JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 33713 ATOMIC SPECTROMETRY UPDATE-INDUSTRIAL ANALYSIS METALS CHEMICALS AND ADVANCED MATERIALS John Marshall* and John Carroll ICI plc Wilton Research Centre P.O. Box 90 Middlesbrough Cleveland UK TS6 W E . James S. Crighton BP Research and Engineering Centre Chertsey Road Sunbury on Thames Middlesex UK TWI 6 7LN Charles L. R. Barnard Department of Physical Sciences Glasgow Caledonian University Cowcaddens Road Glasgow UK G4 OBA Summary of Contents 1. Metals 1.1. Ferrous Metals and Alloys 1.2. Non-Ferrous Metals and Alloys Table 1. Summary of Analyses of Metals 2. Chemicals 2.1. Petroleum and Petroleum Products 2.1 .l. Crude oil and fractions 2.1.2. Lubricating oils 2.2. Organic Chemicals and Solvents 2.2.1. Chemicals 2.2.2.Solvents 2.2.3. Catalysts 2.3. Inorganic Chemicals and Acids 2.4. Nuclear Materials 2.5. Process Analysis and Automation Table 2. Summary of the Analyses of Chemicals 3. Advanced Materials 3.1. Polymeric Materials and Composites 3.2. Semiconductor Materials 3.2.1 Silicon based materials 3.2.2. Gallium arsenide based materials 3.2.3. Cadmium mercury telluride and indium phosphide based materials 3.3. Glasses Ceramics and Refractories 3.3.1 Glasses 3.3.2 Ceramics and refractories Table 3. Summary of Analyses of Advanced Materials This Atomic Spectrometry Update is the latest in an annual series appearing under the title of ‘Industrial Analysis’. The structure of the review is broadly the same as in previous years. Reports on the analysis of catalysts have been moved from the ceramics and refractories section into the chemicals section of the review.It is hoped that this categorization will better reflect the interest in these materials in the petrochemicals industry. The year in which major developments in instrumental analytical chemistry begin can usually only be identified with the benefit of hindsight. It has been evident for some time that where sensitivity and selectivity are required mass spectrometric techniques have begun to dominate the field of atomic spectrometry. Pressures on industry to improve productivity have favoured rapid multi-element techniques such as ICP-MS and the advent of a viable solid sampling option in LA has provided a very powerful tool for product and process investigation.The identification of chemical form continues to grow in importance and the use of atomic spectrometry coupled with chromatography has become a significant area of research in the chemicals industry. Surface analysis techniques based on MS (e.g. SIMS GDMS) still make an enormous contribution to the characterization of semiconductors. However TXRF is now making a significant impact in this field as a consequence of the high sensitivity of the technique and its applicability to the non-destructive analysis of wafers and thin films. The advent of r.f. boosted GDs represents a promising development but it remains to be seen whether practical advantages over more conventional techniques such as WDXRF can be demonstrated in an industrial context. *Review Co-ordinator to whom correspondence should be addressed.338R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 1. METALS This section of the review covers the analysis offerrous and non- ferrous metals and alloys by analytical atomic spectro- metry. A summary of the methods for the analysis of metals is given in Table 1. The composition of the abstracts received for review was approximately one third for ferrous metals and the remainder for non-ferrous. 1.1. Ferrous Metals and Alloys The vast majority of the publications received described modifications to sample preparation methods. There is considerable emphasis on the presentation of the sample in a form that presents the best opportunity for near interfer- ence-free determination. As might be expected this is particularly the case for AAS and ICP-AES.The use of interference inhibitors in AAS has received further attention for the determination of Cr and Mn in steel. It was observed that guanidine and formamide and also ethylenedamine and ethanolamine proved to be effective inhibitors for the interference of transition metals in the determination of Cr and Mo in steel (93/1114 93/11 15). In a similar vein the same group reported that hexamine urea and glycine were effective in eliminating inter-element effects in the determi- nation of Mo in steel (93/2670). An automatic sample treatment system for introduction of hydride forming and non-hydride forming elements has been described which uses on-line acidification and hydride generation (93/C3067). This approach allowed both types of elements to be introduced into the ICP via a nebulizer.The use of combined methods including ion chromato- graphy and various forms of microcolumn preconcentration continue to be reported as these approaches offer the benefits of matrix separation and signal enhancement. The determination of Co in steel has been carried out successfully using such a method (93/2726). Cobalt was preconcentrated on an ammonium tetraphenyl borate ion-pair column supported on naphthalene using 2-( 5 bromopryridazol-5- diethylamino phenol) chelation and was then eluted with DMF. The linear range was reported to be 1 - 10 pg of Co in 5 ml of eluate and typical precision for the method was of the order of 1 Yo relative. A chromatographic separation was employed for the determination of S in high-purity iron by ICP-AES (93/ 10 12).Sulfate was separated from the matrix elements on alumina microcolumns and S was determined at 180.73 nm with a detection limit of 0.3 ppm. A method has been reported for the determination of B in high-purity iron (92/44 17). The sample was dissolved in hydrofluoric acid and hydrogen peroxide and the residue fused with sodium and passed through an anion-exchange chromatography column. The adsorbed B was eluted with 2 mol dm-3 nitric acid and then evaporated to further preconcentrate the sample prior to analysis. Sequential ICP-AES instruments take a finite time to move between analyte wavelengths and this can be inconvenient when monitoring transient chroma- tographic peaks. This problem was overcome for the application of ion chromatography to nitric acid digests of iron and steel samples by adjusting the elution flow rate to match the ICP-AES spectrometer scanning rate (93/434).The search for more rapid methods of analysis for use in the quality control of steel production continues. The time taken for sampling and conveying samples to the laboratory is now becoming a significant proportion of the overall analysis time. It is possible to determine elements in steel by sampling dust particles above the molten metal (93/783). A sub-10 pm particulate fraction was separated from the bulk dust above molten steel with a cyclone system immediately prior to direct introduction into a flame atomic absorption spectrometer. The Mn content of this fraction was found to correlate well with the bulk Mn content of the steel.There has been particular interest shown in the period under review in the application of spark-based techniques for the direct analysis of solid steel samples. The relative merits of spark ablation ICP-MS and GDMS for the characterization of 20 elements in an NIST steel sample have been compared (93K1330). It was reported that GDMS was preferred on the basis of superior sensitivity. I-fowever in another study of the analysis of steels spark ablation ICP-MS was compared with GDMS using a similar IviS detector in both systems (92/4605). It was reported in this case that the relative sensitivity for elements and precision (approximately 3% relative) for the spark ablation system were similar to those obtained with the GDMS instrument.In addition spark ablation ICP-MS exhibited relatively few spectral interferences from polyatomic spe- cies presumably as a result of more efficient atomization. The determination of V in ferrovanadium by spark ablation ICP-AES has also been reported (92/4627). Samples were re-melted and diluted with iron to avoid fracturing prob- lems and it was reported that under these conditions spark ablation at a high repetition rate yielded a precision for V of 0.3% relative. In another application of spark ablation ICP- AES the analysis of steels was investigated (93/1254). It was noted that the spark discharge generated ultra-fine dust particles and by careful control of plasma parameters results could be obtained which were in