separated in 6 min; however, Hg0 and HgCl2 were unresolved.The latter was improved when the 1 ml sample was injected into the pre-treated column and Hg 0 was separated from HgCl2, which could not be determined by this method. The run time was y7.5 min. Detection limits ranged from 19 pg of Hg (EMM) to 200 fg of Hg (DMM), while the RSDs were 1.6± 3.8% for pulsed spitless injection and 1.6±2.7% for on-column injection. Another undesirable contaminant, because of catalyst poisoning during process operations and because of environmental concerns, is arsenic.Many of the methods available for the determination of arsenic require sample pre-treatment and subsequent analysis of the aqueous materials. These have their problems, primarily because natural gasoline and gas condensates may contain organic arsenic compounds that have lower boiling-points than inorganic arsenic compounds. Zhuang et al.33 have developed an in-situ absorption technique to determine arsenic directly using GFAAS. The sample is injected directly into the graphite tube containing the solid absorbent, a Pd alloy; this absorbs total arsenic, including volatile organic arsenic.Results show good precision and accuracy, the main problems relating to the addition of the solid absorbent into the graphite tube, which can cause imprecision. There continues to be keen interest in the determination of lead in gasoline and although there are standard methods available for such determinations, work continues to develop alternative methodologies.A method using ICP-AES has been developed,34 the standard and sample preparation being based upon an existing AAS method. The ICP-MS system was optimized using a chemometrics approach. After choosing the experimental design, running the experiments, modelling the experimental system and Ænally estimating the optimized factors (operating conditions), it was found that only 3 factors, power, observation height and sample solution feed rate had a signiÆcant inØuence on the response of the experiment. The optimized operating conditions were: observation height 12 mm; nebulizer pressure, 15 psi; sample Øow rate, 1 ml min21; power, 1550 W; outer gas Øow rate, 14 l min21; and intermediate gas Øow rate, 1.0 l min21.Two methods were developed, optimized and validated: 1, unleaded gasoline 5±25 mg l21; and 2, leaded gasoline 66± 198 mg l21. Overall, the developed ICP-AES method was more precise than the AAS method. An off-line hyphenation of microwave extraction and AAS has been used successfully to determine Pb in gasoline.Basically, 10 ml of gasoline and 5 ml of HNO3 (50 : 50) were added together and irradiated via a 4-step digestion programme, the alkyl Pb being converted to inorganic Pb. The two phases were separated and the acid phase was analysed by GFAAS. The recoveries of lead added to gasoline were 94±116%, with an RSD better than 2%. The work was reported as very accurate, simple, quick and contamination free.35 Two papers36,37 report the determination of Pb in gasoline in Mexico City. The Ærst is a straightforward monitoring process of the store of gasoline around the city, with reported Pb levels between 0.004±0.010 g per gal.The second paper deals with Pb isotope ratios to source the lead found in whole blood in the population of Mexico City. Comparison was made of Pb 208 : Pb 204; Pb 207 : Pb 204 and Pb 208 : Pb 204 in ceramic cookware and leaded gasoline and then related to the whole blood specimens.The sample was analysed by ICP-MS-ETV. It concluded that the predominant source of Pb in this population was the ceramic-ware used for cooking. The use of USN with microporous membrane desolvator in ICP-MS and ICP-AES is reported to remove 99% of the organic vapour. This overcomes the differences between samples and standard volalility and matrices and hence gives rise to a universal calibration.38 2.1.2 Fuels. The crude oil analysis normally detailed under fuels will now be included in the oil section. The mosrs received in the review period for this sub-section were for the analysis of coal.The use of coal varies from country to country but many millions of tonnes are consumed each year. The trace elemental composition of coal can give valuable information about its origin as well as the environmental impact of its processing and use. Several papers have investigated alternative methods for the analysis of coal which exclude time consuming and difÆcult sample preparation procedures.Radiofrequency GD-AES39 has been shown to be an effective and sensitive means for the analysis of various non-conductive materials in the solid state. In the study, raw coal samples were pressed without binder to form pellets which were held onto the source by a brass sample holder; trace and quantitative data were obtained. Silva et al.40 report on the application of the slurry technique 1950 J.Anal. At. Spectrom., 1999, 14, 1937±1969for trace metals determination in coal by GF-AAS. The slurries were prepared by weighing the sample directly into the autosampler cups (5±15 mg) and a 1.5 ml aliquot of diluent, consisting of 5% v/v HNO3, 0.05% Triton X-100 and 10% ethanol, was added to the sample. The stability and homogenization were maintained by manually stirring the slurry before measurements. Ten microlitres of matrix modiÆer (0.05% v/v Pd and 0.03% v/v Mg) were added to 20 ml of sample via an auto-sampler.For Pb determination, the calibration was performed with aqueous standards containing 20 and 100 mg l21 of Pb. It was found that a particle size of v44 mm was necessary to achieve good accuracy. The procedure is being extended for other elements, e.g., Cu and Cd. Although this method gives a direct approach, there are still many manual steps, and the reviewer wonders how representative 5±15 mg of coal is to the bulk of the sample.XRF also has a place in the analysis of solids, although obtaining standards for solid samples is always a difÆculty. Work reported41 has overcome this problem by the use of standard addition measurements on spiked pellets, using EDXRF. The procedure was successfully applied to a series of reference coals, e.g., NBS 1632a, NBS 1635 and BCR 180- 181. An on-line XRF monitoring system has been constructed to determine elements in pulverised coal.42 It uses a probe having an X-ray transmitter and an X-ray detector placed adjacent to a recessed chamber in a coal feed line with an X-ray transparent window.Pulverized coal travelling along the feed line collects in the chamber where the X-ray analysis takes place, a pressurized air tube blows out the accumulated coal back into the feed line and the next sample settles into the chamber. Hence, virtually continuous analytical data is provided. Three abstracts detailed the determination of mercury in coal using different approaches.A pressurized digestion and two stage amalgamation coupled with cold atomic absorption spectrometry43 was one proposed route, with a detection limit of 2.5 ng being attained. An alternative was the use of microwave digestion followed by Øow injection-cold vapour AAS and ICP-MS,44 detection limits of 20 and 4 ng g21, respectively, being attained. Possibly the most novel was the hyphenation of the LECO AMA 254 with a Au trap.45 The solid sample was introduced into the LECO system, where it underwent drying, combustion decomposition and a waiting period, followed by thermal desorption in which the Hg was quantitatively trapped on the surface of an Au amalgamator.This was subsequently released for determination by AAS. Characterization of sulfur in coal and coal products was carried out by a total of ten standard and non-standard methods.46 The methods covered the determination of sulfatic, pyritic and total sulfur and/or organic sulfur (by difference) in seven coals and two cokes.The methodology employed was basically the same general procedure, differing only in Æne details, i.e., extraction of sulfate sulfur into dilute HCl, extraction of pyritic sulfur by oxidation with HNO3 after extraction of sulfatic sulfur and the conversion of all sulfur, by heating with Escha's mixture in an oxidizing atmosphere, into sulfate for total sulfur. The outcome of the work indicated that all the methods gave acceptable results; the study has enabled the recommendation of optimized methods.Interestingly, two X-ray Øuorescence methods using standard addition and calibration techniques were reported as unsuccessful. A high pressure, high temperature microwave digestion system was evaluated47 using standard reference materials, one of which was a bituminous coal. Analysis proved that this system results in a more complete destruction of the sample matrix within 7.5 min, which is indeed a great time saver.However, on a safety note, the system used was unable to monitor temperature during the digest programme. This resulted in vessel rupture being common, especially in method development, the vessel being completely destroyed and exhaust fumes being released into the laboratory. Bettinelli et al.48 report the results of a round-robin test (12 laboratories) for the analysis of trace elements in coal Øy-ash and their leachates. The accuracy and precision were acceptable except for Sb and Hg.The greatest source of variability in the Øy-ash analysis was the digestion step because of incomplete digestion. For the leaching tests, the greatest source of variability was the pH of the leaching solutions. Two digestion methods used to extract 17 elements from coal and ash (reference materials) were evaluated.49 The acid digestion method in open vessels using sulfuric acid, hydroØuoric acid, perchloric and nitric acid was compared with a sealed microwave digestion method using just nitric acid. It concluded that the microwave method could not break down silicates, which harbour many trace metals, but unlike the open method can quantitatively extract As and Sb.The effect of reducing sample size from several hundred milligrams to as low as 5 milligrams showed no signiÆcant differences in accuracy providing the total dissolved solids and dilution factors remained constant. Sulfur determination in diesel fuel by EDXRF was reported as a modern and labour saving technique, affording fast and precise determination of sulfur.50 The use of EDXRF analysis with monochromatic excitations enables the rapid determination of trace P, S, Cl, Br and I in fuel oil.51 Detection limits are 4.6, 1.7, 0.7, 0.09 and 0.5 mg g21 for P, S, Cl, Br and I, respectively.Cr Ka 5.41 keV was used to excite P, S and Cl, Mo Ka 17.44 keV was used for Br and W continuous 40 keV for I. Monochromatic excitation of elements affords much better sensitivities. 2.1.3 Oils.As in the previous two sub-sections the theme of trace metal analysis continues into this sub-section, particularly in the analysis of crude oils. The contaminant metals and their relative concentrations can give information regarding the geological origin of the oil and the relative chance of catalyst poisoning and helps oil reÆneries conform to legislative restrictions. The problems associated with the introduction of organic solutions, especially volatile solutions, into an ICP are by now well versed, but the drive to reduce sample preparation to a minimum results in many studies of how best to overcome these problems.Langer et al.52 proposed a method that combines the advantages of electrothemal vaporization, i.e., low sample volumes, the ability to burn off organic matrices before analysis and high sample throughput, with the powerful detection capabilities of ICP-MS.The new approach should yield faster analysis times with lower sample preparation, reducing the amounts of organic solutions in the system. Actual results were not discussed. Other workers53,54 proposed the destruction of the organic matrix via microwave digestion before analysis by ICP-AES and sector Æeld ICP-MS, respectively. The latter used a Finnigan MAT `Element' ICP-MS system, which combines high sensitivity with the capability of high resolution to enable unambiguous determination of major, minor and trace elements to very low levels.Silicon, another known catalyst bed poison, is difÆcult to analyse in crude and other matrices, e.g., diesel fuels, as conventional sample introduction into ICP suffers from species volatilization. Work carried out using a direct injection nebulizer (DIN) for sample introduction is detailed.55 Operating conditions, detection limits and analysis recoveries for Si, Cu, Mg and Zn are given. Several papers received during the review period56±61 recount methods for the analysis of used oil for forensic purposes.The Ænal information gathered is similar for all methods, which vary in instrument set-up, e.g., radial/axial viewing, sample diluents and sample preparation routes. A 600 W capacitively J. Anal. At. Spectrom., 1999, 14, 1937±1969 1951coupled microwave plasma torch (diagram given), with Ar, N2 and air as working gases, has been used for the analysis of aqueous and organic solutions.62 For organic solutions an air plasma was tested because of high background problems with Ar and N2 plasmas.Motor oils were analysed directly, the results obtained comparing favourably with those attained after acid digestion. If this type of system was commercially viable, then there could be some cost saving beneÆts on consumables. The outermost surface of steel sheet consists of a thin oil Ælm, which contains inorganic, organic and organometallic compounds.The characterization of this Ælm is extremely useful, not only technically but environmentally. A comprehensive study on this type of Ælm was carried out using high resolution (HR) ICP-MS.63 The methodology based on ultrasonic extraction and phase separation is given in the form of a Øow diagram. The HR ICP-MS technique gave useful information on total insoluble matter, inorganic (polar fraction) and organic (apolar fraction) compounds. Much effort was put into overcoming the strange behaviour in the plasma when the sample was introduced after USN and desolvation; this was attributed to the presence of substances with very different physical properties.In many countries the recycling and disposal of waste oils is regulated by the metal, halogen and PCB content. In the US, waste oil containing more than 0.1% (m/m) of Cl is considered hazardous waste. The prominent spectral lines for non-metals, i.e., Cl, Br, I, S and P, lie in the vacuum ultraviolet spectral region between 130±190 nm.Wavelengths below 200 nm are absorbed by oxygen and water vapour. The optics of some commercial systems are under vacuum to prevent this: however, these have problems with outgassing and coating of optical surfaces. K. Krenel-Rothensee et al.64 used a nitrogen Ælled optical system to allow element determinations down to wavelengths of 120 nm. Detection limits of Cl, Br, I, P and S were 0.9, 1.6, 0.5, 0.04 and 0.7 mg kg21, respectively. 2.2 Organic chemicals and solvents This section of the review covers analysis of organic chemicals and solvents.Also included is work dealing with determination of organic and organometallic compounds in environmental samples where these are related to industrial processes or products. A summary of work published during the review period is given in Table 2. 