good agreement with conventional methods.The analysis cycle time was reduced to 90 s using this approach. Laser ablation is now receiving significant attention as a means of introducing solid steel samples for ICP-MS. A comparison of laser and spark ablation procedures has been rnade (93K1325). It was observed that the laser-based procedure offered a larger linear dynamic range because of the ability to ablate a smaller amount of sample than the spark device. The use of the laser in Q-switched mode was found to prevent the spread of sample from the ablation crater. Laser ablation ICP-MS can also be used for depth profiling of solid steel samples (93/23 10). An investigation was made of the effect of laser power pulse repetition rate and optical focusing parameters on the resolution of depth profiles obtained using the technique.It was observed that the best resolution was achieved when the laser was cle-focussed by 10 mm. It was found that ablation rates differed for low and high boiling-point elements. Laser ablation ICP-MS has been applied to the determination of a range of elements in steels (93/2402). A Q-switched Nd:YAG laser was employed for this work and it was found that this device generated particles of the order of 0.02 pm in diameter. It was noted that selective vaporization of 1 olatiles was possible but at a relatively low sensitivity. IJsing an integration time of 0.18 s detection limits were in the range 0.01 ppm (Nd) to 5.5 ppm (Ni). Laser sampling can also be used in AES by direct observation of character- istic radiation emitted from the plasma plume generated by iinteraction between the beam and the sample (93/3 153).In tlhis study time-resolved spectra obtained in a nitrogen atmosphere were acquired for the determination of C in steel. Analytical precision for the determination was 1.6% relative and an LOD of 65 ppm was reported. Glow discharge sources are increasingly being used for the direct analysis of steels. The effect of GD anode geometry on sampling for AES has been the subject of investigation (93/1019). It was found that the electric field distribution was influenced by anode geometry and that the flatness of the crater bottom was related to the diameter of the anode. Operation under optimized conditions with a ceramic slpacer was reported to yield a flat crater profile. The system was applied to the determination of Mn in steel.In an interesting application of GD-AES a neural network wasJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 339R Element Matrix Ag Super alloy Ag High-purity copper Table 1 SUMMARY OF THE ANALYSES OF METALS Technique; atomization; analyte form* AE;ICP;L AA;F;L Al Iron and Steel Al Steel Al Aluminium targets As Nickel-based alloy As Nickel As Nickel Alloy Au Gold silver copper alloys B High-purity iron B Steel slag B Steel B Steels Bi Iron and Steel C Steel C Steel AA;ETA;L MS;LA;S X-ray emission; -;S AA;F;G AA;ETA;L AA;F;G XRF-;S AE;ICP;L AE;ICP;L AA;F;L MS;ICP;L MS;ICP;L AE;LA;S MS;GD;S 9312590 9312799 9214638 Sample treatmentlcomments Reference 931735 9313 135 Adsorption onto sulfhydryl cotton; detection limit of 0.I pg g-I Ag reported Sample was dissolved in nitric acid preconcentrated on a mercapto-acetoxy cellulose column and eluted with ammonium thiocyanate; recoveries were reported in the range 95-105% with RSD of 1.95% (n= 11) Sample was dissolved in aqua regia filtered and Al determined as acid solublelinsoluble fractions; detection limits were 0.33 ppm for acid soluble A1 and 0.1 ppm for acid insoluble Al and RSDs were 3.25% at 12.5 ppm and 2.8% at 13.3 ppm respectively Analysis of NIST SRMs 126 1A and 1263A; detection limits reported in the low ppm range Samples irradiated with intense femtosecond optical pulses were found to emit strong K-alpha lines with similar lifetimes in nitric and hydrofluoric acids; a strongly acid cation-exchange microcolumn was used to provide continuous-flow matrix isolation Sample was dissolved in 0.2 mol dm-’ nitric acid; Zeeman ETAAS gave RSDs for BYG 801-20 and BYG 805-20 of 4.42 and 8.98% respectively hydrofluoric acids; BCS CRM 346 IN nickel alloy analysis gave LOD 0.5 ppm As (ie.250 pg absolute) with RSD 3.5% for a 10 ppb ASV solution (n = 6). Flat and oblate samples were prepared polished and sectioned for enegry dispersive analysis; mixtures of gold (80-95%) silver (4-1 5%) and copper ( 1 - I 5%) were used as standards Dissolution with hydrofluoric acid and hydrogen peroxide and sodium fusion of the residue followed by anion-exchange chromatography and elution with nitric acid; RSDs of 1.9 and 8.5% were reported for the determination of B in iron disilicide and high-purity iron respectively with detection limits of 0.01 to 0.05 ppm Disaggregation in the solid state followed by aqueous extraction and alkaline extraction with sodium carbonate and zinc oxide; minimum determination level was 5 ppm Peroxide and phosphoric-sulfuric acid digest with nitrobenzene extraction; recoveries better than 96% were reported with RSD of 3% Rapid (25 min) high-pressure microwave digestion; Accuracy and precision for 1-10 ppm B in steel was satisfactory Pyrolytic graphite coated graphite tubes were used for ETV sample introduction of acid digests; the appearance time for Bi in nitric acid was later than for hydrochloric acid and nickel was found to increase the Bi signals in nitric acid; detection limits were typically 50 times better than those for conventional nebulization onto the sample and time resolved spectra were measured in nitrogen atmospheres; the RSD was 1.6% and a detection limit of 65 ppm was reported sensitivity factors with determinations below 20 PPm 9214438 Samples were digested in a sealed microwave vessel Microwave assisted digestion in nitric and Plasma was formed by focusing an Nd:YAG laser Neon as working gas gave improved relative 93lCI 333 931733 9311 638 92/44 13 92/44 1 7 931 I247 9312236 9312287 931786 9313153340R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 1 SUMMARY OF THE ANALYSES OF METALS-continued Cr Steel Cr Steel AA;FL XRF-;S Mn Mo Mo N Ni 0 P P Steel Tungsten Steel Steel Titanium metal Steel Nickel alloys Super-alloys AA;FL AA;F;L AA,F;L MS;GD;S AA;F;L MS;GD;S AFETA;L AE;ICP;L c u Aluminium alloy c u Lead and zinc metal cu Copper nickel alloy c u Titanium metal Fe Lead and zinc metal Fe Tin-plate In Zinc metal Mg Aluminium alloys Mn Molten steel Mn Steel AA;-;L AE;ICP;S MS;-:S AA;FL AE;ICP;S MS;SI;S AA;F;L AE;ICP;L AA;FL AE;GD;S Technique; atomization; Element Matrix analyte form* Sample treatmentlcomments c o Steel and alloy AA;FL Preconcentration of Co on an ammonium tetraphenylborate ion-pair column supported on naphthalene using 245 bromopyridazol-5- diethylamino phenol) chelation elution with DMF; linear range 1-10 pg in 5 ml DMF RSD 1 Oh S,ample was dissolved in hydrochloric acid containing guanidine and formamide as interference inhibitors Accuracy of XRF measurement was found to depend on the relationship between the alpha coefficient and composition; an evaluation was made of 456 alpha-computing algorithms for the determination of Cr Oa-line electrolytic dissolution of solid metal with FI transfer of sample to AAS for direct analysis Direct insertion of sample in a graphite cup; detection of copper at ppb level with minimized interferences and RSDs of 5-20?40 sputtering; initial copper content was 75-85% at 870 K using 3 kV Xe+ bombardment but after 100 nm was removed this dropped to 6O-7O0h and then remained constant down to 1000 nm Extraction of Cu as APDC complex in diisobutyl ketone in hydrochloric acid containing tetrafluorohydroboric acid; interference from iron was minimized Surface aggregation of copper was measured with As for Cu; detection of iron at ppm level Corrosion of tin-plate was correlated with microscopic distribution of iron near the outer surface and oxygen was measured to a depth of 1-2 pm with this technique Sample was dissolved in nitric acid evaporated to dryness adjusted to pH 3.5 and extracted with 1- phenyl-3-methyl-4-benzoyl-5-pyrazolone IBMK the limit of detection was 0.07 ppm with an RSD of 2.0% ( n = 5 ) for 0.6 ppm In Alcid dissolution; RSD 1-3% Fine particles were separated from the bulk dust above molten steel with a cyclone prior to direct introduction into the flame; the sub-10 pm fraction correlated well with the Mn content of the steel distribution and the larger diameter of the anode the flatter the crater bottom.The use of a ceramic spacer and optimized discharge parameters were also shown to result in a flat crater profile A!; for Cr Saimple was mixed with 50% emulsifying agent Ainode geometry was found to affect electric field calcium carbonate and phosphoric acid; linear range 0-40 ppm Mo Salmple was dissolved in hydrochloric acid containing hexammine urea and glycine as interference inhibitors Aii for C A!i for CU A!i for C Diissolution in nitric acid; laser excited atomic fluorescence gave a linear range from 0.1 pg to 8 pg with analytical precision of 18% added to form the molybdophosphoric heteropoly acid which was extracted into butyl actetate prior to back extraction into ammonia 0.5 ppm with recoveries of 96-99% Sample was dissolved in nitric acid and molybdate Diissolution of sample in nitric acid; linear range to AA;F;L Pb Lead brass Reference 9312726 9311 114 9312 7 79 92/43 13 931805 9312628 9313093 931805 931863 931550 921435 1 931783 931 10 1 9 9311 115 931665 9312670 93x1 333 93/3093 93lC1333 9312074 9313078 931662JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 341R Table 1 SUMMARY OF THE ANALYSES OF METALS-continued Technique; atomization; analyte form* Sample treatmentlcomments AE;ICP;L Sample was dissolved in a mixture of nitric and hydrochloric acids evaporated to dryness and re- dissolved in water; a detection limit of 5 ppm and standard deviations of 0.00 1-0.004% for the 220.35 nm line were reported Dissolution of sample in hydrochloric acid boiled for 15 min and re-dissolved in aqueous nitric- hydrochloric acid mixture; linear calibration to 500 ppb reported with Pb recovery of 10 1 % Solid copper chips were analysed directly at reduced pressures revealing three distinct types of lead i.e.surface grain and homogenous matrix lead Optimization of a modified Babington nebulizer and a cyclone-type condensation chamber for detection of Re line selection for S; detection limits were 0.92 1.13 and 3.19 pg ml-' of S at 180.73 182.04 and 182.63 nm respectively Separation of sulfate from iron and other matrix elements was achieved using a selection of alumina microcolumns; measurement of S at 180.73 nm gave a detection limit of 0.3 ppm As for Fe As for Pb; linear calibration to 500 ppb for Sn with Sample was mixed with 5% hydrochloric acid Closely matrix-matched standards used in study of recovery of 10 1 Oh containing nitric acid to destroy carbides and aluminium was added to enhance sensitivity in nitrous oxide flame; Ti was determined in the range 10- 100 ppm Element Matrix Pb Steel Reference 9311 176 Pb Copper wire AA;F;L 9312 147 93x920 Pb Copper Re Metals S Steel AA;ETA;S AE;ICP;L AE;ICP;L 931467 9214295 S High-purity iron AE;ICP;L 931101 2 Sn Tin-plate Sn Copper wire MS;SI;S AA;F;L 931863 9312 147 Ti Steel AA;F;L 9214730 Th High-purity tungsten MS;ICP;L 9312230 Sample was dissolved in hydrofluoric and nitric acids evaporated to dryness and redissolved in 1% nitric acid; recoveries were better than 90% and the limit of detection was (0.1 ppb; the RSD at 10 ppb Th was less than 5Oh As for Th Samples were re-melted and diluted with iron to avoid fracturing problems; spark ablation at a high repetition rate followed by ICP excitation gave RSD for V of 0.3% Solvent extraction of vanadium from the iron matrix with N-benzoyl-N-phenylhydroxylamine and the organic phase was transferred into perchloric acid; the standard deviation and detection limit were 0.03 and 0.1 pm respectively Elements separated as their fluoride precipitates and recoveries improved for trace element ranges; precision and accuracy were 2 and ~O/O respectively Cr and Mo also determined for Ca Fe Th and U respectively Artificial saliva; corrosion of Ni was most significant; Limits of detection were 10 20 0.05 and 0.05 ppb Direct sputtering of sample Influence of metallographic structure on the 155.7 nm C line intensity was reduced if the sample was heated to between 400 and 500 "C; RSDs in the range 1-5% Spark ablation with relatively small interference from polyatomic species was described; detection limits of less than 100 ppb were reported; RSDs = 3% Metals were ground by the bottle and bead method into slurries; recoveries for Ir Pd Rh were 80- 100% U High-purity tungsten V Ferrovanadium MS;ICP;L AE;ICP;L 9312230 9214627 V Steel AE;ICP;L 931756 REEs Steel AE;ICP;L 9311 130 Various (3) Dental alloys AE;ICP;L 92143 I9 Various (5) Refractory metals MS;ID;L 9214473 Various Alloys Various Steels AA;-;S MS;GD;S 9214526 9214572 Various Steels MS;ICP;S 9214605 Various Precious group metals MS;ICP;S 93lC86342R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 1 Element Various Various Various Various Various Various Various Various Various Various SUMMARY OF THE ANALYSES OF METALS-continued Technique; atomization; analyte form* AA;ETA;S Matrix Alloys Sample treatmentlcomments Salmple was sputtered directly onto a L'vov platform and analyte behaviour was normalized by adding nitric acid which converted all of the material to a single form Sample was digested in nitric acid introduced into an ion chromatograph coupled to a sequential ICP instrument RSD in the range 1.6-3.9% were reported Calibration data obtained from a GD diode-array spectrometer were used with step-wise multiple linear regression to train a neural network to correctly discriminate between the alloy classes Arid digestion of sample.Furnace-flame atomizer evaluated for analysis of impurities with RSDs of less than 0.14% Sample dissolved in nitric and hydrochloric acids for between 4 and 8 h; RSDs in the range 1.7-4.6% Metal coating thicknesses of 10-500 nm were measured with an accuracy of 0.5-2% Electrodeposition separated 90% of the matrix copper from the impurities in a warmed nitric and hydrochloric acid medium; isotope dilution was used to analyse NIST SRMs 394 and 395 Closed vessel microwave dissolution in aqua regia at 860 kPa was used to minimize contamination problems arc and liquid squeezed onto a copper mould. Pre-spark discharges of 20 s duration were applied at 550 V and 100 Hz and for the measurement cycle 350 V were applied detection was 0.5 ppm for trace elements in 99.99% pure silver Generation of ultra-fine dust particles with a spark discharge; the effect of plasma operating conditions were investigated and the analysis cycle time reduced to 90 s 0.5 ppb for Th and U and 0.01 ppb for Na and K respectively sensitivity.Cluster ions were the main source of interference but the method compared well with SSMS Careful control of nebulizer gas flow rate was used to minimize matrix ion effects Comparison of laser and spark ablation for solid sampling Spark ablation ICP-MS was compared with GDMS for conducting solids such as a 20 element NIST steel. The GDMS system was found to be the more sensitive of the two techniques Depth profiling of Al 0 and Si of samples exposed to different mineral acids Single set of relative sensitivity factors was used for all matrices with 30-50% accuracy covering ranges from 96 to ppb Sample preparation methods involving melting in an induction furnace pelletizing by direct powder compaction and preparation of beads from pre-oxidized materials were compared Spark ablation achieved with a thyratron triggered variable wave form source.The sample was then introduced to the ICP via a modified Meinhard nebulizer Dependence of background intensity upon chemical (composition was modelled for trace constituents 0.7 g of steel wire was melted for 20 s in a welding Sample was dissolved in nitric acid. The limit of Ion-exchange separation; detection limits were 2 and Dissolution procedure. RSDs of 15-2Oo/o at high Reference 93lC113 Iron and steel AE;ICP;L 93/434 Platinum Steels AE;ICP;L AE;GD;S 931682 931723 Copper zinc and nickel metals and alloys Aluminium alloys Metal coatings Pure copper AA;ETA;FL 931c9 5 3 AE;ICP;L XRF;-;S MS;ICP;L 9 3lC962 93/c977 931 1009 Platinum AA;ETA;L 931 1039 Steel AE;spark;S 9311087 Various High-purity silver Various Steel AE;ICP;L AE; I CP; L 9311 166 9311254 Various (4) High-purity tantalum Various High temperature alloys AE;ICP;L MS;ICP;L 9311256 93x1 3 13 MSiICPi- MS;ICP;S MS;ICP;S Various Steels Various Steels Various Steels 93/C 1323 93/C1325 931C 1330 MS;GD;S MS;GD;S 93lC1349 93/C15 18 Various (3) Steels Various Platinum XRF-;S 9311786 Various Ferro alloys MS;ICP;S Various Copper metal 931 1946 Various Nickel-based alloys XRF;-;S 9312034JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 343R Table 1 