2.2.1 Organic chemicals. The analysis of organic chemicals by indirect atomic spectrometry seems to have increased when compared with other years' publications.The determination of tannic acid in tea by indirect FAAS of a Cu complex has been reported.65 Sample (2.5 g) was mixed with 20 ml of H2O and boiled for 20 min before Æltering. The residue was washed with H2O and combined with the Æltrate to give a volume of 50 ml. A portion was then precipitated with 200 ng g21 of Cu2z and 0.1 M ammonium acetate and centrifuged down. Cu was determined in the supernatant at 324.7 nm by FAAS. Calibration was linear from 1±40 mg ml21 of tannic acid, with recoveries of 94.7±102%. RSDs of 3.16% were obtained at the 10 mg ml21 level.A neat combination of ES-MS and ICP-MS for the determination of cobalamins and cobinamides has been published this year.66 Altogether, six cobalamins and cobinamides were determined by HPLC with spectrophotometric, electrospray- MS and ICP-MS detection. A Vydac C8 column (1561 mm id, 5 mm) was used with a 25 mM acetate in methanol±H2O (1 : 1, solvent A) or in H2O (solvent B) as the mobile phases.Gradient elution was used from 20±80% A in 30 min. The ES-MS allowed for the unambiguous identiÆcation of the eluted compounds with ICP-MS for the quantitative determination of Co. Detection limits were 0.01±0.05 mg ml21 for ICP-MS with RSDs of v6.1%. The method was applied to the analysis of pharmaceutical preparations of cobalamins. Another pharmaceutical application has been the indirect determination of berberine hydrochloride via Co with FAAS detection.67 Sample (0.25 g) was dissolved in hot H2O, and diluted to 500 ml.A 2.5 ml portion was mixed with 5 ml of 0.3 M ammonium tetrathiocyanatocobalt, and adjusted to pH 2 with 1% HCl. The mixture was extracted with 10 ml of 1,2- dichloroethane and the organic phase was removed and evaporated to dryness. The residue was treated with HNO3± HClO4 and Co determined by FAAS. The average recovery for berberine hydrochloride was 97.2% with an RSD of 0.4%. The results obtained with this new method compared favourably with standard methods of analysis.There has been some advances in the use of various XRS and XRF techniques in the analysis of a diverse range of organic matrices. An example is the determination of light elements (C, H and O) in organic liquid matrices such as solvents and base oils by EDXRS and principal component analysis (PCA).68 The method is based on a signiÆcant contribution of the light elements to the backscattering of X-rays in the sample.For the present work a Y secondary target in a cartesian geometry was used. The prediction error of the PCA calibration with respect to unknown samples was in the region of 4.0, 30.0 and 26.0 mg g21 for H, C and O, respectively. A semi-empirical method for improved trace multi-element determination in matrices important in toxicology, medicine and agriculture has been reported.69 The method is based on 109Cd radioisotope energy-dispersive X-ray Øuorescence (EDXRF) spectrometry by modelling the dark matrix, estimating the background and scatter to enhance matrix correction and deconvolution of the X-ray spectra using the AXIL-QXAS techniques.The method proved to be very versatile for the analysis of light element matrices with successful modelling of the background and scatter components. A method for the determination of Sr, Zn, Cu and Fe in liquorice by XRF has been developed.70 Samples and artiÆcial standard samples (consisting mainly of MgO, CaO, K2CO3 and NaCl as matrix components) were ashed at 400±600C before pellet preparation.All the elements were determined using Ka spectra with the voltage of the X-ray tube at 40 kV and a current of 20 mA. Linearity was achieved between concentrations of 1±10% with detection limits of 46, 42, 69 and 85 mg g21 for Sr, Zn, Cu and Fe, respectively. RSDs of v8% were obtained and the results compared with those obtained by ICP-AES. In the arena of sample preparation, microwave digestion techniques continue to make advances for the analysis of organic samples.A series of papers on the analysis of traditional Chinese medicines (TCMs) using microwave digestion with ICP-AES and ICP-MS detection have been reported.71±73 Analysis of TCMs have revealed them to be rich in trace elements. These are either introduced as contaminants or active components. Good agreement is reported between HNO3± H2O2 microwave digestion methods and traditional sealed bomb digestions, wet digestion with HNO3±H2O2 and HNO3± HClO4 on a hot-plate.Recoveries ranged from 78±121% for a range of matrices. The analysis of organo- and inorganic mercury in cosmetics by ETAAS has been reported.74 The methods involves the use of ammonium hexachloropalladate±ammonium hexachlororhodate mixed modiÆer. This allows the determination of inorganic Hg, alkylmercury and phenylmercury using a maximum ashing temperature of 920 �C (870 �C for methylmercury).The characteristic mass and detection limit are 59 and 38 pg, respectively, with recoveries in unspeciÆed cosmetics of 97±103%. Other sample preparation reports include the use of ultrahigh pressure and temperature microwave preparation of high molecular weight organics for ICP-AES75 and the effect of digestion temperature on matrix decomposition using a high 1952 J. Anal. At. Spectrom., 1999, 14, 1937±1969pressure asher using HPLC to analysis for organic decomposition products.76 More ES-MS work has been surfacing, speciÆcally a study of the association of pyocyanine (Pyo) with Mn2z in aqueous media.77 Three complexes of Pyo with manganese, namely PyoMn2z, Pyo2Mn2z and Pyo3Mn2z were obtained with ESMS from unbuffered aqueous solutions; however, the results were not consistent with what is expected for metal±Pyo complex formation.The technique does show huge promise for this type of study. Other ES-MS applications include the determination of metals as EDTA complexes78 and the determination of arsenic compounds in biological samples.79 Some interesting applications of 13C : 12C ratio measurements have surfaced this year.A method has been developed for the determination of dissolved organic carbon and it has been applied to chromatographic fractions of heavy metals in humic substances.80 Solutions of fulvic acid fractions (after isolation on XAD-8) were treated with known amounts of 13Cenriched benzoic acid and the 13C : 12C ratios measured by ICPMS.Detection limits of 0.3 mg l21 were obtained and the results were comparable with those obtained from oxidation to CO2 and IR detection. Another application has been the measurement of 13C :12C ratios in amino acids and proteins using a twin quadrupole ICP-MS.81 The instrument was optimized using an Li standard with 13C : 12C ratio precisions approaching counting statistic limits being obtained. For spiked samples the correlation plot of measured 13C : 12C ratio versus the actual 13C : 12C ratio was linear, r~0.9998.A novel technique for the correction of volatility differences between organic samples and standards in organic solutions for ICP-AES and ICP-MS has been reported.82 The technique is based on the measurement of the analyte signal at two spraychamber temperatures. A volatility correction factor is then estimated from a linear correlation between the reciprocal of a correction factor and the relative change in intensity.Tests with organosilicon and organochlorine compounds demonstrate a signiÆcant decrease (from 2±30 times) in error after correction. The technique requires no prior knowledge of the chemical structure of the analyte. 2.2.2 Solvents. It has been reported that the addition of solvents to aqueous solutions has potential advantages to the overall analysis. Cao et al.83 have carried out work to determine the effect of the addition of various types of water-mixed organic solvents to the signal intensity of different ionization potential elements by ICP-MS. They report that the addition of volatile organic solvents such as ethanol, propan-1- ol and acetone reduces the maximum nebulizer gas Øow rate required. Certain solvents, e.g., alcohol, increase the signal intensity of hard-to-ionize elements, e.g., As, Se and Te, although this effect is not mirrored by elements that are easy to ionize.The effect of nitrogen containing solvents is also reported along with the effect of ethylenediamine on the intensity of atomic and ionic lines of Hg.Other workers84 have studied the effect of the addition of alcohol and carboxylic acids to aqueous solutions prior to analysis by ICP-AES. They report that the use of organic solvent diminished the aerosol mean drop size because of the reduction in surface tension. The addition of 3% butanol produced a 40°25% gain in the signal to background ratio: similarly with the use of 20% acetic acid.Detection limits, RSD and sensitivities (tabulated) were improved with addition of organic modiÆer. Solvent extraction and pre-concentration often go hand in hand, for example the determination of As in environmental samples was carried out by FI-HG-AAS following solvent extraction pre-concentration and back extraction.85,86 In this instance AsIII was quantitatively extracted from water at pH 1.5 in the presence of 10% thiourea (masking agent) with 10 ml of 0.2% zinc hexamethylenedithiocarbamate in 2,6- dimethyl-4-heptanone and subsequently back extracted with a slight stoichiometric excess of CuII solution.Total As was determined via the same route after conversion of AsV to AsIII. The detection limit was 8 ng ml21 with recoveries reported as 95.5±99.7%. Similarly, sodium diethyldithiocarbamate was impregnated on a column packed with soft polyurethane foam segments in the pre-concentration of trace elements from water; 10 ml of propan-1-ol was used to elute the elements. An eight-fold pre-concentration was reported.87 Pb was extracted and pre-concentrated from water via the use of a dual-stage pre-concentration system for FAAS using FI on-line ion exchange followed by solvent extraction.88 A detection limit of 0.3 mg l21 was reported, and recoveries of added Pb to tap and rain water gave recoveries of 94±100%.Snell et al.89 evaluated the stability over time of elemental mercury, methylmercury and inorganic mercury species in the following solvents: heptane, toluene and mixed hydrocarbon solutions.Elemental mercury and inorganic mercury(II) were determined using a speciÆc extraction method followed by ICPMS or CVAAS. Methylmercury and mercury(II) were determined by GC-MIP-AES after derivatization with a Grignard reagent. The results showed that signiÆcant losses of mercury species from solution could occur by two pathways: by adsorption on the container wall and by reactions forming mercury(I) compounds.A novel chemometric technique is described by Barnes et al.90,91 which facilitates the use of a single organic solvent matrix standard to calibrate ICP-AES for the accurate determination of trace elements in other organic solvents. Analysis errors arising from the difference in solvent matrix vapour loading and chemical composition between standard and sample are corrected via the use of established correction factors.As mentioned in other sections, the introduction of solvents into ICP can have its problems and many workers have investigated improved ways of introducing organic solvents into ICP. Improved organic analysis using a desolvating MCN with ICP-MS92±95 details the advantages of this approach. The use of a low Øow MCN system incorporating a membrane desolvation step means that the total amount of material used is low, 60 ml min21, giving the sample more time in the desolvator and thus improving the solvent removal.Since the solvent is removed the idea of a universal calibration is mentioned. Arsenic has been determined in organic solvents and wines via the use of micro-scale Øow injection (mFI) ICP-MS. The presence of carbon-containing substances can enhance the As signals and elevate background levels observed in ICP-MS, thus causing potential errors. The errors are reduced by the use of mFI in conjunction with MCN. The calculated absolute detection limit of the mFI-ICP-MS system ranged from 25± 59 fg As, demonstrating its potential for determining As at ultratrace levels.Ar-related interference in ICP-MS when analysing organic solvents precludes the determination of chromium because of the formation of ArC (m/z 52 and 53). The use of a cool plasma to determine Cr in organic solvents is reported;96 the paper gives an overview of the experience. 2.3 Inorganic chemicals and acids This year has seen an increase in the direct analysis of solid samples for industrial measurement applications. Laser ablation techniques and solid sampling ETV methods have both featured strongly in the literature and look set to grow in popularity in the future. As has been the case in receears, speciation has continued to be an important topic of research and some interesting developments in this area have been reported.Numerous applications in which electrothermal vaporization AAS has been utilized as the detection system for trace metal analysis have been reported during the past year.Using a solid J. Anal. At. Spectrom., 1999, 14, 1937±1969 1953sampling technique, Schro»n et al. determined copper, lead, cadmium, zinc and iron in calcium Øuoride and other Øuoride matrix samples.97 The powdered samples were weighed on a microbalance in a boat which was then placed directly in the furnace. Drying, ashing and atomization conditions were optimized for each separate element.Detection limits in the low pg region were achieved for the elements of interest. An interesting approach to preconcentration prior to measurement using ETAAS has been reported for the determination of lead in solutions of NaCl and Na2SO4.98 The dissolved samples were passed through an electrochemical Øow micro-cell (3 ml volume), where lead was electrodeposited by polarization of glassy carbon and platinum electrodes sealed into the cell. In this way, lead could be extracted from the bulk matrix of the dissolved salts.The deposited lead was subsequently re-dissolved into an eluent stream directed through the cell, and transported to the furnace. The furnace comprised a transversely heated atomizer and was equipped with Zeeman background correction. A detection limit of 1.2 pg ml21 was reported for a 3 min preconcentration step and the process was reported to be interference free. The measurement precision (at 100 pg ml21) was around 5% (relative standard deviation, n~12), which is acceptable at this concentration level.On-line electrochemical matrix separation and preconcentration techniques are an interesting alternative to the more traditional column-based methods, and may prove to be even more viable than column methods for routine applications in the future. An assessment of the potential toxicity and mobility of heavy metals in industrially contaminated land, based on the BCR three-step sequential extraction procedure, was the focus of a study carried out by Davidson et al.99 Eight elements, including cadmium and lead, were studied using ETAAS detection.It was found that certain elements, in particular lead, were not reproducibly extracted from duplicate samples of contaminated soil and also that the amount of metal extracted via the sequential procedure did not agree well with the values measured from samples pseudo-digested with aqua regia. At a sampling depth of 65±85 cm at the contaminated site, less than 0.2% of the total Pb was found to be present in an acid soluble or exchangeable form.The study underlined the importance of considering metal speciation when monitoring potentially toxic metals in contaminated land samples. Lead was also the element of interest in a study of calcium drug samples, using a slurry sampling technique.100 The drug samples were ground to a particle size of around 3 mm and homogenized in solution by agitation in an ultrasonic bath, prior to application to the molybdenum tube atomizer of the ETAAS instrument.Use of such a small particle size was found to be necessary to facilitate accurate quantitation of lead by external calibration with lead standard solutions, matrix matched by addition of CaHPO4 or CaCO3. At larger particle sizes, considerable variation in the observed signal was reported. Thiourea was used as a matrix modiÆer to reduce the effect of matrix related interference on the lead absorption signal.Good agreement between the results obtained for slurried samples and samples digested in acid was reported. In addition, the furnace was operated under an argon±hydrogen atmosphere which prolonged the lifetime of the molybdenum atomizer by a factor of 20. This procedure offered a more direct way of measuring lead in the drug samples but suffered from the disadvantage that the samples required grinding prior to analysis, which increased the overall analysis