SUMMARY OF THE ANALYSES OF METALS-continued Element Matrix Various (3) Titanium alloys Various Titanium Various Steel Various Aluminium Various Copper and indium Various Aluminium and its alloys Various Steels Various (3) Steels Various Steels Various Low alloy steels Various Copper Various High-purity molybdenum Various (3) Tungsten alloys Various Steel Various (5) Steel and alloys Various High-purity copper Technique; atomization; analyte form* AE1aser;S MS;-;L MSGD;S AE;ICP;L MS;ICP;S MS;GD;S MS;ICPS MS;GD;S MS;GD;S MS;GD;S SIMS AE;ICP;L XRF;-;L Coprecipitation with indium hydroxide and masking of the titatnium with hydrogen peroxide; detection limits were 8.1 ppm for Fe 0.8 ppm for Cu and 1.4 ppm for Ni Sample machined and double etched with hydrogen peroxide containing etching.Preparation time was reduced from 3 h to 20 min and the pre- sputtering time from 1 h to 20 min Laser-induced emission spectral analysis applied to industrial and process quality control offered relative detection limits in the range 10-100 ppm Detection limits for Ag Cay Cd Fey Th TI U and Zn reported in the range 0.02-86 ppb; Precision for alpha emitters better than 0.4-10% (U) and Round robin study with an interlaboratory RSD of less than 17% Heated with 50% sulfuric acid on a sand-bath mixed with hydrogen peroxide and evaporated at 230 "C for 2-4 hours in a pressurized PTFE vessel; applicable to alloys with less than 0.5% Si Laser ablation instumental parameters optimized with respect to depth profiling; best resolution was achieved with 10 mm de-focusing.Ablation rates differed for low and high boiling-point elements removed from the surface. For N determination the ion chamber requires a 20 min evacuation to reduce the background. Before 0 is determined the argon must be purified with a zirconium oxide catalyst; LODs less than 20 ppm switched Nd:YAG laser; LODs were reported in the range 0.01 ppm (Nd) to 5.5 ppm (Ni) for an integration time of 0.18 s. The error was 5-10% for elements with an isotope content of 10-20 ppm Use of iron as basis for normalization of the relative ion yields for each analysed matrix. Relative ion yields ranged from 0.1 to 5 in argon and 0.2 to 2.5 for neon filler gases When the GD source was operated at 4 mA 1000 V with a jet type ion source a sample loss rate of 0.23 mg min-' was obtained for a gas flow of 0-1 1 min-'.with relative ion yields of 0.57 for Fe and 3.5 for Cr Washed rod-shaped sample was sputtered for 30 min for determination of metals and for up to 2 h when determining C 0 and C1 at ppb levels. RSDs of less than 3% were achieved structures and impurity composition for Al 0 and Si Automatic sample treatment system for introduction of hydride forming and non-hydride forming elements which used on-line acidification and hydride generation. Interference was insignificant for Ca up to 40 ppm 1 g of sample was digested in a mixture of nitric and hydrofluoric acids for 2 h; NIST SRM 898 was analysed using both palladium-magnesium nitrate and phosphate-magnesium nitrate matrix modifiers; RSDs were reported in the range 2.6-14.9% for Bi Pb Se Te and TI Nitric acid dissolution of sample; Zeeman ETA detection limits were 0.6 ppb for Cd and 160 ppb for Sb MSGD;S 0.5-5% (Th) For C determination contaminants need to be Application of LA for direct solid sampling using Q- Sections of alloys revealed a relation between AA;ETA;L AA;ETA;L Sample treatmentlcomments Reference 9 31203 8 9312065 9312075 9312 100 9312 193 9312 194 93/23 10 931240 1 9312402 9312904 9312908 931292 1 931297 1 9 3lC3067 9313079 9313 192344R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 employed for classification of steels and alloys based on multi-element analysis data (93/723). A GD diode-array spectrometer was used to generate calibration data and stepwise multiple linear regression was utilized to train the neural network to discriminate between classes of alloy.The manufacture of high silicon steel is characterized by the formation of a resistant surface scale (93/C 1349). Analysis for Al 0 and Si in steels was carried out by GDMS after the steel sample had been exposed for varying periods to different mineral acids. Depth profle analysis carried out after different pickling treatments revealed that there was a part of the surf-ace area that was rich in silicon and aluminium oxides which resisted acid removal and con- ferred brittleness on the steel. Steel samples have been analysed by GDMS following the application of different heat treatments including annealing hardening and tem- pering (92/4572). It was reported that the influence of metallographic structure on the 155.7 nm C line intensity was reduced if the sample was heated to between 400 and 500 "C.Low alloy steels have been analysed by GDMS using either argon or neon as the working gas (93/2904). Relative ion yields for analyte elements were normalized to the matrix response for iron. The variation in relative ion yield ranged from 0.1 to 5 in argon and from 0.2 to 2.5 when neon was used as the filler gas. Methods of sample preparation for the analysis of ferro- alloys by XRF have been evaluated (93/1786). These included re-melting in an induction furnace pelletizing by direct powder compaction and preparation of beads from preoxidized materials. Standards which had been previ- ously analysed by wet chemical methods were used for calibration purposes.The accuracy of XRF methods for the analysis of steels has also been examined from a fundamen- tal point of view (93/2779). It was found that the accuracy of the determination of Cr depended on the relationship between the alpha coefficient and sample composition. This was evaluated for 456 alpha-computing algorithms and it was found that those which employed constant influence factors could provide acceptable accuracy. 1.2. Non-ferrous Metals and Alloys The majority of abstracts received were concerned with the analysis of copper and to a lesser extent aluminium and associated alloys. Applications are summarized in Table 1 and selected developments are described in this section. Copper is a metal which is readily available in a high- purity form and sensitive techniques are required for the determination of impurities.Consequently plasma source MS is increasingly being applied in this field. The analysis of pure copper by spark ablation ICP-MS has been described (93/ 1946). A thyratron triggered variable waveform spark source was used to directly introduce ablated copper into the plasma but this resulted in instability of the discharge. However the addition of a modified Meinhard nebulizer in the sample introduction system allowed the detection of trace elements down to 1 ppm with RSDs in the range 1 - 10%. Pure copper has also been analysed using ID-ICP- MS (93/ 1009). Electrodeposition was used to separate about 90% of the matrix copper from impurities in a warmed nitric and hydrochloric acid medium.The ID technique was used to analyse NIST SRMs 394 and 395 (Unalloyed Copper). Glow discharge MS is particularly useful for samples that are conducting and can be easily shaped to fit the discharge cell. Thus GDMS has been applied to the determination of Cr and Fe in copper (9312908). A jet-type ion source was operated at 4 mA and 1000 V and a sample erosion rate of 0.23 mg min-' was achieved for a gas flow rate of 0-1 1 min-I. Relative ion yields for Cr and Fe were 3.5 and 0.57 respectively. A round robin study of the analysis of copper and indium metals by GDMS may also be of interest (93/2193). An interlaboratory RSD of less than 17% was reported. The distribution of Cu in a copper-nickel alloy was investigated using sputtered neutral mass spectrometry (93/2628).The surface aggregation of copper was measured directly by sample sputtering. The initial copper content was found to be 75-80% at 870 K using 3 kV xenon ion bombardment but after 100 nm had been removed this dropped to 60-70% and then remained constant to a depth of 1000 nm. Further work has been reported on the direct analysis of solid copper chips for Pb by ETAAS (93/C920). Operation at reduced pressures revealed the presence of three distinct types of Pb namely surface grain and homogenous matrix lead. Flame AAS is also useful for the analysis of high- purity copper if applied in conjunction with a preconcentra- tion procedure (93/3135). The sample was dissolved in nitric acid evaporated to dryness and was re-dissolved prior to preconcentration by passage through a mercapto- acetoxy-cellulose column.Analytes were eluted with am- monium thiocyanate. Recoveries were reported to be in the range 95-105% and the RSD for 11 replicate determina- tions was 1.95%. The application of a furnace-flame atomizer to the detection of impurities in copper nickel and zinc metals by AAS may also be of interest (93/C953). One of the more interesting methods applied to the analysis of aluminium alloys involved on-line electrolytic dissolution of the metal (92143 1 3). The sample preparation s,ystem was interfaced to a flame AAS instrument using flow injection sample transfer for the direct determination of Cu. It has been observed that irradiation of aluminium targets with intense femtosecond optical pulses produced X-ray emissions with similar lifetimes (93/2779).The strong K alpha line was employed for the measurement of A1 content. High-purity aluminium has been analysed by IDMS (93/2100). It was reported that the precisions obtained for the determination of alpha emitters such as Th and U were 0.5-5% and 0.4-10% respectively using this technique. Few abstracts were received concerning the analysis of precious metals in the year under review. A procedure has been described for the analysis of precious metals using ICP-MS with slurry sampling (93lC86). The metals were ground by the bottle and bead method and a suspension of the material was introduced directly into the ICP mass spectrometer for analysis. Recoveries for Ir Pd and Rh were reported to be in the range 80- 100%. A closed pressure rnicrowave dissolution procedure has been described for the preparation of platinum samples for analysis by ETAAS (9311039).The sample was dissolved in aqua regia at 860 k.Pa in a microwave bomb. It was claimed that this procedure minimized contamination problems. Microwave digestion was also employed for the determi- nation by AAS of As in nickel alloys (93/1638). The digestion involved the use of nitric and hydrofluoric acids in combination and was applied to the analysis of BCS CRM 346. The limit of detection for As was reported as 0.5 ppm (250 pg absolute) and the RSD for a 10 ppb AsV solution was 3.5% (n= 6). An atomic fluorescence method was described for the determination of P in nickel alloys (93/2074). Laser excitation was employed in conjunction with electrothermal atomization of the nitric acid digest of the sample.The linear range of the method was 0.1-8 pg. Finally high-purity molybdenum metal has been charac- terized using GDMS (93/2921). The sample shaped as a rod was washed in aqua regia rinsed with de-ionized water and dried. The rod was sputtered for 30 min for the determination of metals and for up to 2 h for the detection olf C C1 and 0 at ppb levels. Relative standard deviations of less than 3% were reported. It was noted that the determina- tion of Ti was difficult as a result of spectral overlap from molybdenum doubly charged species.JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 2. CHEMICALS 345R 2.1. Petroleum and Petroleum Products Atomic spectrometry has been used for elemental analysis within the petroleum industry for almost as long as the techniques have been in existence.If anything the impor- tance of trace element analysis of petroleum and petroleum products is increasing owing to environmental pressures and the realization that trace elements in crude oil can some- times provide useful source rock indicators. This area therefore continues to provide a rich source of research topics for workers in the field of atomic spectrometry and progress is summarized in Table 2. In addition Marshall (93/629) has published a review (68 refs.) of applications of AAS which although superseded to some extent by tech- niques such as ICP-AES continues to be widely used throughout the petroleum industry. 2.1.1 Crude oil and fractions Until recently only nickel and vanadium porphyrins were used to any extent for characterization of crude oils and to provide additional correlations to be used alongside the traditional biomarkers such as steranes and triterpanes.However the increasing availability of very sensitive multi- element techniques such as ICP-MS has opened up the possibility of utilizing other trace elements which could not previously be readily measured on a routine basis. Olsen et al. (93/C973,93/C1317) have determined up to 35 elements in crude oils and shown that of these Br Co Cu Fe Mn Mo Nd Sb Se and Sr can provide useful data on petroleum migration and source rock. Although ICP-MS has the sensitivity to detect many of these elements directly following simple solvent dilution of the crude oil sample some elements particularly the lighter ones suffer from severe polyatomic interferences arising from the organic matrix and solvent.Techniques such as FAAS and ICP- AES generally do not have sufficient sensitivity to allow direct analysis after solvent dilution. The most common sample preparation approach for these techniques involves wet ashing of the sample (92/4293). Thus Ca Cu Fe Mg Ni and Zn have been determined using FAAS by heating the sample with sulfuric acid ashing the residue at less than 500 "C digesting the residue in hydrochloric acid and diluting finally with water. Knapp (93/C984) has described two systems for pressure controlled high-temperature microwave decomposition. These were operated at pres- sures of 1200 psi using a microwave oven and at 600 psi using a focused microwave approach (in collaboration with Anton Parr KG and Prolabo respectively).It was reported that these systems could be used to decompose all organic materials including oils and plastics in a single-step proce- dure. The alternative approach of extraction of metals into IBMK is viable and has been reported for the determina- tion of Ni and Pb by ICP-MS (93/2902) and V using FAAS (93/C 1623). Whereas solution-based techniques such as those described above are well suited to the analysis of crude oils the characterization of oil shale kerogens requires information not only on bulk trace element concentrations but also on their distribution between the kerogen and minerals or bitumen. Mercer et al. (92/4465) have used a combination of NAA XRD and electron microprobe tech- niques to study the organic-inorganic associations of trace elements in shale kerogen.Several elements (As Co Mo Mn Ni Sb Se and Zn) were found to have some association with the residual mineral-kerogen phases (i. e. insoluble in toluene-methanol or hydrochloric-hydroflu- oric acid). Only Mn was found to have no significant contribution in the organic fraction which was separated by density. The remaining elements plus V might therefore prove useful for source rock correlations. An alternative method for the characterization of kerogens was described by Uden et al. (9312068). The method which required a minimum of sample pre-treatment involved pyrolysis GC coupled with MIP-AES. The technique allowed the charac- terization of compounds containing As C N 0 P S and Se opening up the possibility of utilizing compounds containing these elements as biomarkers.In some cases on- line alkylation was carried out to improve chromatographic behaviour by adding reagents to the pyrolysis probe or sample or by packing them into the injection port. For direct determination of trace elements in petroleum products the most convenient approach from the point of view of sample preparation involves dilution of the sample with an organic solvent. In the case of ICP based tech- niques the introduction of such solutions can give rise to plasma instability reduced sensitivity and increased inter- ference from spectral bands or molecular ions. An elegant solution to this problem involves the introduction of sample in the form of an emulsion (see also J.Anal. At. Spectrom. 