time compared with simply digesting the samples.Analysis using Øame AAS as the detection system has continued to feature in the literature this year. The determination of Te in industrial grade sulfuric acid has been reported.101 The samples were diluted 1 : 1 with water, then subjected to a somewhat complex series of preparation steps aimed at separating the Te from the sulfuric acid matrix, culminating in a precipitation of the Te with NaHSO4. The precipitate was re-dissolved with dilute nitric acid and Te was determined by Øame AAS at 214.3 nm.A linear, standard additions calibration across the range from 0.125 to 0.25 mg l21 was reportedly achieved. This approach also yielded Te recoveries of between 94 and 97%, and was found to be tolerant to levels of As up to 15 mg l21 and selenium up to 3 mg l21. The procedure reported did offer advantages over simply diluting the sulfuric acid to concentrations manageable by the AAS instrument, but was quite time consuming.Flame AAS detection, using a slotted quartz tube, has also been employed in an elegant procedure for measuring Pb in industrial silicon.102 In this work, pulverized silicon samples were heated with a mixture of HNO3 and HF, then evaporated to fumes with HClO4. The residue was reconstituted with dilute HNO3 and introduced to the AAS instrument via a high efÆciency nebulizer, using a pulsed injection sampling technique to reduce the amount of sample entering the instrument.This technique gave a detection limit of 6 ng ml21, which was reported to be a 30-fold improvement compared with conventional Øame AAS. Analyte recoveries were acceptable, ranging from 92 to 104%. Atomic Øuorescence (AFS) detection was utilized for the determination of As in antimony trioxide.103 This analysis suffers from a considerable interference from the antimony trioxide matrix, so it was necessary to develop a procedure to separate the arsenic.This was achieved by reducing the antimony trioxide to stibine, with arsenic being reduced to arsine at the same time. The gaseous mixture was passed through a solution of KMnO4, whereupon stibine decomposed at a faster rate than arsine. As a result, the bulk of the antimony matrix remained in the permanganate solution while the arsine passed on to the detector. The detection limit for arsenic was stated to be 2.5 mg kg21, with a measurement stability of around 7% RSD at the 400 mg kg21 level.An arsenic recovery of 104% was reported for spiked samples, and the method was stated to meet the analytical requirements. The method developed was relatively simple to perform, but for routine practical purposes the detection limit and measurement precision may need to be improved. Several interesting articles regarding applications based on ICP-OES detection have appeared in the literature this year. A modiÆed glass concentric nebulizer, based on the Meinhard and LB designs, has been developed for the analysis of high salt content samples by ICP-OES.104 This nebulizer was reported to be capable of nebulizing a saturated NaCl solution [26.5% (m/v) at 25 �C] for more than 2 h without clogging.The signalto- background ratio (SBR) and detection limit (DL) performance achieved, for a range of transition metals and alkaline earth elements, was also reported to be superior (by up to a factor of 2 for both the SBR and the DL) to that of the conventional Meinhard design, although, the effect of the high salt content in terms of analyte signal suppression/enhancement was not described.Further results from the enclosed ICP-OES instrument, described in this section of last year's review, have been reported. In the most recent work the device has been used for the determination of Fe and Ni in electronic grade chlorine.105 The plasma discharge (50% Ar, 50% Cl2) was generated in a sealed quartz chamber, at 40.68 MHz and 1.1 kW forward power, with a total gas Øow rate of 200 ml min21.The instrument was calibrated for Fe and Ni by adding either Fe(CO)5, ferrocene or nickelocene through appropriate permeaon tubes at 80 �C. Detection limits, under Øowing conditions, of 290, 20 and 9 pg ml21 were given for Fe in Fe(CO)5, Fe in ferrocene and Ni in Ni(CO)5, respectively. The within and between day signal stability of the system was reported to be around 4% and 6% relative standard deviation (RSD), respectively, for Fe, but somewhat poorer (around 18% RSD) for Ni.A microwave plasma emission source has been 1954 J. Anal. At. Spectrom., 1999, 14, 1937±1969used for the determination of chloride in water samples, after continuous Øow oxidation of the chloride to chlorine gas.106 In this work, water samples were mixed off-line with H2SO4 to a Ænal acid concentration of 9 M, then oxidized on-line with 30 mM KMnO4. The chlorine gas evolved was separated with a gas±liquid separator and carried to the plasma, via a container of concentrated H2SO4, by a stream of helium.Once in the plasma, chlorine was measured by its emission lines at 479.454 and 481.006 nm. Using these two lines, detection limits of 7 and 12 ng ml21 were achieved with a typical measurement precision of around 2.5% (RSD) at the 0.5 mg ml21 level. The results obtained for chloride in pond and river waters compared well with those achieved using ion chromatography, suggesting that this approach may be practical for routine analysis of these types of samples, although cost could well be an issue.The potential of ICP-OES for measuring non-metals was explored by Heitland et al.107 An axially viewed ICP-OES instrument, conÆgured to monitor vacuum-UV emission lines, was used to measure halogens, sulfur and phosphorus in aqueous and oil based samples (diluted with kerosine). Detection limits ranging from 3.5 ng ml21, for S, to 450 ng ml21, for Br, were achieved in aqueous solution, while in the oil samples the corresponding Ægures were 70 ng ml21 and 1400 ng ml21 for Br and S, respectively.Recovery results for Cl in a commercial organic material (diluted with kerosine) were between 98 and 102%. This year has again seen a growth in the number of papers discussing applications using ICP-MS detection, with the increasing use of solid sampling techniques being of particular signiÆcance. The determination of ruthenium in photographic emulsions and Ælms, using ETV-ICP-MS, has been reported.108 Addition of trace amounts of precious metals, such as Ru, to photographic emulsions has a beneÆcial inØuence on the light sensitivity of these materials.The quality of the emulsions produced depends on the concentration of these elements. The emulsion samples were treated by either drying them at 105 �C or by converting them into colloidal solutions in warm water or dilute nitric acid, before being directly applied to the furnace.Using an optimized furnace temperature program, the authors were successful in selectively vaporising up to 90% of the Ag matrix of the samples before atomising the Ru and the Ir internal standard. The absolute limit of detection for Ru was reported to be 1 pg, and the results obtained showed good agreement with measurements made by conventional pneumatic nebulization ICP-MS. The direct solid sampling approach involved minimal sample preparation, consequently leading to an overall increase in sample throughput.A method for the determination of Li, Pb, Cd and Fe impurities in high purity sulfamic acid samples, based on isotope dilution ETV-ICP-MS, has also been reported this year.109 In this work, sulfamic acid solutions were spiked with 6Li, 57Fe, 111Cd and 206Pb enriched isotopes and left to equilibrate, prior to analysis. The samples were atomized in graphite furnaces (modiÆed with Pd) and on tungsten ribbon atomizers.The impurity concentrations found were in the low ng g21 range for all the analytes selected, and were typically found to be around twice the blank level. No differences in performance were identiÆed between the graphite furnace and tungsten ribbon atomizers. Ion chromatography coupled to ICP-MS is now a well known technique for elemental speciation. This year, a method which uses this approach has been reported for the simultaneous speciation of eight halogenides and oxyhalogens in drinking water samples.110 Samples were measured before and after disinfection, to determine whether species conversion occurred during the disinfection process.Iodine and chlorine containing species were found to be unaffected, but bromide concentrations were seen to be reduced in the disinfected samples. Detection limits of 500, 10, 0.1 and 0.2 ng ml21 were achieved for the chlorine-based species, bromine-based species, iodide and iodate, respectively. A major beneÆt of ICP-MS is its isotopic measurement capability.This feature of the technique was the focus of a study by Briche et al. in which Pt isotope ratios in synthetic isotope mixtures of Pt were studied.111 Five synthetic Pt isotope mixtures, ranging from 0.1 to 10 for the isotope amount ratio 196Pt : 195Pt, were prepared from metrologically prepared solutions of two isotopically enriched Pt materials, made up from enriched Pt powders. These mixtures were analysed by quadrupole ICP-MS, to determine the mass discrimination factor, and to subsequently characterize their non-certiÆed isotopic compositions.The correction factors required to correct the 196Pt : 195Pt isotopic ratio measurements of each of the Æve mixtures agreed within 0.2%. Once fully characterized, these mixtures were suitable for calibrating Pt isotopic ratio measurements on other mass spectrometer systems. Laser ablation ICP-MS continues to be a popular analytical tool for geological sample analysis.Platinum group elements and gold were measured in a range of geological reference materials, using UV LA-ICP-MS.112 The samples were heated with nickel sulÆde to produce Ære assay buttons for the analysis. This classical procedure has been used for many years to preconcentrate the PGMs and gold from geological samples. The analytical precision achieved with sample was typically in the 10% relative standard deviation region although, in general, good to excellent agreement between the measured and certiÆed analyte concentrations was reported to be obtained.Detection limits based on 10 s integration times were stated to be v10 ng g21 for the analytes of interest, although this remains somewhat optimistic for most laser ablation analyses, for which practical detection limits are somewhat higher. New sampling approaches for mass spectrometry have been at the forefront of developments in this area of analysis. Laser ablation TOFMS has been used for the measurement of deuterium and hydrogen in zirconium containing 2.5% (w/w) niobium.113 Samples were Ærst ablated with a Q-switched Nd:YAG laser, then, after a 0.9 ms delay, the plume of ablated material was subjected to a pulse from an XeCl excimer laser, which ionized 1H and 2H by a resonance ionization process.The technique was used to perform surface proÆling of the 1H and 2H concentration distribution in the zirconium samples. Isotope dilution thermal ionization mass spectrometry (IDTIMS) has been used to quantify Cr, Cd and Pb in photographic AgCl emulsions.114 Isotopically enriched spikes of the analytes of interest were added to the solid emulsions, which were then dissolved in dilute ammonia to facilitate isotopic equilibration. The silver matrix was precipitated as AgCl from this solution.The supernatant solution was treated with H2O2 and HNO3 to decompose organic material carried through the procedure from the original emulsion samples.However, this was found to be insufÆcient to completely remove the organic matrix so the analytes of interest were removed from solution by electrolytic deposition onto Pt electrodes. The deposited metals were re-dissolved using a concentrated H2O2±HNO3 mixture, evaporated to dryness, reconstituted with dilute HNO3 and Ænally loaded onto Re Ælaments for the TIMS measurements. Detection limits ranged from 0.4 ng for Cr to 4 ng for Pb. Four emulsions were analysed and found to contain very low Cd levels (v3 ng g21), higher Cr levelrom 40 to 100 ng g21) and widely varying Pb concentrations (from 10 ng g21 to 6 mg g21).The results for Pb and Cr were cross-validated with quadrupole ICP-IDMS results and found to agree well. Speciated isotope dilution mass spectrometry has been applied to the study of chromium species in water samples.115 It is known that the speciation of Cr solutions can change over time because of the reduction of CrVI to CrIII, thereby leading to inaccurate interpretation of the species present in the original sample.The aim of this work was to improve the accuracy of J. Anal. At. Spectrom., 1999, 14, 1937±1969 1955the Cr speciation measurement by introducing isotopically enriched spikes in Æxed oxidation states, i.e., 50CrIII and 53CrVI to the samples. These samples were then analysed over a period of time using HPLC to separate the species prior to MS detection.By studying the changes induced in the isotopic composition of the separated Cr species, by the reduction of CrVI to CrIII, an accurate correction for this reduction could be made (up to 80%). This elegant technique offers the potential to improve the quality of a wide range of speciation measurements in the future. Finally, there have been a large number of articles describing the use of X-ray Øuorescence detection this year. The technique has been used to measure transition metals, halogens, phosphorus and sulfur in amino acid and nucleotide sample spots on thin-layer chromatography (TLC) plates.116 Sections of the TLC plates were analysed directly without further pretreatment.The study of chemical speciation has become a major research topic in recent years. It has long been known that the characteristic X-ray emission lines of elements are changed by the chemical state of the element and these changes can be used to speciate the element of interest.This feature of X-ray analysis has been exploited for examining vanadium speciation in a range of vanadium compounds, using energy dispersive XRF.117 Energy dispersive XRF was used in this work because, in contrast to wavelength dispersive XRF, this technique is capable of simultaneously detecting a large number of X-ray lines from several elements, as well as being more efÆcient and simpler to operate. By studying two particular X-ray line groups in the spectra of the vanadium compounds, the authors were able to distinguish between metallic V, VCl3, NaVO3 and Na3VO4, but could not distinguish between VO2 and VCl3.A Æeld portable energy dispersive XRF device was used to characterize liquid hazardous waste.118 Representative analysis of this type of material is challenging because the samples are rarely homogeneous and may have a complex composition. In this work, detection limits for the elements of interest were around 10±20 mg kg21. The samples were successfully analysed for a range of metals, after a simple sample preparation step. 2.4 Nuclear materials The application of inductively coupled plasma mass spectrometry for elemental and isotopic analysis has continued to grow, the major change being the increased number of reports involving sector Æeld instruments. The general themes remain unchanged and include the determination of long lived radionuclides, isotopic abundance or ratio measurements and the development of non-standard sample introduction methods.A comprehensive, but rather similar, series of papers covered the use of direct injection, microconcentric, ultrasonic and crossØow nebulizers with both quadrupole and sector Æeld ICP-MS instruments. Flow injection and normal aspiration modes were reported and various combinations of these experimental techniques were applied to the determination of the total and isotopic composition of various actinides.119±122 The coupling of ICP-MS and HPLC123±126 or Øow injected micro-columns127 to provide on-line separations were described.Off-line sample separations remain important and although the use of extraction chromatography is growing, a small effort involving liquid±liquid separations was reported (e.g., references 128 and 129). As a general comment on solvent extraction techniques, the generation of mixed organic laboratory wastes is discouraged within the nuclear industry. The use of mass spectrometric methods, i.e., ICP-MS, TIMS and SIMS, as an alternative to classical radiometric methods for Pu and U bioassay has been the subject of signiÆcant interest.130±134 Thermal ionization mass spectroscopy was reported to give a 40-fold improvement in the average measurement uncertainty of 239Puz240Pu when compared with a classical radiochemical ±a-spectrometry methodology.134 Similarly, the application of ICP-MS, including high capacity interface pumping (`Soption') and ultrasonic nebulization, for U and Pu bioassay was reported in some detail.130 The U bioassay was suitable for compliance testing (2 mg total in testing period) and for estimating occupational exposures via the determination of 236U and 234U:238U.The detection limit for Pu bioassay was estimated at 2±3 fg. Further reÆnement was required to reduce matrix effects and improve recoveries. Secondary ionization mass spectrometry was applied to U and Pu bioassay.131 After puriÆcation, U and Pu were concentrated by extraction onto a polypyrrole Ælm and this Ælm formed the target for SIMS.Detection limits for U and 239Pu were quoted as 100 pg dm23 and 10 pg dm23 (23 mBq dm23), respectively. For Pu bioassay, this detection limit is several orders of magnitude away from that required for routine monitoring purposes. These methodologies concentrate upon dose contributions from 239Puz240Pu and, in selected cases, this may be sufÆcient. However, if classical radiometric methodologies for Pu bioassay are to be supplanted universally by mass spectrometric techniques, the important potential dose contribution from 238Pu cannot be ignored.The determination of 238Pu, at the levels required for bioassay, is a massive challenge for mass spectrometry. This challenge demands both improved instrumental selectivity (resolution of 238Pu from ubiquitous 238U) and improved detection limits. Techniques such as resonance ionization mass spectrometry135 have the potential to fulÆl this requirement but this remains an unrealised potential.The use of advanced techniques such as accelerator and resonance ionization mass spectrometry continues to generate a steady undercurrent of interest. An initial study for the determination of 99Tc in environmental samples by AMS yielded detection limits of 0.5±0.6 pg or ca. 0.3 mBq.136 Metallic Rh was used as a carrier, an aqueous Rh standard solution was added to the sample, homogenized and the sample co-precipitated on the metallic carrier by the addition of a reductant (NaBH4).The carrier solution was puriÆed prior to use by heating with H2O2 to volatilize interfering Ru. The AMS was operated at a terminal voltage of 9 MeV, with a carbon foil stripper element and ion detection by projectile X-ray emission from a Sc foil. Some interference from 99Ru was observed but, if a puriÆed Rh carrier was used, this could be resolved mathematically. The highest ion yield was at the z12 charge state but interference from sulfur, possibly as 63Cu36S, was observed in environmental samples.This was attenuated by monitoring of the z10 charge state. The determination of 129I by AMS continues to be of interest and a carrier free method for determining 127I : 129I in environmental samples was proposed.137 This was based upon depositing iodine directly onto an Ag powder. The slow evolution of RIMS for the determination of Pu continues135,138,139 but little real progress has been made this year.Detection limits for RIMS (106±107 atoms) are superior to conventional alpha-spectrometry for the longer lived Pu isotopes but are inferior for the shorter half-life isotopes. As discussed previously, the replacement of classical radiochemical analytical techniques in environmental and biological monitoring programs is a demanding task. The application of RIMS to the biological and environmental monitoring task is obvious and has received some attention.135 However, it is believed that signiÆcant advances in RIMS are required.The probable aim of these developments should be to provide a 102±103 improvement in detection limits coupled to a proof of selectivity for 238Pu over 238U. This would allow RIMS to compete effectively with alpha-spectrometry as an analytical technique within comprehensive biological and environmental monitoring schemes. A number of reports were concerned with X-ray techniques 1956 J.Anal. At. Spectrom., 1999, 14, 1937±1969and included an overview of the application of electron probe microanalysis to post-irradiation examination of fuel.140 The use of biological shielding, in conjunction with shielded detectors, allowed the investigation of fuel sections with an activity of up to 75 GBq. Careful sample preparation, and especially decontamination, was used to avoid carryover of hot particles from the sample preparation caves to clean laboratory areas.A number of problem areas were addressed, e.g., the use of incorrect standards for some elements, X-ray line interferences and uncertainties in the matrix correction procedure. Despite these issues, it was considered that EPMA was capable of delivering chemical composition information of fundamental importance to the understanding of the in-pile behaviour of fuel. As an example of the use of EPMA for post-irradiation examination of fuel, an independent report considered a combination of XRF and EPMA for the study of Æssion gas in the rim region of high burn-up fuel pellets.141 The use of X-ray techniques for the determination of U and Pu in fuel was reviewed and included topics such as X-ray emission, Øuorescence and absorption edge densitometry.142 A comparison of TXRF and ICP-MS for the analysis of reactor waters included a discussion of the radiological controls necessary for a successful TXRF procedure and the use of internal standards.143 Detection limits in the low pg range were reported for most analytes of interest.The combination of m- XRF, Raman and infrared microscopies was shown to be a powerful experimental approach for the characterization of heterogeneous actinide contaminated materials.144 For example, plutonium contaminated particles were detected by m-XRF and identiÆed as PuO2 by Raman spectroscopy. 3 Advanced materials 3.1 Polymeric materials and composites A variety of techniques have been reported for surface analysis and depth proÆling of thin Ælms.These include the normal suspects such as secondary ionization mass spectrometry, Auger electron spectroscopy, X-ray photoelectron spectroscopy, etc. The improvement of depth proÆling resolution is a universal goal within surface analysis and grazing incidence techniques offer one route forward. For example, grazing incidence SNMS, with post-sputtering laser ionization, was applied to the study of multilayer structures of InGaAs in InP and compared with SIMS and AES measurements.145 A 10 keV Arz beam, at an incidence angle of 77�, gave better resolution than that observed with AES (1 keV Arz, incident at 70.3�, sample rotated).However, distortions in the In proÆle at layer interfaces, observed with SIMS (2 keV O2 z beam, incident at 81�) were not observed with the SNMS technique. A review of surface analytical techniques for thin Ælms gave examples of the use of AES, XPS and SIMS.146 The application of X-ray techniques for the authentication of works of art was discussed in terms of the type of information derived and its evidentiary qualities.147 Pigments on late medieval manuscripts were investigated using TXRF.148,149 The pigment was sampled by rubbing with a cotton bud.This removed sufÆcient pigment for the analysis without damage to the manuscript. The process yielded information upon the relative elemental abundances within the pigments. The thickness and elemental composition of pigment multi-layers were determined by variable incidence PIXE.150 The painting was tilted about an axis perpendicular to the incident beam whilst maintaining a constant detection geometry.The peak areas of the detected elemental responses were normalized against back-scattered proton intensity and plotted against tilt angle. The Ætted data points yielded semi-quantitative information about the thickness and composition of the pigment layers.Direct solids analysis of polymers remains a topic of much interest. Laser ablation techniques,151±157 glow discharge158±160 and solid sampling ETV161±165 have been investigated. The various laser ablation techniques, although well suited to a laboratory environment, are difÆcult to adapt to process environments. The exception to this is laser induced breakdown spectrometry, and this technique has been applied to the study of pigments and binders in paper coatings.154 The plasma was formed by focusing a pulsed XeCl excimer laser (dia.~100 mm, irradiance~0.3 GW cm22) on to the sample surface at normal incidence and at atmospheric pressure.Linear correlations between LIBS signal, coat weights and binder contents were obtained. QuantiÆcation of Si and Ca was aided by a normalization procedure. This correction was based upon plasma temperatures derived from ionic and neutral Mg emission. The products of the laser ablation of polyethylene and PVC products, containing inorganic and organic forms of Ca, Ti and Sn additives, were characterized in terms of particle size, physical and chemical form.156 Ablation was performed with a Q-switched, quadrupled Nd:YAG laser (266 nm, 5 mJ, 5 ns pulse at 10 Hz).The most signiÆcant result was that the physical form of C in the aerosol was different from that of the analytes of interest. It was suggested that the entrainment and transport behaviour of the C containing species would therefore be different from that of these analytes. This would tend to invalidate the use of C as an intrinsic internal standard for the analysis of polymers by laser ablation.Radiofrequency glow discharge mass and atomic emission spectrometries were applied to the analysis of bulk and thin Ælm polymers. The most interesting capability of the rf-GD source, reported in this work, is the duality of the ionization produced, i.e., both molecular and atomic ions.166,167 Relative fragmentation patterns were obtained for a series of Øuoropolymers and demonstrated the capabilities of the technique for the determination of polymer composition.167 Ion beam currents were reported to be several orders of magnitude greater than with the equivalent SSIMS system and thermal degradation of the target was reduced by cooling with an LN2 cryogenic plate.The extension of this technique to depth proÆling was demonstrated for an automotive paint panel.166 The ability to proÆle multi-layers was demonstrated by the resolution of clear coat (CH3 z,C2H4 z), base coat (Tiz), primer coat (CH3Oz) and substrate (Alz).The rapid identiÆcation of plastics in recycling plants is of growing importance and the application of various techniques was discussed.168 X-ray absorption and Øuorescence, in conjunction with molecular spectroscopy (MIR, NIR), have been demonstrated to be useful on an industrial scale for the sorting of plastic waste. A number of other techniques are suitable for this task, but are still in the preliminary testing stages, e.g., LIBS. 3.2 Semiconductors and conducting materials The determination of trace contaminants in Ga/As materials have received some attention this year. A variety of mass spectrometry techniques have been used for the determination of ultra-trace contaminants in gallium arsenide.169 Samples of GaAs were dissolved in high-purity HNO3±H2O2 and the trace elements determined by ICP-MS and ICP-AES.Results from SIMS, plus these two techniques, were used on artiÆcial spiked standards to obtain the relative sensitivity coefÆcients for the elements by spark-source-MS, rf glow discharge MS and laser ablation MS, which were then used in the analysis of GaAs samples. Matrects in ICP-MS were reduced by complete matrix separation with a Cl2±Ar (1 : 5) stream at 280 �C. Recoveries for 24 elements were close to 100% except for Sn and Ta. Detection limits were in the low ng g21 range.The analysis of Zn and B in undoped and Zn-doped gallium arsenide single crystals by rf-SSMS and TIMS has been reported.170 The accuracy of the rf-SSMS measurements is J. Anal. At. Spectrom., 1999, 14, 1937±1969 1957Table 3 Summary of analyses of advanced materials Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. POLYMERIC MATERIALS AND COMPOSITES– Mn Li secondary cell cathode materials XAFS;–;– Dynamic structural behaviour of Mn in Li±Mn spinels studied 366 Ni Thin Ælm polymer on Ni coated substrates TXR, AFM;–;– Surface roughness determined by angle dependent TXRF and AFM 367 Ti Ti nitride layers XRF Grazing incidence XRF used to analyse titanium nitride layers produced by reactive sputtering with different working atmospheres 368 Various Thin Ælms X-ray spectrometry Variable incidence excitation with X-ray or ion beam used to study sensitivity of thin Ælm analysis by X-ray spectrometry.Mathematical description of process described 369 Various Polymer coatings on steels RF-GD-AES Quantitative depth proÆling.Correction for effective power and voltage in discharge applied 370 Ti Ti and Hf oxide Ælms on silicon substrates EPMA Data treatment approaches to determination of oxide layer thickness by EPMA compared. Results compared with reference techniques 371 N N doped ZnSe thin Ælms SIMS Films prepared by MOCVD with nitrogen triØuoride as co-reactant and source of nitrogen 372 Pt Al, Zr XPS, GD, AES; –;– Thin Ælms characterized for corrosion and interdiffusion studies.Aspects of bulk and interface reactivity differentiated 373 Mg GaN SIMS Mg dopant in epitaxial layers studied 374 Various Si±Ge multilayers SIMS Layer contamination studied by SIMS 375 Ir Electrode materials for chlor-alkali industry SIMS Distribution of Ir and Ta oxides on Ti substrates determined 376 Various CdS Ælms EPMA, XPS, SIMS;–;– Analysis of impurity precipitates in CdS Ælms grown by chemical bath deposition 377 Ta Si SIMS Multi-layered thin Ælms of tantalum oxide and silica on a Si substrate proposed as depth proÆling standard for SIMS 378 As HgCdTe SIMS As incorporation into HgCdTe layers studied by SIMS 379 Various Si(12x)Nx :H Ælms SIMS Elemental distribution over Ælm thickness determined by SIMS 380 Sn In±Sn oxide Ælm Spark AE Sample (60 mg) with a graphite support fabricated into an electrode for emission spectrometry. Sn : In ratio determined 381 Various Ti Ælm on AlN ceramic substrate SIMS Depth proÆling by SIMS to study effects of manufacturing parameters on interfacial composition 382 C, N Carbon nitride thin Ælms on Si substrates SIMS, SEM-EDAX; –;– Films characterized by a variety of atomic and molecular spectroscopies 383 N Si oxynitride Ælms SIMS, ARXPS;– ;– Concentration, spatial distribution and local chemical bonding of N determined 384 Various Ferroelectric thin Ælms SIMS Elemental depth proÆles determined by SIMS 385 Various MR media SIMS Depth proÆle of C overcoated CoCrTa/r thin Ælms 386 Co, Ti, Si Co/Ti-silicide Ælms in Si substrate TXRF Novel technique of line scan TXRF across bevelled section produced by ex-situ ion beam sputter etching 387 Cd Wall paint AAS;ETV;– Samples digested with HNO3, diluted to 0.5% HNO3 and Cd determined by ETV-AAS (ash :~600 �C, atomize~1900 �C) 388 Zn Polymerized rosin FAAS Sample dissolved in ethanol and Zn determined at Zn I 213.9 nm line with air±acetylene Øame 389 Pb Paint XRF Dedicated, portable radioisotope XRF designed for determination of Pb in paint 390 Various, Sb Polyester Ælm, painted panel MS, LA;ICP;S Application of `low energy' ablation (10 mJ at 1064 nm).Difference response factors obtained for nitrocellulose and alkyl resin based paints 391 P, Ti, Co, Mg Polymers MS, LA;ICP;S Solid standards prepared for various polymers (ABS, PBT, polypropylene, polycarbonate/PBT blend). Results from LA showed good agreement with digestion based method 151 Various Polymer