1992 7 349R). This approach was applied to the determination of Al Cr Cu Ni Pb and S in oil products in the range 100-300 pg g-l (93/3123). Organic solutions can also cause problems in ETAAS as a result of sample spreading and penetration of the surface of the graphite atomizer tube. Curtius et al. (93/C95) have addressed this problem by adding 1 1-1 7 ml of propan-1-01 to homogenize and stabilize a two-phase mixture of 2 ml of water and 5 ml of kerosene (sample). This allowed the determination of Pb using ETAAS. The measurement of volatile metal species presents something of a challenge to analytical chemists in the petroleum industry. One such example is the determination of trace metals in liquified petroleum gas (LPG).The corrosion of aluminium heat exchangers by mercury in petroleum gas streams is a well known problem but other trace metal impurities can also cause problems by poisoning downstream catalysts. Mercury in natural gas has been measured on-line using an automated system comprising a gold-impregnated sand trap to preconcentrate gaseous mercury and atomic fluorescence spectrometry for detection (93lC69). However if the determination of other elements is also required the application of an on-line approach becomes less practical. Homeier et al. (92/4464) have described a method for the determination of As Cu Hg Pb and Sb in LPG. Elements were adsorbed onto Amberlyst- 1 5 a commercially available cation-exchange resin.Mer- cury was then extracted with 20% aqua regia and the resin was then dissolved in a sulfuric and nitric acid mixture prior to the determination of the other elements using ICP- MS and ETAAS. For techniques which require sample nebulization (e.g. FAAS ICP-AES ICP-MS) difficulites can be experienced with volatile analytes due to selective volatilization in the spray chamber. A direct injection nebulizer has been used in ICP-AES to overcome this problem (931C1453). Selective enhancement of analyte signals was avoided since the sample was nebulized wholly into the plasma. Bagdi et al. (93/1030) have studied the sample introduction and atomi- zation of volatile alkyllead compounds in FAAS and shown that whereas at high sample uptake rates the composition of the vapour approaches that of the liquid-vapour equilib- rium at low uptake rates the sample completely evapo- rates giving an equivalent response for all alkyllead compounds.Thus FAAS was used for the determination of lead in gasoline containing an unknown mixture of alkyl- lead compounds by maintaining a low sample uptake rate. The workers also showed by measurement at two different uptake rates that it it was possible to obtain a measure of346R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 Table 2 SUMMARY OF ANALYSES OF CHEMICALS Technique; atomization; Element Matrix analyte form* PETROLEUM AND PETROLEUM PRODUCTS- Ba Lubricating oil AA;F;L Ca Lubricating oil c1 Transformer oil CI Waste lubricating oil HI3 Natural gas MI3 Lubricating oil Mo Lubricating oil Ni Crude oil Pb Alkyllead Pb Alkyllead Pb Kerosene Pb Light hydrocarbons Pb Gasoline Pb Gasoline Pb Crude oil V Crude oil Zn Lubricating oil Various (8) Crude oil Various ( 5 ) Liquid petroleum gas Various (8) Oil shale kerogens Various Lubricating oils (wear metals) AA,F;L MS;ICP;L XRF-;L AF;CV;G AA;F;L AA or AE;F or 1CP;L MS;ICP;L MS;ICP;L MS;ICP;L AA;ETA;L AA;FL AA,F,L MSICP;L MS;ICP;L AA;F;L AA;FL AA;F;L Sample treatmenttcomments Sodium dodecanesulfonate and benzyltrimethylammoniumchloride added to samples to enhance atomization efficiency of air-acetylene flame Comparison of results obtained using direct solvent dilution (80:20 to1uene:methanol) with those obtained using sulfuric and nitric acid digestion in an autoclave ETV-ICP-MS used to screen waste oils for possible contamination by polychlorinated biphenyls; temperature programming used to differentiate organic and inorganic chlorine XRF used to validate results obtained using novel apparatus for determination of organic chlorine Automated system for on-line analysis utilizing gold impregnated sand traps to preconcentrate gaseous mercury down to 10 pg Hg As for Ca Use of matrix matching to remove interference on Mo determination by oil additives including calcium petroleum sulfonate and zinc dialkyldithiophosphate IBMK-nitric acid extraction procedure Speciation using ion-pair reversed-phase HPLC-ICP- MS; detection limits reported for inorganic Pb triethyllead chloride triphenyllead chloride and tetraethyllead of 0.37 0.14 0.17 and 3.9 ng respectively Speciation of alkyllead compounds using reversed- phase HPLC-ICP-MS; membrane drier used to desolvate mobile phase component solution with water and kerosene in order to improve stability and sensitivity with respect to pure organic solution Accurate determination of Pb in mixtures containing tetramethyl- and tetraethyl-lead was achieved by controlling volatilization during nebulization by adjusting uptake rate Propan- 1-01 added to form a homogenous three- Speciation and determination of alkyllead compounds by GC-AAS; detection limits reported for tetramethyllead and tetraethyllead were 0.1 and 0.25 ng respectively compounds with a limit of detection of 0.7 pg s-l and better than 5% RSD Ciipillary GC-ICP-MS used to speciate alkyllead As for Ni Extraction of V complex into IBMK with a limit of detection of 0.019 pg m1-I; interference from molybdenum reported AS for Ca Sample (20 g) heated with concentated sulfuric acid and the residue was ashed in a muflle furnace; the ash was digested with dilute hydrochloric acid and the solution reduced in volume and diluted prior to determination of Ca Cu Fe K Mg Na Ni and Zn Determination of As Cu Hg Pb and Sb at ppb levels by adsorption onto cation-exchange resin removal with acid eluent and detection with ICP-MS or ETAAS Determination of organic and inorganic associations of As Co Mo Mn Ni Sb Se and Zn Cobalt was used as an internal standard to reduce interference effects caused by lubricating oil additives and viscosity improvers MS or AA;ICP or ETA;L NAA or EPMA; -;S AEICP;L Reference 9315 142 93J1175 93tC3674 931 1 700 93lC69 9311 175 9214492 93129029 9214573 93lC57 93lC95 931 1030 9311933 93t2092 9312902 93lC1623 9311 175 9214293 92t4464 9214465 92t4606JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 347R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-canfinued Element Matrix Various (10) Lubricating oil SRMs Various (4) Marine lubricating oils Various Lubricating oil (wear metals) Various Petroleum products Various (10) Crude oil Various Lubricating oil (wear metals) Various Volatile hydrocarbons Various Ash deposits Various Lubricating oil (wear metals) Various (7) Kerogen Various (8) Waste oil Various Lubricating oils (wear metals) Various Lubricating oil (wear metals) Various (6) Oil products Various ( 1 3) Lubricating oil Technique; atomization; analyte form* MS;ICP;L AA;F;L AE;S;L AA;F and ETA;L MS;ICP;L AE;spark;S AE;ICP;L XRF;-;S XRF;-;S AE;MIP;S MS;ICP;L AE;spark;S XRF-;S AE;ICP;L AE;ICP;L ORGANIC CHEMICALS AND SOLVENTS- A1 Organic reagents AA;F;L A1 Pharmaceuticals AA;ETA;L Br Halogenated hydrocarbons MS; M I P;L C Alcohols CI Explosive AE;ICP;L M S; I C P; L Sample treatmentlcomments Isotope dilution analysis for wear metals (Ag Cr Cu Fe Mg Mo Ni Pb Sn and Ti in SRM 1084a and 1085a Treatment of sample with mineral acid to dissolve metal particles and use of IBMK and non-ionic surfactant and a solvent in the determination of Cr Cu Fe and Pb Analysis time reduced in emission spectrography by ashing the next sample using the heat released by the discharge during the current spectral acquisition petroleum industry; includes example methodology Study of trace elements (Br Co Cu Fe Mn Mo Nd Sb Se and Sr) as source indicators Sample introduction system and operating conditions modified to improve detection of wear particles larger than 1-3 pm Direct injection nebulizer used to eliminate bias caused by selective volatilization of analytes Determination of composition of ash deposits on the heated surface of an oil-fired boiler Samples were filtered through a membrane which was then analysed using EDXRF with a cadmium-I09 source; detection limits were in the ng g-' range Pyrolysis GC-MIP-AES used to characterize samples using biomarkers containing As C N 0 P S and Se Determination of Ag As Ba Cd Cr Hg Pb and Se by direct aspiration of sample after dilution; detection limits were in the range 5-50 pg m-3 for high mass elements (>80 u) Detection of metal particles (>45 pm) by placing sample on the flat surface of a rotating disk electrode and ashing in a furnace at 400 "C for 30 s Wear metals separated from oil and presented to the spectrometer as a layer of intermediate thickness between thin and saturated; matrix effects calculated using fundamental parameters nebulization of aqueous emulsions; errors reported of less than 5% for a concentration range 100-500 pg g-I in the oil with high degree of accuracy from ICP-AES data for 13 elements Review with 68 refs.of applications of AAS in the Determination of Al Cr Cu Ni Pb and S in oils by Sulfated ash content (e.g. ASTM D874) estimated Study of enhancement effects of organic reagents and surfactants in FAAS; sensitivity enhanced 1 O-fold using binary system with sodium dodecylsulfate Procedures for cleaning labware and for sample and reagent preparation for determination of A1 at ppb levels SFC-MIP-MS was used to determine halogenated hydrocarbons at trace levels; detection limit reported in the low pg range with calibration linear over 3 orders of magnitude; 5% RSD Tabulation of emission lines in the IR for methanol ethanol and propanol in an ICP source Negative ion detection mode used in the determination of trace levels of C1 in 1,3,5- triamino-2,4,6,-trinitrobenzene Reference 931C390 9 3/40 7 931475 931629 93fC9 73 9311 185 931C I 45 3 9311656 9311 888 9312068 931 2334 9 312 6 8 6 9 312 7 8 8 9313 123 9313344 92146 14 9313 156 9312070 931322 1 93fC325348R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Matrix c1 Chlorinated hydrocarbons c1 Halogenated hydrocarbons Cr Organic reagents c u Copper organo-complexes c u Solvents Fe Refined fats and oils Fe Pharmaceutical tablets Mn Terephthalic acid 0 Alcohols Pt Anti-cancer drug S Encapsulated drugs S Essential oil Si Siloxanes Sn Organotin compounds Sn Organotin compounds Sn Organotin compounds Sn Organotin compounds Sn Organic solvents and acids T1 Radio-pharmaceutical Yb Organic reagents Zn Anaesthetics Various (8) Solvents Various Pesticide residues drugs Various (I 1) Dicyclopentadienyl- magnesium Technique; atomization; analyte form* AA;ETA;L AE;ICP;L AE;ICP;S AE;ICP;L AA;ETA;L XRF-;S AE;MIP;L AA;F;L AE;ICP;L AA;ETA;L MS;ICP;L MS;ICP;L MS;ICP;L Interface described for GC or conventional nebulization sample introduction; GC-ICP-MS used to determine chlorinated hydrocarbons As as for Al; sensitivity enhanced 7-fold for Cr Injection of Cu pyrrolidin- 1 -yldithioformate into MS;MIP;L As for Br AA;F:L AA;FL supercritical carbon dioxide camer gas for 1.2- fold improvement in sensitivity compared with water Flow injection on-line extraction from water using bromoxine xylene or 1 :4 to1uene:xylene with membrane phase separator; enhancement factors of 10 and 16 respectively reported atomization at 2600 "C for detection of Fe in the range 5-100 ng g-I for 50°h oil-solvent mixture Determination of amount of iron oxide transferred from ink to tablet during manufacture; ink dissolved in nitric-hydrofluoric acids and Fe detected at 1-3 ppm level Direct analysis of powder using graphite rod sample insertion As for C Measurement of free cisplatin in samples by ETAAS Energy dispersive instrument used to monitor thickness of non-S-containing encapsulation coating on S-containing drugs Determination of acetylenic thiophenes by GC-MIP- AES; structure eludication in combination with GC-MS and GC-FTIR Determination of Si (siloxane in sulfuric acid process solution) using a nitrous oxide flame with standards prepared from octamethylcyclotetrasiloxane in sulfuric acid compounds collected on air monitoring cassettes using HPLC-ICP-AES organopalladium compounds; factors up to 19.1 were achieved HPLC-ICP-MS; limits of detection reported in the pg range Determination of tri- and tetra-organotin compounds using supercritical carbon dioxide as a camer for SFC-ICP-MS; detection limits were reported as 0.2-0.8 pg with RSDs of 1.3 and 3.4% respectively induced fluorescence signals using air-hydrogen flame isopropylether; detection limit was reported as 0.5 pg ml-I AA;F;L Use of L'vov platform with ashing at 1200 "C and Separation and determination of organotin Study of sensitvity enhancement using Speciation of organotin compounds using Study of effect of organic solvents and acids on laser TI.was extracted from aqueous solution using A s for Al; sensitivity enhancement 50-fold for Yb Indirect method for determination of lidocaine dicaine or procaine by formation of ion pair with zinc thiocyanide and extraction into 1,2 dichloroethane Preconcentration with rotary evaporator followed by detection of Cd Co Cu Fe Mn Ni Pb and Zn at ppb levels detector for GC magnesium oxide; PTFE was used as a Review of use of MIP-AES as element specific Salmple was oxidized in air at 100-500 "C to form AFFL AA;F;L AA;FL AA;FL AA;F;L AE;MIP;L AE;arc;S Sample treatmentlcomments Reference 9312066 9312070 92/46 14 931439 9 3x3059 931453 93lC 1439 93lC8 1 931322 1 93lC 1 92 9312822 9313309 93lC 1452 93lC340 931582 93lC 1 627 9312067 93/33 17 9311 155 92/46 14 9315 12 9214322 9214527 9214701 sublimating agent to improve detection limitsJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 349R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* MS;ICP;L Element Matrix Various Alkyllead compounds and halogenated hydrocarbons Sample treatmentlcomments Capillary GC-ICP-MS using modified torch and heated interface for the identification of compounds with boiling-points up to 320 "C; detection limits in ng g-I range Study of variation in magnitude of polyatomic interferences with instrumental operating conditions for xylene and propan-2-01 solutions Capillary GC-ICP-MS used to speciate alkyllead and alkyltin compounds and ferrocene and nickel diethyldithiocarbamate; absolute responses were in the low pg s-I range.pesticides using SFC-MIP-AES AES. Organochloride recoveries were 9 1 - 109% and organophosphate > 73%; carbamate recoveries were inconsistent New direct serial coupled r.f.generator claimed to be more efficient and stable for analysis of organic solvents Air-argon plasma used on commerical equipment for analysis of organic solutions (IBMK); Content of 50% air in the cooling gas gave a large reduction in carbon band and line emission and acceptable cyanide band emission levels nebulizer; matrix matched standards were prepared by adding EDTA chelates under buffered conditions after sonification to prevent precipitation; detection limits in the ng g-I range New MIP torch shown to overcome some limitations of capillary discharge tubes; splitless injection up to 1 pl possible; applications to compounds of Se Si and Sn described Review of optical systems for use with GC-MIP-AES; results presented for compounds containing Br C C1 F H and S; detection limits reported in the range 140-350 pg reagents in FAAS and ETAAS for sensitivity enhancement and matrix effect suppression Study of effects of 16 solvents on fluorescence intensity of Ca Cd Cu Fe Mg Mn Sr and Zn; solvents with moderate viscosity and volatility effectively increased intensity Study of effect of ten surfactants on sensitivity of various metals in AAS using an air-acetylene flame carbon dioxide argon or helium) via a hole in the lower electrode; the method was applied to Br C1 and I as well as to detection of metals Use of organic soluble platinum or palladium modifiers to increase maximum pyrolysis temperature for determination of As Bi Cd Pb Sb Se Te and Sn as dithiocarbamate extracts in IBMK Discussion of sample preparation procedures and chemical modification to eliminate interferences Novel gas sampling GD source for determination of C halogens and S compounds in gases; pg s-' mass flow levels SFC-MIP-AES with Cchelle spectrometer used for the separation and identification of metal porphyrins Supercritical fluid extraction of organometallics using carbon dioxide with or without methanol as co- solvent Separation and determination of halogenated Determination of pesticide residues using GC-MIP- Solutions (1 5% mlv) introduced via a V-groove Review (99 refs.) of uses of organic analytical Liquid nebulized into the plasma (air nitrogen Reference 93lC 1 3 93lC60 93lC85 93lC 1 79 93lC 199 93lC2 8 8 931508 Various Solvents MS;ICP;L Various Organometallic compounds MS;ICP;L Various Pesticide mixtures AE;MIP;L AE;MIP;L Various Pesticide residues Various Solvents Various Solvents AE;ICP;L AE;ICP:L Various (1 1) Penicillin G AE;ICP:L 931530 Various (3) Organometallic compounds AE;MI P; L 931604 Various (6) Various Various Various Various ( 1 1) Various (8) Various Various Volatile halogenated and sulfur compounds AE;MIP;L 931605 Organic reagents AA;F or ETA;L AF;ICP;L 931640 931689 Solvents Surfactants Organic solutions AA;F;L AE;spark;L 931790 93lC958 Solvents AA;ETA;L 931 1076 Metallothionein preparations Gases AA;F or ETA;L AE;GD;G 931 1 196 93lC1475 (non-metals) Various Porphyrins Various Organometallics AE;MIP;L MS;ICP;L 93lC 1488 93lC15333 50R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-confinued Element Matrix Various Solvents