MS, LA;ICP;S Additives, impurities and catalyst residues determined.Depth proÆling and elemental mapping applications discussed. Nitrogen added to reduce interferences 152 Various Polymers MS, LA;ICP;S Application of LA-ICP-MS to analysis of competitor materials and identiÆcation of different polymers used in manufacturing plants discussed 153 Various Filled polymer Ælms MS, LA;ICP;S Semi-quantitative analysis application. Results compared with an accepted digestion procedure 155 Various PET MS, ETV;ICP;S Matrix removed by careful application of multi-step heating program. Sr used as internal standard.Good agreement with XRF reference values obtained. Calibration achieved using either single point standard addition (aqueous standard) or external calibration (solid standard) 161 Sb PVC AA;ETV;S Solid PVC (2.5±3.5 mg introduced into pyrolytic graphite tube. Drying, pyrolysis and atomization temperatures were 120 �C (30 s), 800 �C (30 s) and 2000 �C (1 s), respectively.Calibration obtained against aqueous standards. Analysis suitable for screening purposes for samples containing w2.5% Sb 162 1958 J. Anal. At. Spectrom., 1999, 14, 1937±1969Table 3 Summary of analyses of advanced materials (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref. Pd Aliphatic polyketones MS, ETV;ICP;S Matrix removed by careful application of multi-step heating program.Ir or Ar2 z used as internal standard. Good agreement with XRF reference values obtained. Calibration achieved using either single point standard addition (aqueous standard) or external calibration (solid standard). Method LOD~20 pg (20 ng g21), blank limited, attributed to Ir internal standard. Instrumental LOD~1 pg 163 Sb Polyester MS, ETV;ICP;S – 164 Ru Photographic materials MS, ETV;ICP;S Emulsions taken to dryness at 105 �C.No preparation required for photographic Ælm. ETV temperature program optimized to remove Ag matrix prior to vaporization of analytes of interest. Calibration obtained by single point standard addition. LOD~1 pg 165 Sb PET AAS;ETV;L Material extracted by reØuxing with aqueous ethanoic acid. Supernatant Æltered and diluted. Spike recovery~92±98% 392 Various Polyethylene±polypropylene blend ICP;AES;L High pressure digestion of polymer blend in nitric acid. Temperature program~step to 80 �C, ramp to 160 �C (30 min), step to 280 �C, hold for 90 min, step to 0 �C 393 Various Waste materials ICP;AES;L Optimization of microwave digestion procedure.Three acid mixtures used: (a) HNO3±HCl±HF; (b) HNO3±HCl; (c) HNO3±HF±H2SO4. Boric acid used to complex Øuoride. Most suitable reagent was HNO3±HCl±HF 394 Ti Flame retardant wool AAS;ETV,FAAS;L Sample washed, dry ashed in Pt at 1103 K, extracted with concentrated H2SO4, taken to fumes and then fumed three times with 30% v/v H2SO4.Ti was determined at the 364.4 nm line with D2 background correction and atomization with either an ETV or nitrous±acetylene Øame. LOD~0.84 and 7.4 mg g21 for ETV and Øame, respectively 395 Various Synthetic and natural Æbres SSIMS Imaging SIMS used to identify and map pesticide and detergent residues 396 Halides Combinatorial chemistry solid substrates (polystyrene beads) SEM, EDAX;–;– Beads Øattened and held in silicon wafer bead press. Attachment of various monomers to substrate demonstrated for several authenticated library compounds 397 SEMICONDUCTOR MATERIALS– C Si AE;LIBS;S As in text 173 Cu Si AMS;–;S AMS was used to determine levels of 10B, 14C and 127I to their stable isotopes to levels as low as 10±16 398 P Si MS;ID-ICP;L Si was decompO3±H2SO4.The P was converted to molybdophosphate and collected as an ion pair with dodecyltrimethylammonium bromide before analysis by ID-ICP-MS 399 Various GaN MS;LA-ICP-ToF;S Work concentrated on trace analysis of Si solar cells, CVD grown diamond substrates and GaN.Method proved cheap and quick 400 Various Si AE;LIBS;S LIBS was used to determine the distribution of trace metals. Three dimensional distribution maps for Cu, Al and Ca were obtained 401 Various Si MS;ToF-SIMS;S Metallic impurities were determined with DLs ranging from 661028 to 761027 atoms m22 for Fe and K, respectively 402 Various Si MS;LA-ICP;S Si was cleaned by ultrasonic washing and degreased by trichloroethylene, acetone and methanol before analysis with a Nd :YAG LA-ICPMS system 343 Various H3PO4 MS;ICP;L The use of resolutions w8000 enabled the analysis of Ti, Cu and Zn to be resolved from POn interferences.Calibration issues were addressed 336 Various GaAs SMS;rf-SS;S GaAs single crystals were analysed by rf-SSMA after calibration with charged particle activation analysis 403 Various GaAs AE;F, ICP;L AA;F;L As in text 171 Various Process chemicals MS;ICP;L HR-ICP-MS gave DL v1 pg ml21 for all metal species.Positive blanks were overcome by use of Pt cones and inert sample introduction system 404 Various (4) Process chemicals MS;ICP;L The validation of the methodology concentrated on elimination and identiÆcation of blank levels for Ca, Na, K and Fe at the sub-pg ml21 level 405 GLASSES– Al Glass CRM ICP;AES;ETV Low temperature vaporization of 8-quinolinato complex from W boat at 1000 �C. LOD~0.12 ng.ZrIV used as matrix modiÆer 406 Various High level glass waste form ICP;AES;L Si and B determined after sodium peroxide fusion. Fused mass taken up in hot water and acidiÆed with HCl. Remaining analytes (Li, Na, Mg, Al, P, Cr, Fe, Ni, Sr, Zr, Mo, La, Ce, Nd and U) determined after a complex, multi-stage acid digestion procedure including HF±HClO4, repeated HF±HNO3 evaporations and Ænal digestion of the salt cake in HCl 364 Various High purity quartz ICP;MS;L Sample decomposed with HF vapour in a closed vessel. Limits of quantiÆcation ca. 10±6±10±8% 407 Various Glasses AES;GD;– Bulk analysis performed using glass CRM as calibrants. Depth proÆling performed after leaching in dilute HCl or humic acids 408 Various Powdered glasses AES;GD;– Powdered samples (ca. 0.2 g) pressed into cathodes without addition of conductive substrate. Internal standard~Si I 288.2 nm, discharge conditions~ 30±35W at 4±6 Torr. Validated against NIST 89 409 J. Anal. At. Spectrom., 1999, 14, 1937±1969 1959Table 3 Summary of analyses of advanced materials (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref.CERAMICS AND REFRACTORIES– B Silicates MS;ICP;L Rock powder (50 mg) was soaked in mannitol, mixed with10B-enriched spike and 30 M HF. The sample was evaporated to dryness and 0.5 M HF added to recover the B. LOD was 0.02 ng ml21 with an RSD of 1.7% at the 10 ng ml21 level 410 Ca Fluorite XRF;–;S Sample 1.2 g was fused with a mixture of LiBO2±Li2B4O7, NaNO3 and KBr at 900 �C and 950 �C.For Ca calibration graphs were linear from 38±50%, with RSDs of 0.077% at the 44.8% level 411 Eu Sm±Eu±Gd concentrates AE;F;L The dual wavelength method plus La was used to eliminate spectral and chemical interferences using an air±acetylene Øame 412 F Fluorite XRF;–;S As for Ca. For F, calibration graphs were linear 35±48%, with RSDs of 0.26% at the 41.7% level 411 Gd Sm±Eu±Gd concentrates AE;F;L As for Eu 412 Si Fluorite XRF;–;S As for Ca.For Si, calibration graphs were linear 0.87±23.2%, with RSDs of 0.29% at the 10.9% level 411 Si Aluminium oxide AA;ETV;L 0.2 g of sample was mixed with ammonium Øuoride prior to decomposition with HCl. Si was determined by GFAAS with recoveries of 95.3± 105%. With Na concentration w6 mg ml21 deuterium background correction was needed 413 Sm Sm±Eu±Gd concentrates AE;F;L As for Eu 412 Various Bauxite AE;ICP;L 2.5 g of samples was treated with a series of HCl±HNO3±HClO4 solutions before dissolving Ænal residue in 2% HNO3.REEs were determined between 2.5±80 mg g21. LODs of 1±12 ng g21 with RSDs of 0.4±1.5% were obtained 414 Various (14) Erbium oxide MS;ICP;L Using matrix matching and 162Er as internal standard, interferences from other Er, Ho and Tm isotopes were negated. LODs of 7 mg l21 with recoveries of 95±100% at RSDs of 4.3±10% were obtained 415 Various Uranium oxide MS;SS;S A spark source method was employed to identify interference free isotope of REEs.Effects of Nd carbide and oxide formation were investigated 416 Various (14) Thulium oxide MS;ICP;L Sample was dissolved in 50% HNO3. Using standard additions recoveries for 14 REEs were 92±106% with RSDs of 1.3±1.6% 417 Various Eu2O3 and Yb2O3 MS;ICP;L Matrix effects were studied with respect to different internal standards for REE determinations. Ga, In, I, Cs and Tl were found to be suitable 418 Various Y2O3 AE;ICP;L Sample was dissolved using HCl and H2O2.REEs were separated on a silica gel column containing di-2-ethylhexylphosphoric acid. LODs were 3 mg g21 with RSDs of 0.2% 419 Various (14) Geological materials AE;ICP;L Ba was separated from the REEs in the samples using a Dowex 50 WX8 cation resin and then added subsquently as an internal standard 420 Various (14) Y2O3 MS;SS;S 20 REEs and other element were determined by an isotope dilution± internal standard method. RSDs of 8.4±16.2% were obtained 421 Various Lutetium oxide MS;ICP;L Cs was used as an internal standard to compensate for matrix suppression and drift.LODs of 0.006±0.035 mg l21 for REEs with recoveries of 84±112% and RSDs of 1.2±8.3% were obtained 422 Various (13) Pr6O11 MS;ICP;L Instrumental parameters such as rf power and carrier gas Øow rate were optimized for REE analysis. Interferences due to La and Ce were investigated 423 Various (14) Tm2O3, Yb2O3, Lu2O3 AE;–;L 2-Ethylhexonate-2-ethylhexyl phosphonate extraction chromatography was used to separate 14 REEs from ultra-pure oxides.Recoveries were between 72±128% with RSDs of 5.1±23.2% 424 Various (13) Samarium oxide MS;SS;S Sample was dissolved in HCl. Sm was separated on a P507 column and REEs preconcentrated onto activated charcoal pellets. The charcoal was mixed with Al2O3 and packed in a T-type electrode for spark analysis. RSDs were v23% 425 Various (14) Cerium oxide MS;ICP;L Ce matrix was separated form REEs by solvent extraction using 2-ethylhexylhydrogen- 2-ethylhexylphosphate.Recoveries were 94±102% with RSDs of 0.7±2.7% and LODs between 0.026±0.003 ng ml21 in solution 426 Various (11) Gadolinium oxide MS;ICP;L Sample was dissolved in 1% HNO3 and 205Tl was used as the internal standard.Recoveries for REEs were 94.1±117% with RSDs of 2.1± 8.1% 427 Various (27) Ytterbium oxide MS;ICP;L 50 mg was dissolved in 1 ml HNO3 (1 : 1). REEs and other analytes were determined by ICP-MS.LODs were 0.01±0.14 ng ml21 with recoveries of 88±104% 428 Various CeO2 AE;ICP;L 2 g was dissolved in HNO3±HF, evaporated, redissolved in H2O, passed through an ion-exchange column and REEs were eluted with 0.1 M KBrO3±HNO3. The eluent was evaporated and redissolved in HCl before analysis 429 Various (7) Eu2O3 MS;ICP;L Eu matrix effects could be eliminated with Rh internal standardization for Cr, Mn, Co, Ni, Cu, Cd and Pb determination. LODs of 0.12± 2.28 mg l21 with recoveries of 88.6±108.3% were obtained 430 1960 J.Anal. At. Spectrom., 1999, 14, 1937±1969reliant on the relative sensitivity coefÆcient which, in turn, can only be determined with the use of certiÆed standard reference materials or with the reliable determination of the trace elements in the sample. According to the authors, by using coefÆcients of 3 for B and Zn, respectively, for the determination of these elements in Bridgman GaAs single crystals results were obtained that compared favourably with charged particle activation analysis.However, analysis of Zn by INAA and AES measurements gave different coefÆcient values of 5 and 1, respectively. This demonstrates the care that must be taken when using techniques such as SSMS for this type of analysis. An ion-exchange methodology for the determination of trace elements in high-purity Ga, As, As oxides and mixtures of Ga and As has been reported.171 The analytes pre-concentrated by dissolving 0.5±2 g of the matrix in acid or alkali followed by separation on Dowex 1X8 (50±100 mesh) or Chelex 100 (50± 100 mesh).The desorbed elements were quantiÆed by ETAAS, FAAS, FAES, NAA and ICP-AES. The separation strategy for each matrix is detailed. The overall precision was 2±10% with recoveries of w95%. The analysis of materials and chemicals used in the semiconductor industry for trace contaminants continued to produce publications. The analysis of semiconductor-grade water by ICP-MS following a preconcentration step by boiling with mannitol has been described.172 A mixture of 50±750 g water sample and 20 ml of 10mgml21 mannitol was carefully evaporated to dryness at 85±90 �C.The mannitol proved to be very effective at preventing the loss of several elements such as Ti, Ge, Sn and Sb. The residue was dissolved in 3% HNO3 and the solution made up to 5 ml with the same solvent. The solution was analysed for 28 trace elements using cool and normal plasma conditions.Detection limits were 0.04± 16 pg ml21. Recoveries at the 200 fg g21 level were 80±120%. The method was also applied to ultra-pure electronic grade H2O2. In this case 20 ml of HCl were added to prevent explosive decomposition. Much effort is still being expended on the determination of impurities in silicon wafers. The surface and tomographic distribution of carbon in photonic-grade silicon using laserinduced breakdown spectrometry has been published.173 Light at 337.1 nm from a pulsed N laser was focused on an anisotropically etched (with dilute NaOH) Si wafer mounted on a computer-controlled stage that could be moved by a minimum of 10 mm in orthogonal directions.The plasma emission was focused by a 5.5 cm focal length quartz lens with detection using a 2D CCD detector. The intensities of the C I 589.1 and Si II 634.7 nm lines were monitored. Laser shots were Æred at 700 positions (3.062.1 mm) and the 2D distributions of C at the surface and at depths of 0.8 and 1.6 mm were derived from the emission distribution.The authors claim lateral and depth resolutions of 70 and 0.16 mm, respectively. Better lateral resolution could be obtained with improved focusing optics and more homogeneous laser beams. A quantitative method of metal impurities depth proÆling for gettering evaluation in silicon wafers has been developed.174 Three different methodologies of sample preparation were used: drop etching (DE) for surface oxide etching, drop sandwich etching (DSE) for near surface Si bulk etching and bulk decomposition (BD) for total Si bulk dissolution.By adopting this concept the authors were able to determine the redistribution of Fe in p- and n-type Si wafers. No loss of Fe by evaporation was observed. The method was applied to gettering evaluation of metal impurities in internal gettering, external gettering p/pz epi and SIMOX wafers. 3.3 Glasses A variety of techniques were applied for process control, including X-ray Øuorescence, ICP-MS, LA-ICP-MS and laser induced breakdown spectroscopy (LIBS).A new concept in XRF instrumentation for process control in the glass works was described in terms of operational use, calibration, sample preparation and handling. This instrument combined energy and wavelength dispersion into a single multi-dispersive system.175 A similar description of XRF, as applied to process control in the hollow glassware industry, included details of automated sample preparation and a discussion of calibrants. 176 The use of synchrotron X-ray micro-beam Øuorescence was applied as an NDA technique for the examination of insoluble gas species in inclusions in glasses.177 The complementary techniques of LA-ICP-MS and SEM-EDAX were applied to the macro- and micro-chemical analysis of vitriÆed domestic wastes.178 The LA system consisted of a quadrupled Nd:YAG laser with a pulse frequency of 1±20 Hz and maximum pulse energy of 4 mJ in the fully Q-switched mode. This was applied to the determination of 30 major, minor and trace analytes and, for the majority of elements, an Table 3 Summary of analyses of advanced materials (continued) Element Matrix Technique; atomization; presentation* Sample treatment/comments Ref.Various Silicates MS;ICP;L Signal suppression of 88Sr, 140Ce and 238U in rock matrices were reduced by high power operation (1.7 kW). Minimal dilution of samples is recommended with FIA offering reduced sample uptake 431 Y Rare earth concentrates AE;F;L The dual wavelength method (613.2 nm as the analytical and 612.9 nm as the reference wavelength) was used.LODs of 0.06 mg ml21 432 CATALYSTS– As Reforming catalyst AAS;HG;– m±wave digestion with HCl, redox conditioned to z3 with KI±ascorbic acid. QuantiÆcation via `standard addition and sequential dilution' method. LOD~0.2 mg g21 433 Li Dehydrogenation catalyst FAAS Sample digested with aqua regia in pressure PTFE vessel at 180 �C for 4 h.Air±acetylene Øame 434 PGE Automotive catalysts ICP;AES;L The catalysts were taken into solution via a Carius tube procedure 435 PGE Used automotive catalysts ICP;AES;L m±wave digestion with HNO3±HCl±H2O2 reagent in quartz digestion vessels 436 PGE Catalyst FAAS Sulfuric acid±aqua regia dissolution. La added 437 PGE Automotive catalysts LIBS Catalyst monoliths sectioned 438 V Titania supported silica catalysts LIBS Doubled Nd :YAG, LOD~38 mg g21 439 *Hy indicates hydride and S, L, G and Sl signify solid, liquid, gaseous or slurry sample introduction, respectively.Other abbreviations are listed elsewhere. J. Anal. At. Spectrom., 1999, 14, 1937±1969 1961accuracy of °20%, precision of RSD~10±20% and detection limits of about 100 ng g21 were reported. Secondary neutral mass spectrometry, in conjunction with AFM, was used to characterize sol±gel coatings (Li, Ba disilicates) on silica glass substrates.179 Detailed information on crystallinity, composition and phases was obtained and allowed the identiÆcation of residues from the processing of the substrate (Al2O3 grinding material).However, the most interesting process control reports involved LIBS as applied to in-situ/on-line analysis of glass and glass melts during the vitriÆcation of Øy and bottom ashes.180,181 A Q-switched Nd: YAG, operating at the fundamental wavelength, was focused through a pierced mirror onto the surface of the melt.The resultant plasma was imaged via the mirror onto a Æbre optic bundle and thence onto the entrance slit of a spectrograph equipped with an intensiÆed OMA. A multivariate calibration model was utilized (PLS) and a normalization procedure was developed based upon Saha± Boltzmann equilibrium relationships. Highly linear calibrations, based upon more than twenty different glass samples, were obtained and good agreement between the proposed and reference methods were achieved.Forensic analysis of glass fragments continues to be of interest and a combination of techniques were applied, e.g., m-XRF,182,183 ICP-MS184 and LA-ICP-MS.185 The use of statistical tools such as ANOVA184 and sophisticated chemometric procedures,185 e.g., cluster analysis, principal component analysis and linear discriminant analysis, have the potential to improve the resolution and reliability of the forensic identiÆcation of glass fragments.The use of SIMS, EPMXA and m-XRF, in conjunction with atomic force and scanning electron microscopy, provide powerful tools for the analysid investigation of archaeological glasses. Applications include identiÆcation of manufacturing centres,186,187 the Ærst appearance of organized industries within the Celtic civilization188 and the characterization of surface layers as an aid in the restoration and preservation of stained glass.189 3.4 Ceramics and refractories Work continues to be published on the problems of determining rare earth elements in their oxide matrices.A summary of such methods is provided in Table 3. Although commercial instruments now number in the hundreds, high resolution ICP-MS applications have been rather disappointing in their number this year. One application where the actual resolving power of high resolution instruments is utilized rather than their greater sensitivity has been the analysis of trace impurities in aluminium oxide.190 Sample dissolution was achieved using sulfuric acid and PTFE pressure vessels (16 h at 280 �C).Samples were diluted to a H2SO4 concentration of 0.18% and 25 trace elements determined using a resolution of R~5000. However, matrix effects still had to be overcome by the use of standard additions. Detection limits were v0.1 mg g21 for most elements. Other high resolution applications include the determination of ultra-trace metals in silicon wafers (v108 atoms m22).191 As with last year's review, researchers are continuing to search for methods that by-pass the traditional methods of sample preparation for refractory types of materials.A solid sampling, transversely heated graphite furnace AAS system for the analysis of high purity tantalum powders192 and aluminium oxide193 has been reported. Samples (0.1±60 mg, particle size v600 mg) are weighed by difference into a special pyrolytically coated graphite platform (Analytik, Jena, Germany).Problems caused by high background absorption as the platform aged were counteracted by re-coating the platform every 5±6 cycles. Calibration was achieved by aqueous standards with detection limits ranging from 0.25 ng g21 for Mg to 12 ng g21 for Ni in aluminium oxide and 0.02 ng g21 for Zn to 4 ng g21 for Fe in tantalum powders. The authors claim that this kind of performance gives improvements in detection limits of 64 (Fe) to 6250 (Mn) over liquid sampling ETAAS.The same workers have also developed a slurry sampling methodology for the analysis of ceramic powders194 and an ICP-AES method coupled to a novel tungsten coil vaporizer in a quartz chamber.195 A further reÆnement includes the use of a semiconductor diode laser, along with the previously mentioned tungsten coil atomizer.196 Detection limits of 0.02 mg g21 for Al in TiO2 using slurry sampling were obtained. Fluorination-assisted slurry sampling ETV-ICP-AES has been applied to the analysis of silicon nitride197,198 and silicon dioxide199 powders as well as using ETAAS detection.200 For all methods Øuorination was achieved by addition of a 60% m/v PTFE emulsion (viscosity 761023±1561023 Pa s) as a matrix modiÆer.Calibration in all instances was achieved with aqueous standards. Detection limits ranged from 0.11 mg g21 for Al in silicon nitride by ETV-ICP-AES to 18.8 ng g21 for Co in SiO2 powder by ETAAS. Several articles caught the eye this year concerning the depth proÆle analysis of various materials.A new method of depth proÆling has been applied to 161 cm2 sections of Coimpregnated Si wafer after oxidation and etching.201 The oxidation was performed using an oxygen plasma, resulting in a sublayer of SiO2 the thickness of which (3±10 nm) was dependent on the Co concentration. Etching was achieved using 4% HF. The mass of Si within the sublayer was determined by differential weighing. Solutions loaded with the oxide sublayer were dried by evaporation onto carriers with Co and Se (internal standard) being determined by total reØective XRF using an energy dispersive Si(Li) detector.The procedure is repeated up to 622, enabling a depth proÆle for Co to be constructed. The detection limit was 561018 Co atoms m23 with a depth resolution of 3 nm. Other interesting reports include the depth proÆling of thin TiSix Ælms on silicon carbide by SNMS202 and of Na in SiOx Ælms by chemical etching and SIMS.203 3.5 Catalysts The determination of platinum group elements (PGE) in automotive catalysts remains the main theme of this year's review.It has been suggested that the main anthropogenic input of PGE to the environment is from automotive catalysts. Automotive exhaust gases were sampled via a nitric acid bubbler. The trap contents were Æltered through a 0.45 mm Ælter to separate particulate and soluble PGE. After mineralization of the particulates, the PGE content of the two fractions was determined by quadrupole or sector Æeld ICPMS. 204,205 Initial results indicated that PGE were released at a ng km21 rate and that 90% of that release was as retained particulates. The application of secondary ionization mass spectrometry for surface characterization of catalysts continues to be an interesting Æeld of study. The surface modiÆcation of fresh, deactivated and reactivated borosilicate catalysts was studied by SIMS and XPS.206 Clear differences in the local chemistry of the pore structure were observed.A pore blocking mechanism due to the build up of nitrogenous species was detected. Changes in SiOz: SiOHz ratios in the topmost atomic layers during deactivation were shown to be reversed upon reactivation. Similarly, SIMS was used to characterize heterogeneous catalysts. The phase composition, and variation in that composition, was determined during catalyst use.207 References 1 J.M. Vadillo, C. C. Garcia, S. Palanco and J.J. Laserna, J. Anal. At. Spectrom., 1998, 13(8), 793. 1962 J. Anal. At. Spectrom., 1999, 14, 1937±19692 M. Sabsabi, L. St-Onge and P. Cielo, (Ind. Materials Inst., Natl. Res. Council Canada, Boucherville, PQ, Canada J4B 6Y4). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 3 R. J. H. Su, G. C. Allen and P. J. Heard, J. 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Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 40 M. M. Silva, M. G. T. Vale and E. B. Caramao, (Inst. Quim., Univ. Federal Rio Grande do Sul, 91501-970 Porto Alegre, rs, Brazil). Presented at 5th Rio Symposium on Atomic Spectrometry, Cancun, Mexico, October 4±10, 1998. 41 R. Heimburger, D. Davenet, T. Faller, D. Passe, E. Zimpfer and M. J. F. Leroy, J. Phys. IV, 1998, 8 (PR5, Rayons X et Matiere), Pr5/343. 42 D. J. Connolly, R. W. Dye, N. J. Mravich, C. C. Stauffer and B. A. Stuchell, U.S. US 5,818,899 (Cl. 375±45; G01N23/223), 6 October 1998, Appl. 832,425, 2 April 1997; 7 pp. 43 X. B. Feng and Y. T. Hong, Fenxi Ceshi Xuebao, 1998, 17(2), 41. 44 M. Bettinelli, S. Spezia and S. Roberti, At. Spectrosc., 1999, 20(1), 13. 45 R. Richaud, H. Lashas, A.-G. Collot, A. G. Mannerings, A. A. Herod, D. R. Dugwell and R. Kandiyoti, Fuel, 1998, 77(5), 359. 46 Characterization of sulfur in coal and coal products by standard and non-standard methods, Eur. Comm., [Rep.] EUR, EUR 17980, 1998, 1±3, 5±27, 29±33, 35±53, 55, 57±59, 63. 47 K. E. Levine, J. D. Batchelor, C. B. Rhoades Jr. and B. T. Jones, J. Anal. At. Spectrom., 1999, 14(1), 49. 48 M. Bettinelli, S. Spezia, G. Quattroni and A. Giove, Ann. Chim. (Rome), 1998, 88(3±4), 269. 49 H. Lachas, R. Richaud, K. E. Jarvis, A. A. Herod, D. R. Dugwell and R. Kandiyoti, Analyst (Cambridge, U.K.), 1999, 124(2), 177. 50 P. Daucik, Z. Zidek and P. Kalab, Chem. Pap., 1998, 52(5), 667. 51 T. Wakisaka, N. Morita, T. Hirabayashi and T. Nakahara, Bunseki Kagaku, 1998, 47(3), 157. 52 D. L. Langer and J. A. Holcombe, (Dept. Chem. and Biochem., Univ. Texas, Austin, TX 78712, USA). Presented at 5th Rio Symposium on Atomic Spectrometry, Cancun, Mexico, October 4±10, 1998. 53 M. Moder and B. Budic, (Lab. Petrol, PETROL d.d., 1260 Ljubljana, Slovenia). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 54 S. Shuttleworth, (Dept. Earth and Planetary Sci., Washington Univ., St. Louis, MO 63130, USA).Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 55 F. G. Smith, (CETAC Technologies, Omaha, NE, USA). Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 56 G.-C. Wang, G.-H. Zhu, L. Peng and Q.-H. Xu, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 31. 57 J. Zieba-Palus, Forensic Sci. Int., 1998, 91(3), 171. 58 K. M. Shi and C. Z. Da, Fenxi Shiyanshi, 1997, 16(3), 60. 59 G. Coleman, F. D. Bulman, G.R. Dulude and R. L. Stux, (Thermo Jarrell Ash Corp., Franklin, MA, USA). Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 60 C. Rivera and D. Shrader, (Varian Associates ± Optical Spectrosc. Instruments, Wood Dale, IL, USA). Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 61 I. M. Goncalves, M. Murillo and A. M. Gonzalez, Talanta, 1998, 47, 1033. 62 M. Seelig, N. H. Bings and J. A. C. Broekaert, Fresenius' J. Anal. Chem., 1998, 360(2), 161. 63 H. Dillen and V. Tusset, (OCAS N.V., 9060 Gent, Belgium). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 64 K. Krengel-Rothensee, U. Richter and P. Heitland, J. Anal. At. Spectrom., 1999, 14(4), 699. 65 X. Y. Du, C. M. Guan, Z. C. Shi and X. Z. Li, Fenxi Shiyanshi, 1998, 17(2), 84. 66 H. Chassaigne and R. Lobinski, Anal. Chim. Acta, 1998, 359(3), 227. 67 S. L. Deng and X. F. Li, Fenxi Huaxue, 1998, 26(2), 246. 68 K. Molt and R.Schramm, X-Ray Spectrom., 1999, 28(1), 59. 69 K. H. Angeyo, J. P. Patel, J. M. Mangala and D. G. S. Narayana, X-Ray Spectrom., 1998, 27(3), 205. 70 F.-K. Gao, S.-W. Zhang, X.-H. Yang, Z.-H. Cui, X.-H. Miao and G.-H. Gao, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 50. 71 E.-S. Ong and Y.-L. Yong, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 7. J. Anal. At. Spectrom., 1999, 14, 1937±1969 196372 B. Li, D.-H. Sun, L. Zhao and X.-R. Wang, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 11. 73 X.-H. Wu, D.-H. Sun, L. Zhao and X.-R. Wang, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 12. 74 D.-Q. Zhang, Z.-M. Ni and H.-W. Sun, Spectrochim. Acta, Part B, 1998, 53, 1049. 75 G. Leblanc, B. Haire and L. Jassie, (CEM Corp., Matthews, NC 28106-0200, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 76 M. M. Daniel, J. D. Batchelor, C. B. Rhoades Jr. and B. T. Jones, At. Spectrosc., 1998, 19(6), 198. 77 D.V. Vukomanovic, J. A. Stone, G. W. van Loon, K. Nakatsu and D. E. Zoutman, Spectrochim. Acta, Part B, 1998, 53, 893. 78 D. A. Barnett and G. Horlick, (Dept. Chem., Univ. Alberta, Edmonton, AB, Canada T6G 2G2). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 79 N. Shimizu, Y. Inoue, S. Daishima, K. Yamaguchi, K. Yoshida, K. Kuroda and G. Endo, (Yokogawa Anal. Systems Inc., Tokyo, Japan). Presented at 46th ASMS Conference on Mass Spectrometry, Orlando, FL, USA, 31 May±5 June, 1998. 80 J.Vogl and K. G. Heumann, Anal. Chem., 1998, 70(10), 2038. 81 E. Luong and R. Houk, (Dept. Chem., Iowa State Univ., Ames, IA 50011, USA). Presented at 46th ASMS Conference on Mass Spectrometry, Orlando, FL, USA, 31 May±5 June, 1998. 82 A. S. Al-Ammar, R. K. Gupta and R. M. Barnes, J. Anal. At. Spectrom., 1999, 14(5), 793. 83 S.-Q. Cao, H.-T. Chen and X.-J. Zeng, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 59. 84 M. G. A. Korn and E. de Oliveira, Spectrosc. Lett., 1998, 31(4), 699. 85 A. R. K. Dapaah and A. Ayame, Anal. Sci., 1997, 13(Supplement), 405. 86 A. R. K. Dapaah and A. Ayame, Anal. Chim. Acta, 1998, 360, (1±3), 43. 87 D. Atanasova, V. Stefanova and E. Russeva, Talanta, 1998, 45, 857. 88 G. H. Tao and Z. L. Fang, Fresenius' J. Anal. Chem., 1998, 360(2), 156. 89 J. Snell, J. Qian, M. Johansson, K. Smit and W. Frech, Analyst (Cambridge, U.K.), 1998, 123(5), 905. 90 R. M. Barnes, A.A. Al-Ammar and R. K. Gupta, (Dept. Chem. Lederle Graduate Res. Center Tower, Univ. Massachusetts, Amherst, MA 01003-4510, USA). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 91 A. A. Al-Ammar, R. K. Gupta and R. M. Barnes, J. Anal. At. Spectrom., 1999, 14(5), 801. 92 P. Krause and R. C. Hutton, (CETAC Technologies Inc., Crewe, Cheshire, UK CW1 1YX). Presented at Ninth Biennial National Atomic Spectroscopy Symposium, Bath, UK, July 8±10, 1998. 93 P.Krause and R. C. Hutton, (CETAC Technologies Ltd., Crewe, Cheshire, UK). Presented at 6th International Conference on Plasma Source Mass Spectrometry, Durham, England, September 13±18, 1998. 94 B. A. Buchholz, A. Arjomand, S. R. Dueker, P. D. Schneider, A. J. Clifford and J. S. Vogel, Anal. Biochem., 1999, 269(2), 348. 95 J. S. Becker, W. Kerl and H.-J. Dietze, Anal. Chim. Acta, 1999, 387(2), 145. 96 Y. Abdelnour, S. Skujins and A. Stroh, (Varian GmbH, 64289 Darmstadt, Germany).Presented at 6th International Conference on Plasma Source Mass Spectrometry, Durham, England, September 13±18, 1998. 97 W. Schron, A. Detcheva, B. Dressler and K. Danzer, Fresenius' J. Anal. Chem., 1998, 361(2), 106. 98 E. Bulska and W. Jedral, At. Spectrosc., 1997, 18(6), 202. 99 C. M. Davidson, A. L. Duncan, D. Littlejohn, A. M. Ure and L. M. Garden, Anal. Chim. Acta, 1998, 363, 45. 100 S. Ahsan, S. Kaneco, K. Ohta, T. Mizuno, T. Suzuki, M.Miyada and Y. Taniguchi, Anal. Chim. Acta, 1998, 362, 279. 101 Y. Zhou, Lihua Jianyan, Huaxue Fence, 1998, 34(11), 518. 102 J. Xiao, H. Z. Xiong and H. L. Liu, Fenxi Shiyanshi, 1997, 16(4), 64. 103 X.-F. Wang, Y.-C. Hao, L.-L. Zhou, H.-X. Bao and J.-Y. Wang, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 72. 104 S.-Y. Chen, J.-C. Zou and X.-J. Guan, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 63. 105 R. K. Tepe, T. Jacksier and R. M. Barnes, J. Anal. At. Spectrom., 1998, 13(9), 989. 106 T. Nakahara and T. Nishida, Spectrochim. Acta, Part B, 1998, 53, 1209. 107 P. Heitland, U. Richter and K. Krengel-Rothensee, GIT Labor- Fachz., 1998, 42(8), 779. 108 Y. Hu, F. Vanhaecke, L. Moens, R. Dams and I. Geuens, J. Anal. At. Spectrom., 1999, 14(4), 589. 109 N. Nonose and M. Kubota, J. Anal. At. Spectrom., 1998, 13(2), 151. 110 M. Pantsar-Kallio and P. K. G. Manninen, Anal. Chim. Acta, 1998, 360, 161. 111 C. S. J. Briche, A. Held and P. D. P. Taylor, (Inst. Reference Materials and Measurements, Geel, Belgium). Presented at 46th ASMS Conference on Mass Spectrometry, Orlando, FL, USA, 31 May±5 June, 1998. 112 A. P. de S. Jorge, J. Enzweiler, E. K. Shibuya, J. E. S. Sarkis and A. M. G. Figueiredo, Geostand. Newsl., 1998, 22(1), 47. 113 G. A. Bickel, F. C. Sopchyshyn, G. A. McRae, Z. H. Walker and L. W. Green, Nucl. Instrum. Methods Phys. Res., Sect. B, 1998, B140(1±2), 217. 114 F. Vanhaecke, J. Diemer, K. G. Heumann, L. Moens and R. Dams, Fresenius' J.Anal. Chem., 1998, 362(7±8), 553. 115 H. M. Kingston, D. Huo, Y. Lu and S. Chalk, Spectrochim. Acta, Part B, 1998, 53(2), 299. 116 M. Ohnishi-Kameyama and T. Nagata, Anal. Chem., 1998, 70(9), 1916. 117 N. Kallithrakas-Kontos and R. Moshohoritou, X-Ray Spectrom., 1998, 27(3), 173. 118 S. Piorek, E. Piorek and G. Johnson, Characterization of liquid hazardous waste with a Æeld portable energy-dispersive X-ray analyzer, Air and Waste Management Assoc., Pittsburgh, PA, USA, 1997, 842±847. 119 J.S. Becker, H.-J. Dietze and A. Montaser, (Central Dept. Anal. Chem., Res. Centre Juelich, 52425 Juelich, Germany). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 120 J. Sabine-Becker and H.-J. Dietze, (Central Dept. Anal. Chem., Res. Centre Juelich, Juelich, Germany). Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 121 A. Lopez Molinero, R. Sanz Alberto Morales, P. Chamorro and J. R. Castillo, (Dept.Anal. Chem., Fac. Sci., Univ. Zaragoza, 50009 Zaragoza, Spain). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10± 15, 1999. 122 J. Sabine Becker, R. S. Soman, K. L. Sutton, J. A. Caruso and H.-J. Dietze, J. Anal. At. Spectrom., 1999, 14(6), 933. 123 J. M. Barrero Moreno, M. Betti and G. Nicolaou, J. Anal. At. Spectrom., 1999, 14(5), 875. 124 J. M. Barrero Moreno and M. Betti, (European Commission, Inst. Transuranium Elements, 76125 Karlsruhe, Germany).Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 125 F. Pointurier, R. Chiappini, P. Hemet, T. Thome and J. Samak, (CEA/DAM/DIF/DASE/RCE, 91680 Bruyeres-le-Chatel, France). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 126 T. Muto and T. Shimokawa, Tokyo-toritsu Aisotopu Sogo Kenkyusho Kenkyu Hokoku, 1997, 14, 79. 127 P. Becotte-Haigh, J.F. Tyson and E. Denoyer, J. Anal. At. Spectrom., 1998, 13(12), 1327. 128 H. Ramebaeck, Y. Albinsson, M. Skaalberg and U. B. Eklund, Fresenius' J. Anal. Chem., 1998, 362(4), 391. 129 H. Ramebaeck and M. Skalberg, J. Radioanal. Nucl. Chem., 1998, 235(1±2), 229. 130 E. J. Wyse, J. A. MacLellan, C. W. Lindenmeier, J. P. Bramson and D. W. Koppenaal, J. Radioanal. Nucl. Chem., 1998, 234(1±2), 165. 131 A. Amaral, P. Galle, C. Cossonnet, D. Franck, P. Pihet, M. Carrier and O.Stephan, J. Radioanal. Nucl. Chem., 1997, 226(1±2), 41. 132 E. Werner, P. Roth, I. Wendler, P. Schramel, H. Hellmann and U. Kratzel, J. Radioanal. Nucl. Chem., 1997, 226(1±2), 201. 133 A. Amaral, C. Cossonnet and P. Galle, Radiat. Prot. Dosim., 1998, 79(1±4, Intakes of Radionuclides), 137. 134 W. C. Inkret, D. W. Efurd, G. Miller, D. J. Rokop and T. M. Benjamin, Int. J. Mass Spectrom., 1998, 178(1±2), 113. 135 N. Erdmann, C. Gruning, N. Trautmann, A. Waldek, G. Huber, P. Kunz, M.Nunnemann and G. Passler, AIP Conf. Proc., 1998, 454(Resonance Ionization Spectroscopy), 279. 136 J. E. McAninch, A. A. Marchetti, B. A. Bergquist, N. J. Stoyer, G. J. Mimz, M. W. Caffee, R. C. Finkel, K. J. Moody, E. Sideras- 1964 J. Anal. At. Spectrom., 1999, 14, 1937±1969Haddad, B. A. Buchholz, B. K. Esser and I. D. Proctor, J. Radioanal. Nucl. Chem., 1998, 234(1±2), 125. 137 F. X. Martin, G.M. Raisbeck and F. Yiou, Mineral. Mag., 1998, 62A(FPt. 2), 953. 138 M. Nunnemann, N. Erdmann, H.-U.Hasse, G. Huber, J. V. Kratz, P. Kunz, A. Mansel, G. Passler, O. Stetzer, N. Trautmann and A. Waldek, J. Alloys Compd., 1998, 271(1±2), 45. 139 C. Gruning, N. Erdmann, G. Huber, P. Klopp, J. V. Kratz, P. Kunz, M. Nunnemann, G. Passler, O. Stetzer, A. Waldek and K. Wendt, AIP Conf. Proc., 1998, 454(Resonance Ionization Spectroscopy), 285. 140 C. Walker, J. Anal. At. Spectrom., 1999, 14(3), 447. 141 M. Mogensen, J. H. Pearce and C. T. Walker, J. Nucl. Mater., 1999, 264(1±2), 99. 142 K. D. S. Mudher, J. Indian Chem. Soc., 1997, 74(10), 753. 143 P. Trabuc, Ph. Llug and Ph. Bienvenu, J. Phys. IV, 1998, 8(PR5, Rayons X et Matiere), Pr5/351. 144 J. R. Schoonover and G. J. Havrilla, Appl. Spectrosc., 1999, 53(3), 257. 145 Y. Higashi, T. Maruo and Y. Homma, Surf. Interface Anal., 1997, 26(3), 220. 146 H. J. Mathieu, J. Surf. Anal., 1998, 4(1), 6. 147 R. Newman, Proc. SPIE-Int. Soc. Opt. Eng., 1998, 3315(ScientiÆc Detection of Fakery in Art), 31. 148 B. Wehling, P. Vandenabeele, L. Moens, R. Klockenkamper, A. von Bohlen, G. Van Hooydonk and M. de Reu, Mikrochim. Acta, 1999, 130(4), 253. 149 P. Vandenabeele, B. Wehling, L. Moens, B. Dekeyzer, B. Cardon, A. von Bohlen and R. Klockenkaemper, Analyst (Cambridge, U.K.), 1999, 124(2), 169. 150 G. Weber, J. M. Delbrouck, D. Strivay, F. Kerff and L. Martinot, Nucl. Instrum. Methods Phys. Res., Sect. A, 1998, B139(1±4), 196. 151 R. Fonseca, (General Electric Corp. Res. and Development, Niskayuna, NY, USA).Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 152 A. J. G. Mank, P. Rommers and A. Dobney, (Philips CFT, 5656 AA Eindhoven, Netherlands). Presented at 6th International Conference on Plasma Source Mass Spectrometry, Durham, England, September 13±18, 1998. 153 P. J. Rommers and A. J. G. Mank, (A.J.G. Mank Philips CFT, 5656AA Eindhoven, Netherlands). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 154 H. J. Hakkanen and J. E. I. Korpi-Tommola, Anal. Chem., 1998, 70(22), 4724. 155 R. E. Wolf, C. Thomas and A. Bohlke, Appl. Surf. Sci., 1998, 127, 299. 156 J.-L. Todoli and J.-M. Mermet, Spectrochim. Acta, Part B, 1998, 53, 1645. 157 J. Batey and S. Nelms, (VG Elemental, Winsford, Cheshire, UK CW7 3BX). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 158 T. E. Gibeau and R. K. Marcus, J. Anal. At. Spectrom., 1998, 13(12), 1303. 159 R. Maibusch, H.-M. Kuss, A. G. Coedo, T. Dorado and I. Padilla, J. Anal. At. Spectrom., 1999, 14(8), 1155. 160 G. A. Giacomozzi, R. R. U. Querioz, I. G. Souza and J. A. G. Neto, J. Autom. Methods Manage. Chem., 1999, 21(1), 17. 161 M. Verstraete, F. Vanhaecke, L. Moens, R. Dams and A. V. Alphen, (Lab. Anal. Chem., Inst. Nucl. Sci., Ghent Univ., 9000 Ghent, Belgium). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 162 M. A. Belarra, I. Belategui, I. Lavilla, J. M. Anzano and J. R. Castillo, Talanta, 1998, 46(6), 1265. 163 F. Vanhaecke, M. Verstraete, L. Moens, R. Dams and M. Nekkers, Anal. Commun., 1999, 36(3), 89. 164 A. van Alphen, (Dept. RGA, Section Atomic Spectrom., Akzo Nobel Central Res., 6800 SB Arnhem, Netherlands). Presented at 6th International Conference on Plasma Source Mass Spectrometry, Durham, England, September 13±18, 1998. 165 Y. Hu, F. Vanhaecke, L. Moens and R.Dams, (Lab. Anal. Chem., Inst. Nucl. Sci., Ghent Univ., 9000 Ghent, Belgium). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 166 M. L. Hartenstein, P. Chapon, T. E. Gibeau and R. K. Marcus, (Dept. Chem., Howard L. Hunter Lab., Clemson Univ., Clemson, SC 29634-1905, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 167 R. K. Marcus, M. A. Jones and T. E. Gibeau, (Dept.Chem., Howard L. Hunter Lab., Clemson Univ., Clemson, SC 29634-1905, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 168 A. K. Bledzki and D. Kardasz, Polimery (Warsaw), 1998, 43(2), 79. 169 J. S. Becker, R. S. Soman, T. Becker, V. K. Panday and H.-J. Dietze, J. Anal. At. Spectrom., 1998, 13(9), 983. 170 B. Wiedemann, K. Bethke, K. G. Heumann and G. Raedlinger, PTB-Ber. ThEx-Phys.-Tech.-Bundesanst., 1997(PTB-ThEx-3), 115. 171 S. Kayasth, N. Raje, T. P. S. Asari and R. Parthasarathy, Anal. Chim. Acta, 1998, 370(1), 91. 172 K. Takeda, S. Watanabe, H. Naka, J. Okuzaki and T. Fujimoto, Anal. Chim. Acta, 1998, 377(1), 47. 173 D. Romero and J. J. Laserna, J. Anal. At. Spectrom., 1998, 13(6), 557. 174 M. B. Shabani, T. Yoshimi, S. Okuuchi and H. Abe, Diffus. Defect Data, Pt. B, 1997, 57, 81. 175 Ind. Ceram. Verriere, 1997, 932, 878 176 J. Buchmayer, LaborPraxis, 1998, 22(10), 48. 177 C. Romano, D.B. Dingwell and F. Lechtenberg, Phys. Chem. Glasses, 1998, 39(3), 181. 178 M. Motelica-Heino, P. Le Coustumer, J. H. Thomassin, A. Gauthier and O. F. X. Donard, Talanta, 1998, 46(3), 407. 179 R. Schmitz and G. H. Firschat, Glass Sci. Technol. (Frankfurt/ Main), 1998, 71(4), 92. 180 U. Panne, C. Haisch, M. Clara and R. Niessner, Spectrochim. Acta, Part B, 1998, 53, 1957. 181 U. Panne, M. Clara, C. Haisch and R. Niessner, Spectrochim. Acta, Part B, 1998, 53, 1969. 182 T.Goldmann, T. Hicks and P. Margot, Curr. Top. Forensic Sci., Proc. Meet. Int. Assoc. Forensic Sci. 14th 1996, 1997, 4, 74. 183 LaborPraxis, 1998, 22(7±8), 78. 184 D. C. Duckworth, C. K. Bayne, S. J. Morton, D. H. Smith, J. R. Almirall, R. D. Koons and K. G. Furton, (Oak Ridge Natl. Lab., Oak Ridge, TN, USA). Presented at 46th ASMS Conference on Mass Spectrometry, Orlando, FL, USA, 31 May±5 June, 1998. 185 S. Becker, A. Chadzelek and W. Stoecklein, (Bundeskriminalamt Forensic Sci.Inst., 11 65173 Wiesbaden, Germany). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 186 I. De Raedt, K. Janssens and J. Veeckman, J. Anal. At. Spectrom., 1999, 14(3), 493. 187 K. H. Janssens, I. Deraedt, O. Schalm and J. Veeckman, Mikrochim. Acta, Suppl., 1998, 15(Modern Developments and Applications in Microbeam Analysis), 253. 188 J. Braziewicz, M. Karwowski, M. Jaskola and M. Pajek, Adv. XRay Anal., 1997, 39, 857. 189 M.Schreiner, G. Woisetschlaeger, I. Schmitz and M. Wadsak, J. Anal. At. Spectrom., 1999, 14(3), 395. 190 K. Nakane, Y. Uwamino, H. Morikawa, A. Tsuge and T. Ishizuka, Anal. Chim. Acta, 1998, 369(1±2), 79. 191 M. Hamester, J. Wills and D. Wiederin, (Finnigan MAT GmbH, 28197 Bremen, Germany). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5± 10, 1998. 192 K.-C. Friese and V. Krivan, Spectrochim. Acta, Part B, 1998, 53, 1069. 193 M.Lucic and V. Krivan, J. Anal. At. Spectrom., 1998, 13(10), 1133. 194 M. Lucic and V. Krivan, Appl. Spectrosc., 1998, 52(5), 663. 195 M. Lucic and V. Krivan, Fresenius' J. Anal. Chem., 1999, 363(1), 64. 196 V. Krivan, P. Barth and C. Schnuerer-Patschan, Anal. Chem., 1998, 70(17), 3525. 197 P. Tianyou, J. Zucheng and Q. Yongchao, J. Anal. At. Spectrom., 1999, 14(7), 1049. 198 T.-Y. Peng, Z.-C. Jiang, B. Hu and Z.-H. Liao, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 57. 199 T.Y. Peng and Z. C. Jiang, Fresenius' J. Anal. Chem., 1998, 360(1), 43. 200 F. Wang, Z. Jiang and T. Peng, J. Anal. At. Spectrom., 1999, 14(6), 963. 201 R. Klockenkaemper and A. von Bohlen, Anal. Commun., 1999, 36(2), 27. 202 R. Getto, J. Freytag, M. Kopnarski and H. Oechsner, Mater. Sci. J. Anal. At. Spectrom., 1999, 14, 1937±1969 1965Forum, 1998, 287(Trends and New Applications of Thin Films), 231. 203 R. Saito and M. Kudo, Jpn. J. Appl. Phys., Part 1, 1998, 37(2), 690. 204 M. A. Palacios, M. Gomez, M. Moldovan, G. Morrison, S. Rauch, C. McLeod, S. Caroli, P. Schramel, S. Lustig, J. Laserna, P. Lucena, J. C. Saenz, M. Luna and J. Santamaria, (Dept. Quim. Anal., Fac. Quim., Univ. Complutense, 28040 Madrid, Spain). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 205 M. Moldovan, M. Gomez and M. A. Palacios, (Dept. Quim. Anal., Fac. Quim., Univ. Complutense, 28040 Madrid, Spain). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 206 P. Albers, K. Seibold, T. Haas, G. Prescher and W. F. Holderich, J. Catal., 1998, 76(2), 561. 207 F. De Smet, M. Devillers, C. Poleunis and P. Bertrand, J. Chem. Soc., Faraday Trans., 1998, 94(7), 941. 208 C. Q. Tian, Lihua Jianyan, Huaxue Fence, 1998, 34(4), 175. 209 S.-I. Chang, H.-M. Liu and S.-J. J. Tsai, J. Anal. At. Spectrom., 1998, 13(10), 1123. 210 M. B. Oss Giacomelli, J. B. Borba da Silva and A.J. Curtius, Talanta, 1998, 47, 877. 211 M. Zhu and Z. M. Lu, Lihua Jianyan, Huaxue Fence, 1999, 35(1), 34. 212 M. C. Yebra-Biurrun, Lab. Rob. Autom., 1998, 10(5), 299. 213 M. W. Hinds, Spectrochim. Acta, Part B, 1998, 53, 1063. 214 M. M. Li, G. F. Wan and Y. F. Zhao, Lihua Jianyan, Huaxue Fence, 1999, 35(2), 57. 215 S. M. Hasany, A. A. Khan and H. Rehman, J. Radioanal. Nucl. Chem., 1998, 232(1±2), 195. 216 A. P. M. de Win, J. Anal. At. Spectrom., 1998, 13(4), 315. 217 Y.Danzaki, K. Takada and K. Wagatsuma, Fresenius' J. Anal. Chem., 1998, 362(4), 421. 218 S. Kozuka, Y. Yamada, M. Takenaka, M. Hayashi and H. Matsunaga, Anal. Sci., 1997, 13(6), 1017. 219 L. S. G. Teixeira, J. O. N. Reis, A. C. S. Costa, S. L. C. Ferreira, M. G. A. Korn and J. B. De Andrade, Talanta, 1998, 46(6), 1279. 220 S. Tokahoglu, S. Kartal and L. Elci, Mikrochim. Acta, 1997, 127(3±4), 281. 221 Z. W. Mao, J. Peng, X. Zhang and Z. C. Peng, Guangpuxue Yu Guangpu Fenxi, 1997, 17(6), 80. 222 G.Y. Yao, L. Q. Peng and W. B. Xie, Fenxi Shiyanshi, 1997, 16(3), 54. 223 H. Yamaguchi, S. Itoh, S. Igarashi, K. Naitoh and R. Hasegawa, Fresenius' J. Anal. Chem., 1998, 362(4), 395. 224 S. J. Kumar, N. N. Meeravali and J. Arunachalam, Anal. Chim. Acta, 1998, 371(2±3), 305. 225 E. S. Blinova and V. G. Miskar'yants, Zavod. Lab., Diagn. Mater., 1998, 64(9), 21. 226 X. F. Liu and Y. W. Wang, Fenxi Huaxue, 1998, 26(4), 474. 227 V. K. Karandashev, A. N. Turanov, H.-M.Kuss, I. Kumpmann, L. V. Zadnepruk and V. E. Baulin, Mikrochim. Acta, 1998, 130(1±2), 47. 228 I. Karadjova, L. Jordanova and S. Arpadjan, Mikrochim. Acta, 1997, 127(3±4), 225. 229 X. J. Feng and B. Fu, Anal. Chim. Acta, 1998, 371(1), 109. 230 N. F. Beizel, Zavod. Lab., Diagn. Mater., 1998, 64(12), 22. 231 K. Loebe and H. Lucht, GIT Labor-Fachz., 1998, 42(2), 105. 232 D. Grientschnig, H. Huber and R. Leitgeb, Spectrochim. Acta, Part B, 1998, 53B, 1601. 233 A. G. Coedo, M.T. Dorado, I. Padilla and F. J. Alguacil, J. Anal. At. Spectrom., 1998, 13(10), 1193. 234 S. Kozono, H. Sakamoto, R. Takashi and H. Haraguchi, Anal. Sci., 1998, 14(4), 757. 235 S. Liang and D. C. Tilotta, Anal. Chem., 1998, 70(21), 4487. 236 A. Shafawi, L. Ebdon, M. Foulkes, P. Stockwell and W. Corns, Analyst (Cambridge, U.K.), 1999, 124(2), 185. 237 T. Ohshima, H. Moriguchi, R. Shigemasa, S. Goto, M. Tsunotani and T. Kimura, Jpn. J. Appl. Phys., Part 1, 1999, 38(2B), 1161. 238 K. Komine and K. Tomoike, Idemitsu Giho, 1997, 40(6), 616. 239 F. McElroy, A. Mennito, E. Debrah and R. Thomas, Spectroscopy (Eugene, Oreg.), 1998, 13(2), 42. 240 R. N. Garavaglia, R. E. Rodriguez and D. A. Batistoni, Fresenius' J. Anal. Chem., 1998, 360(6), 683. 241 J. L. Hammond, Y.-I. Lee, C. O. Noble, J. N. Beck, C. E. ProfÆtt and J. Sneddon, Talanta, 1998, 47, 261. 242 J. Goschnick, C. Natzeck and M. Sommer, Appl. Surf. Sci., 1999, 144, 31. 243 S. Spezia and M. Bettinelli, (ENEL SpA, Piacenza, Italy).Presented at 6th International Conference on Plasma Source Mass Spectrometry, Durham, England, September 13±18, 1998. 244 X. X. Sun, Guangpuxue Yu Guangpu Fenxi, 1998, 18(6), 707. 245 S. Wangkarn and S. A. Pergantis, J. Anal. At. Spectrom., 1999, 14(4), 657. 246 J. T. Creed, X. Wei and C. A. Brockhoff, (Natl. Exposure Res. Lab., Microbiol. and Chem. Exposure Assessment Res. Div., US Environ. Protection Agency, Cincinnati, OH 45268, USA). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 247 J. E. de Souza Sarkis, M. da Silva Gomes, J. Bonetti Filho and C. Bonetti, (Inst. Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo CEP 05508-900, Brazil). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 248 S. Kozono, M. Yagi and R. Takashi, Anal. Chim. Acta, 1998, 368(3), 275. 249 J. Chirinos, A. Fernandez and J. Franquiz, J. Anal.At. Spectrom., 1998, 13(9), 995. 250 J. G. Zheng and Z. X. Zhang, Fenxi Ceshi Xuebao, 1998, 17(3), 58. 251 D. Colbert, K. S. Johnson and K. H. Coale, Anal. Chim. Acta, 1998, 377(2±3), 255. 252 M. E. M. da Piedade and M. N. Berberan-Santos, J. Chem. Educ., 1998, 75(8), 1013. 253 A. J. Schleisman, S. Anderson, B. Tillotson and D. Bollinger, (Air Liquide Electronics Chemicals Services, Inc., Dallas, TX 75243, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 254 S. Ishimitsu, I. Mishima, S. Tsuji and T. Shibata, Shokuhin Eiseigaku Zasshi, 1998, 39(5), 341. 255 B. Koschuh, M. Montes, J. F. Camuna, R. Pereiro and A. Sanz- Medel, Mikrochim. Acta, 1998, 129(3±4), 217. 256 F. Lepkojus, N. Watanabe, W. Buscher, K. Cammann and G. Bohm, J. Anal. At. Spectrom., 1999, 14(9), 1511. 257 P. Shaw, (VG Elemental, Winsford, Cheshire, UK CW7 3BX). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 258 S. T. Liu, P. Luo, T. Xie, T. C. Jiang, D. S. Mo and L. Zhang, Lihua Jianyan, Huaxue Fence, 1998, 34(11), 517. 259 J. Rodriguez, R. Pereiro and A. Sanz-Medel, J. Anal. At. Spectrom., 1998, 13(9), 911. 260 S. Leikin and D. Tsourides, (Spectro Analytical Instruments, Fitchburg, MA 01420, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 261 J. A. C. Broekaert, T. K. Starn, L.J. Wright and G. M. Hieftje, Spectrochim. Acta, Part B, 1998, 53, 1723. 262 A. V. Lopez Gomez and J. Martinez Calatayud, Analyst (Cambridge, U.K.), 1998, 123(10), 2103. 263 S. S. M. Hassan, A. B. Abbas and M. A. F. Elmosallamy, Mikrochim. Acta, 1998, 128(1±2), 69. 264 L. G. Chen, L. J. Zhang and Y. Liu, Lihua Jianyan, Huaxue Fence, 1997, 33(12), 559. 265 D. J. Figg, J. B. Cross and C. Brink, Appl. Surf. Sci., 1998, 127, (1±2), 287. 266 E. Tatar, V. G. Mihucz, A. Varga, G. Zarav and F.Fodor, Microchem. J., 1998, 58(3), 306. 267 Y. Yang and L. C. Chen, Lihua Jianyan, Huaxue Fence, 1998, 34(7), 326. 268 H. R. Ravindra, G. RadhaKrishna, V. VijayaLakshmi, B. Gopalan, S. Syamsundar, S. G. Kulkarni, S. B. Manohar and D. D. Sood, Determination of hafnium in organic stream samples by X-ray Øuorescence spectrometric technique using a selective crystal, NUCAR 95: Proc. Nucl. Radiochem. Symp. Bhabha Atomic Res. Center, Bombay, India, 1995, 368±369. 269 M. Patriarca, N.A. Kratochwil and P. J. Sadler, J. Anal. At. Spectrom., 1999, 14(4), 633. 270 K. L. Sutton, K. L. Ackley, J. A. Day and J. A. Caruso, (Dept. Chem., Univ. Cincinnati, Cincinnati, OH 45221-0172, USA). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 271 F. Yang and Y. K. Chau, Analyst (Cambridge, U.K.), 1999, 124(1), 71. 272 A. Rocha, A. Anderson, N. Miekeley, C. L. P. Da Silveira and M. C. M. Bezerra, Quim. Nova, 1998, 21(5), 584. 273 L. Qi and H. Lee, J. Anal. At. Spectrom., 1998, 13(10), 1203. 274 L. Q. Zhou, H. C. Cai and G. F. Yu, Lihua Jianyan, Huaxue Fence, 1998, 34(10), 462. 275 P. Luo and S. T. Liu, Lihua Jianyan, Huaxue Fence, 1998, 34(10), 469. 276 Q. Liang, Fenxi Ceshi Xuebao, 1998, 17(6), 66. 1966 J. Anal. At. Spectrom., 1999, 14, 1937±1969277 F. Laborda, J. Medrano, Y. Sanz and J. R. Castillo, (Anal. Spectrosc. and Sensors Group, Dept. Anal. Chem., Univ. Zaragoza, 50009 Zaragoza, Spain).Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 278 X. G. Liu, J. D. Fang and P. Wang, Guangpuxue Yu Guangpu Fenxi, 1997, 17(5), 90. 279 S. Z. Zhang and C. M. Wang, Guangpuxue Yu Guangpu Fenxi, 1997, 17(6), 53. 280 J. Y. Zhang, Lihua Jianyan, Huaxue Fence, 1998, 34(2), 71. 281 A. L. R. Sekaly, M. H. Back, C. L. Chakrabarti, D. C. Gregoire, J. Y. Lu and W. H. Schroeder, Spectrochim. Acta, Part B, 1998, 53, 837. 282 A. L. R. Sekaly, M. H. Back, C. L. Chakrabarti, D. C. Gregoire, J. Y. Lu and W. H. Schroeder, Spectrochim. Acta, Part B, 1998, 53, 847. 283 A. N. Smagunova, E. N. Korzhova and T. M. Velikova, J. Anal. Chem. (Transl. of Zh. Anal. Khim.), 1998, 53(7), 594. 284 N. Efe and H. Yilmaz, Spectrosc. Lett., 1998, 31(6), 1207. 285 R. Myors, R. J. Wells, S. V. Skopec, P. Crisp, R. Iavetz, Z. Skopec, A. Ekangaki and J. Robertson, Anal. Commun., 1998, 35(12), 403. 286 L. Yu, X.-Z. Sun, H.-Q.Fang, B.-Y. Lu and L.-W. Qiu, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 24. 287 P. Cheneviere, J. P. Laurent and M. Grall, (Groupement Recherches de Lacq, Elf±Elf atochem., 64170 Artix, France). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 288 C. Pickhardt, J. S. Becker, K. G. Heumann and H.-J. Dietze, (Central Dept. Anal. Chem., Res. Centre Juelich, 52425 Juelich, Germany). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 289 A. B. Anfone, M. L. Hartenstein and R. K. Marcus, (Dept. Chem., Clemson Univ., Clemson, SC 29634-1905, USA). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 290 P. Costamagna, D. Jacques and B. Morel, (COMURHEX, 26701 Pierrelatte, France). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 291 I. B. Brenner, M. Liezers, J.Godfrey, S. Nelms and J. Cantle, Spectrochim. Acta, Part B, 1999, 54, 991. 292 K. V. Thomas, J. Chromatogr., A, 1999, 833(1), 105. 293 L. Paama, H. Ronkkomaki and P. Peramaki, Talanta, 1997, 45(1), 35. 294 P. Luna, M. Tudino and O. Troccoli, (Lab. Anal. Trazas, INQUIMAE, Fac. Ciencias Exactas y Naturales, Univ. Buenos Aires, Buenos Aires, Argentina). Presented at 5th Rio Symposium on Atomic Spectrometry, Cancun, Mexico, October 4±10, 1998. 295 V. T. Demarin, A. D. Zorin, A.Yu. Vazhnev and L. V. Sklemina, Zavod. Lab., Diagn. Mater., 1998, 64(11), 23. 296 J. J. Konrad and R. A. Sinicki, U.S. US 5,723,339 (Cl. 436±73; G01N33/20), 3 March 1998, Appl. 632,231, 15 April 1996; 4 pp. 297 X. Yu, J. G. Chen, S. Q. Wang, Z. H. Liao and Z. C. Jiang, Fenxi Shiyanshi, 1998, 17(1), 57. 298 G. G. Glavin and R. M. Barnes, (Dept. Chem., Lederle Graduate Res. Center, Univ. Massachusetts, Amherst, MA 01003-43510, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 299 X. Chang, Z. Su, D. Yang, B. Gong, Q. Pu and S. Li, Anal. Chim. Acta, 1997, 354, 143. 300 B. Budic, Acta Chim. Slov., 1997, 44(3), 261. 301 J. Y. Neira, C. G. Bruhn, N. Reyes and H. Berndt, (Dept. Anal. Instrumental, Fac. Farm., Univ. Concepcion, Concepcion, Chile). Presented at 5th Rio Symposium on Atomic Spectrometry, Cancun, Mexico, October 4±10, 1998. 302 S. Ahsan, S. Kaneco, K. Ohta, T. Mizuno and Y. Taniguchi, Talanta, 1999, 48, 63. 303 M. E. Conti, Food Res. Int., 1997, 30(5), 343. 304 H.-J. Shi, X.-H. Wang and H.-S. Liu, Gaodeng Xuexiao Huaxue Xuebao, 1999, 20(5), 34. 305 M. Avila Rodriguez, J. A. Barron Zambrano, A. Alatorre Ordaz, R. Navarro Mendoza and T. I. Saucedo Medina, Talanta, 1998, 45(5), 875. 306 L. F. Bencs and O. Szakacs, Spectrochim. Acta, Part B, 1997, 52B(9±10), 1483. 307 O. Nygren and J. E. Wahlberg, Analyst (Cambridge, U.K.), 1998, 123(5), 935. 308 X. Jia, S. Hayakawa, K.Ugajin, N. Wakatsuki, E. Sugiyama, T. Takahashi, A. Ohnishi, Y. Gohshi and M. Wakatsuki, Koatsuryoku no Kagaku to Gijutsu, 1998, 7(Proceedings of International Conference ± AIRAPT-16 and HPCJ-38±on High Pressure Science and Technology, 1997), 998. 309 H. F. Yu, H. M. Li, S. S. Xu, L. L. Ma and K. S. Diao, Guangpuxue Yu Guangpu Fenxi, 1997, 17(6), 76. 310 Y. G. Dong and H. J. Shen, Guangpuxue Yu Guangpu Fenxi, 1998, 18(4), 461. 311 S. Nakamura, (Tsukuba, Ibaraki 305-8565, Japan).Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 312 E. E. Belyaeva, A. V. Ershov, A. I. Mashin, N. I. Mashin and N. K. Rudnevskii, J. Anal. Chem. (Transl. of Zh. Anal. Khim.), 1998, 53(6), 561. 313 J. H. Shi, K. Jiao and T. Liu, Fenxi Huaxue, 1998, 26(1), 122. 314 W. Li, G. Ascenzo, R. Curini, G. M. Gasparini, M. Casarci, B. Mattia, D. M. Traverso and F. Bellisario, Anal. Chim. Acta, 1998, 362, 253. 315 V. N. Mitkin, S.V. Tkachev, P. P. Semjannikov, V. M. Grankin, A. A. Galitsky, V. V. Moukhin, V. P. Demidov, V. L. Pasechnik, Yu. A. Fedorov and A. B. Alexandrov, (Inst. Inorg. Chem. Siberian Branch, RAS, Novosibirsk 630090, Russia). Presented at Analitika '98, Midrand, Gauteng, South Africa, October 12± 14, 1998. 316 X. G. Ren, Lihua Jianyan, Huaxue Fence, 1998, 34(4), 147. 317 N. M. Hepp, J. AOAC Int., 1998, 81(1), 89. 318 J. Yao, S. Qin, M. Ma, F. Zhou, Z. You and Y. Zhang, Huaxue Shijie, 1997, 38(3), 153. 319 S. L. C. Ferreira, A. S. Queiroz, M. G. A. Korn and A. C. Spinola Costa, Anal. Lett., 1997, 30(12), 2251. 320 O. M. Trokhimenko and N. F. Falendysh, J. Anal. Chem. (Transl. of Zh. Anal. Khim.), 1998, 53(5), 416. 321 I. D. Brindle, R. McLaughlin and N. Tangtreamjitmun, Spectrochim. Acta, Part B, 1998, 53, 1121. 322 R. E. Wolf, At. Spectrosc., 1997, 18(6), 169. 323 D. Amarasiriwardena, K. Sharma and R. M. Barnes, Fresenius' J. Anal. Chem., 1998, 362(5), 493. 324 Y. Z. Zheng, X. Wu, Y.W. Gao and X. M. Cao, Fenxi Shiyanshi, 1997, 16(4), 57. 325 E. Bakowska, (Hewlett-Packard Co., Wilmington, DE 19808, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 326 M. C. Yebra and P. Bermejo, Talanta, 1998, 45(6), 1115. 327 J. Yao, Z. B. Xiao and F. Q. Zhou, Lihua Jianyan, Huaxue Fence, 1998, 34(10), 458. 328 V. Hoffmann, M. Kunstar, R. Dorka, J. Werner, G. Behr, R. Jaehrling and D. Schiel, (Inst. Solid State and Materials Res., 01171 Dresden, Germany).Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 329 S. Saito, T. Tsugoshi, K. Furuya, Y. Kudo, M. Mishima, H. Takahara, T. Adachi and K. Sakai, Anal. Sci., 1997, 13(Supplement), 21. 330 K. Song, H. Cha and J. Lee, J. Anal. At. Spectrom., 1998, 13(10), 1207. 331 M. Y. Shiue, Y. C. Chan, J. Mierzwa and M. H. Yang, J. Anal. At. Spectrom., 1999, 14(1), 69. 332 P.Hayumbu and D. M. Sikabbubba, Analysis for heavy elements in commercial phosphate fertilizers and coal ash using X-ray Øuorescence spectrometry. Harmonization Health Relat. Environ. Meas. Using Nucl. Isot. Tech., Proc. Int. Symp. 1996, International Atomic Energy Agency, Vienna, Austria, 1997, 597±603. 333 J. Ma, Fenxi Ceshi Yiqi Tongxun, 1997, 7(3), 165. 334 M. Huang and A. Masuda, Fenxi Kexue Xuebao, 1998, 14(1), 1. 335 D. G. Graczyk, A. M. Essling, E. A. Huff, F. P. Smith and C.T. Snyder, Light Met. (Warrendale, PA.), 1997, 1135. 336 S. Anderson and A. Schleisman, (Air Liquide Electronics Chemicals and Services, Inc., Dallas, TX 75243, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 337 D. Hampe and O. Piringer, Food Addit. Contam., 1998, 15(2), 209. 338 Y. W. Heo, J. I. Gil and H. B. Lim, Anal. Sci. Technol., 1998, 11(4), 311. 339 K. Zih-Perenyi, A. Lasztity, Z. Horvath and A. Levai, Talanta, 1998, 47, 673. 340 M. P. Carril, M. S. Corbillon and J. M. Madariaga, Accredit. Qual. Assur., 1997, 2(6), 301. 341 J. Xue and Y. Zhao, Guangpu Shiyanshi, 1997, 14(5), 60. 342 F. G. Smith, (CETAC Technologies Inc., Omaha, NE 68107, USA). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. J. Anal. At. Spectrom., 1999, 14, 1937±1969 1967343 P. L. Buldini, A. Mevoli and J. L. Sharma, Talanta, 1998, 47, 203. 344 C. Rigby and I.S. Brindle, J. Anal. At. Spectrom., 1999, 14(2), 253. 345 M. Krapp and B. Neidhart, GIT Labor-Fachz., 1998, 42(10), 987. 346 O. Abollino, M. Aceto, M. C. Bruzzoniti, E. Mentasti and C. Sarzanini, Anal. Chim. Acta, 1998, 375(3), 293. 347 X. G. Ma, Y. C. Liang, W. Q. You and Z. X. Zhang, Fenxi Huaxue, 1998, 26(9), 1097. 348 S. Imai, M. Hayashi, A. Yonetani and Y. Hayashi, Anal. Sci., 1998, 14(3), 589. 349 F. Chartier, M. Aubert, M. Salmon, M. Tabarant, Thi Bich and H.Tran, (CEA/SACLAY, DCC/DPE/SPCP/LAIE, 91191 Gifsur- Yvette, France). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 350 J. R. Pretty, D. C. Duckworth and G. J. Van, Anal. Chem., 1998, 70, 1141. 351 J. Pretty, D. Duckworth and G. Van Berkel, (Oak Ridge Natl. Lab., Oak Ridge, TN 37831-6375, USA). Presented at 46th ASMS Conference on Mass Spectrometry, Orlando, FL, USA, 31 May±5 June, 1998. 352 A. E. Eroglu, C. W. McLeod, K.S. Leonard and D. McCubbin, Spectrochim. Acta, Part B, 1998, 53, 1221. 353 S. Sturup, H. Dahlgaard and S. C. Nielsen, J. Anal. At. Spectrom., 1998, 13(12), 1321. 354 C.-S. Kim, C. K. Kim, J. Y. Yun and B. H. Rho, (Radiological Environ. Dept., Korea Inst. Nuclear Safety, Taejon, 305-338, South Korea). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 355 S.-K. Lee, Y. J. Kim, J. Y. Yun and B. H. Rho, (Radiol. Environ. Dept., Korea Inst.Nuclear Safety, Taejon 305-338, South Korea). Presented at 1998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 356 A. E. Eroglu, C. W. McLeod, K. S. Leonard and D. McCubbin, J. Anal. At. Spectrom., 1998, 13(9), 875. 357 Y. Liang, W. S. White, L. Yao and R. E. Serfass, J. Chromatogr., A, 1998, 800(1), 51. 358 S. F. Wolf, J. Radioanal. 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Zandian, D. D. Edwall, R. E. De Wames, P. S. Wijewarnasuriya, J. M. Arias, S. Sivananthan, M. Berding and A. Sher, J. Electron. Mater., 1998, 27(6), 595. 380 V. V. Gerasimov, V. M. Mitsa and A. A. Aivazov, Poverkhnost, 1998(3), 49. 381 Q. L. Guo, J. P. Zhang and Z. P. Yang, Guangpuxue Yu Guangpu Fenxi, 1998, 18(1), 67. 382 R. Yue, Y. Wang, C. Chen and C. Xu, Zhenkong Kexue Yu Jishu, 1998, 18(1), 50. 383 S. Muhl, A. Gaona-Couto, J.M.Mendez, S. Rodil, G. Gonzalez, A. Merkulov and R. Asomoza, Thin Solid Films, 1997, 308, 228. 384 B. C. Smith and H. H. Lamb, J. Appl. Phys., 1998, 83(12), 7635. 385 K.-S. Liu, T.-F. Tseng and I.-N. Lin, Appl. Phys. Lett., 1998, 72(10), 1182. 386 J. J.-K. Chang, K. E. Johnson, H. Kawayoshi, P. Ling and M. Strathman, IEEE Trans. Magn., 1998, 34(4, Pt. 1), 1567. 387 W. Frank, A. Schindler and H.-J. Thomas, Fresenius' J. Anal. Chem., 1998, 361(6±7), 625. 388 D. Zhao and Y. Jin, Huanjing Wuran Yu Fangzhi, 1997, 19(2), 39. 389 Z. Q. Wu and C. Y. 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N. Guo, S. N. Renfrow, Z. Y. Zhao and J. M. Anthony, Appl. Phys. Lett., 1998, 72(23), 3008. 399 K. Fujimoto, M. Ito, M. Shimura and K. Yoshioka, Bunseki Kagaku, 1998, 47(3), 187. 400 G. Bercowy, A. Saint, L. Moore and D. N. Jamieson, (GBC Sci. Equipment Inc., Illinois 60004, USA). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 401 D. Romero, J. M. Fernandez Romero and J. Javier Laserna, J. Anal. At. Spectrom., 1999, 14(2), 199. 402 P. K. Chu, B. W. Schueler, F. Reich and P. M. Lindley, J. Vac. Sci. Technol., B, 1997, 15(6), 1908. 403 B. Wiedemann, K. Bethge, E. Buhrig, C. Frank, C. Hannig, K. Deus and G. Gaertner, PTB-Ber. ThEx-Phys.-Tech.-Bundesanst., 1997(PTB-ThEx-3), 125. 404 H. Kipphardt, S. Valkiers, F. Henriksen, P. De Bievre, P. D. P. Taylor and G. Tolg, Int. J. Mass Spectrom., 1999, 189(1), 27. 405 A. Schleisman, D. Bollinger, B. Tillotson and S. Anderson, (American Air Liquide, Dallas, TX, USA). Presented at 25th FACSS, Austin, TX, USA, October 11±15, 1998. 406 T. Kumamaru, H. Notake, S. Q. Tao and Y. Okamoto, Anal. Sci., 1997, 13(6), 885. 407 R. M. Barnes, A. Krushevska, E. D. Prudnikov and Y. S. Shapkins, (Lederle Graduate Res. Center Tower, Univ. Massachusetts, Amherst, MA 01003-4510, USA). Presented at 1968 J. Anal. At. Spectrom., 1999, 14, 1937±19691998 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, USA, January 5±10, 1998. 408 M. Motelica-Heino, P. Chapon, P. Le Coustumer and O. F. X. Donard, (Lab. Chim. Bio-Inorg. et Environ., EP CNRS 132, 64000 Pau, France). Presented at European Winter Conference on Plasma Spectrochemistry, Pau, France, January 10±15, 1999. 409 X. Pan and R. K. Marcus, Mikrochim. Acta, 1998, 129(3±4), 239. 410 A. Makishima, E. Nakamura and T. Nakano, Anal. Chem., 1997, 69(18), 3754. 411 X. M. Lu, A. Ji and G. Y. Tao, Fenxi Huaxue, 1997, 25(2), 178. 412 Z. H. Zhang, J. Zhang, Y. Chen, C. H. Tu and J. D. Zheng, Anal. Chim. 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ISSN:0267-9477    

DOI:10.1039/a908094e

出版商:RSC    

年代:1999

数据来源: RSC