Various Diethyl ether Various Organic compounds Technique; atomization; analyte form* AE;MIP;L Various Potassium hydrogen phthalate MS;ICP;L Various Organometallic compounds MS;spark;S Various (4) Nickel naphthenate AE;ICP;L Various Organic solutions AE;ICP;L CATALYSTS- C c o c s Ga H Mo 0 Pt Pt Re Rh Activated carbon catalyst supports H ydrodesul furization catalysts Alumina based silver catalyst Zeolites Activated carbon catalyst supports H ydrodesul furizat ion catalysts Activated carbon catalyst supports Catalysts Automotive catalyst emissions Alumina catalysts Alumina catalysts Sample treatmentlcomments Reference AA;FL Study showed that the intensity of elements could be varied by up to a factor of 6 in FAAS by varying position of impact bead in the spray chamber; could be used to obviate dilution MS;ICP;L Small volumes of sample injected into flowing stream 9312056 (1-4 ml min-') of dilute nitric acid (2%); Detection limits reported in the ng ml-I range but could be improved using a membrane desolvator Series of heterocyclic aromatic and aliphatic compounds were used to test compound dependence of elemental response factors for C C1 F N and 0 in GC-MIP-AES; the maximum variation found was 6% RSD Eight trace elements were separated from the matrix using Chelex- 100 resin prior to analysis using ETV-ICP-MS; limits of detection were 1 - 10 S,amples hydrolysed with organic solvent-mineral 9311956 ng g-' acid system and then incorporated into graphite electrode or pyrolysed first Determination of Ca Fe Mg and Ni using an air-argon-cooled ICP in IBMK solvent Air-argon-cooled ICP used to determine trace elements in organic solutions; advantages claimed included reduction in carbon molecular bands and thus better detection limits and no carbon deposition on injector .SIMS or XPS;-;S SIMS SIMS AA;F;L SIMS or XPS SIMS SIMS or XPS AE;ICP;L AA;ETA; L AE;ICP:L XPS SIMS or RBS 931207 1 9312320 9 3/23 64 9313 129 9313 163 Surface C:O ratios and surface functional groups measured after different chemical treatments using XPS and SIMS S1,atic SIMS used to study surface concentrations and depth profiles of Co and Mo on titanium dioxide alumina catalysts; results correlated with catalyst activity Dynamic SIMS used to study disposition of Cs on the surface of the catalyst before and after heat treatment; No migration from the surface observed Treatment with hydrofluoric acid provided total Ga concentration; controlled digestion with hydrochloric acid allowed measurement of only non-framework Ga species A,s for C 931242 1 9312603 9312452 9313338 931242 1 As for Co 9312603 A 5 for C PI extracted into xylene using potassium butylxanthate from aqueous solution at pH 5.2-6.2; interference from nickel noted Piirticle samples were collected directly from an exhaust pipe and digested in 30% nitric acid; volatile fraction also collected using a series of impingers and absorption tubes butylxanthate from sulfuric acid solution alumina on electrically conducting aluminium support; Rh was deposited from solution as normal and information on Rh coverage thickness and chemical form was obtained Re extracted into solvent with potassium Model catalysts prepared consisting of film of 931242 1 9311 156 9313 177 9314305 931245 1JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 351R Table 2 Element Sn Various W E ) Various Various SUMMARY OF ANALYSES OF CHEMICALS-CO~Z~~U~ Technique; atomization; Matrix analyte form* Catalysts AA or AE;F or 1CP:L Zeolites XRF;-;S Catalysts SIMS Hydrogenation catalysts SNMS or XPS INORGANIC CHEMICALS AND ACIDS- Au B Ba Be Bi Ca Ca cw) Cr c u Silver nitrate Salts of tetrafluroboric acid Stronium nitrate Beryl samples Silver nitrate Sodium chloride Calcium fluoride-carbon black dispersion High purity strontium preparations Zinc tungstate crystals Pure soudium chloride c u Sodium chloride Ga Coal and coal fly ash Pb Silver nitrate Pb Sodium chloride Pd Copper anode slime AA;ETA;S AA;FL AA;F;L AE; 1CP;L AA;ETA;L AA;F;L AA;F;L AA;F,air-CzHz;L AE;-;S AE;ETA;L AA;F;L AA;ETA;SI AA;ETA;L AA;FL AA;-;L Sample treatmentlcomments Reference 9312 146 Sample was mixed with 3 ml hydrofluoric acid evaporated to dryness then heated in a pressure bottle at 180 "C for 3 h with 6 ml aqua regia; range 0.8-250 ppm Sn Wavelength dispersive istrument used to determine REE at 0.1-1% mlm level by calibration with standards prepared using zeolite matrix and pure oxides; inter-element effects were corrected for by using mass absorption coefficients Review (75 refs.) of applications of SIMS to the examination of heterogeneous catalysts Combination of techniques used to study in situ activation of amorphous alloys of Au Cu Ni Pd and Zr to form dispersed metal-zirconium dioxide catalysts 9214386 9312646 9312993 Trace Au was separated from the matrix using 2 mol 1-' HCI. After filtration the Ag was extracted using 6 ml of 55% tri-butylphosphate-chloroform solution.Recoveries were 95- 105% No matrix effects observed using a nitrous oxide-acetylene flame Study of interference effects in air-acetylene and nitrous oxide-acetylene flames. Experiments performed on the basis of a factorial design Sample was fused with NaF treated with HzS04 and heated to remove fluoride. The cooled residue was dissolved in concentrated HCI and diluted with 3% HCl prior to analysis Ammonium chloride was employed for the separation of Bi by precipitation from the matrix in the presence of EDTA Coprecipitation with Mg(N03)z dissolution of the precipitate with HCI addition of NH4Cl and NaOH solutions and extraction with diethyldithiocarbamate-butyl acetate the presence of the carbon black from DDDC and tetramethlenedithiocarbamates (TMeDc) with IBMK 1 .9-fold enhancement in the signal reported due to Extraction of CrV1 using in the form of compounds Buffer employed was C:BaO:La203 (90:5:5) Tungsten spiral electrothermal atomizer was used to introduce samples directly into a d.c.-arc plasma.Optimization of operational parameters was described. Results obtained showed good agreement with ICP-AES 4 g sample dissolved in 100 ml HzO boiled for 1.5 min and the precipitate washed with hot H20.The filtrate is then dissolved in 100 ml of H20 and 50 ml of the resulting solution mixed with 1 drop of concentrated HN03 and 0.2 g of xanthate cotton. The cotton is mixed with 1 ml of concentrated HCl and 0.5 ml of 1:1 HN03 and boiled for 5 min to desorb Cu Slurry sample introduction using nickel as chemical modifier. Calibration against aqueous standards possible. RSDs of 2.1-5.7% were reported for Ga at the pg g-' level As for Bi As for Cu Extraction procedure for Pd from matrix outlined 9311 143 931470 92/41 72 9313 155 921434 1 9214 5 38 9311 179 921429 1 931499 931307 9312 150 9311028 921434 I 931654 93/57 1352R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* AA;ETA;L Reference 92146 17 Element s c Se Si Zn Zn Various (6) Various Various Various ( 1 1) Various (9) Various (8) Various (9) Various (4) Various (4) Various (10) Various ( 5 ) Various (5) Various (8) Matrix Waste water Sample treatmentlcomments :Sample was diluted 20-fold and an aliquot evaporated to dryness to remove sulfuric acid; the residue was dissolved in 10% HCl shaken with cupferron and extracted with chloroform; Sc was determined in the aqueous phase Mercury-palladium chemical modifier was employed. ,O. 1 g of sample was decomposed in a silver crucible by fusing with 1 g of NaOH + NaClO and the resulting melt was dissolved in HCl 0.1 g of sample was dissolved by heating in I ml of HCl followed by 3 ml of HN03.The residue was dissolved in 5 mol I-' HCl solution. A burner rotation of 30 degrees was employed Sample preparation procedure employing ultrasound is described which was claimed to decompose oragno-zinc compounds Various systems were examined for the extraction of trace impurities Investigation of the preliminary partial or entire precipitation of the macro-components as ZnS Review ( 1 2 Refs.) Modified sllica-gel packed in column. Solution containing metals passed through column and eluted with perchloric acid Methods developed are suitable for determination of metal impurities in high-purity salts for crystal growth for scintillation and acoustic applications Sample dissolved in glycerol or ethylone glycol Samples were buffered to pH 5.7 using sodium acetate and metals were extracted in the organic phase of DDDC-IBMK Platinum or palladium chemical modifier required Coal fly ash Pure boron AA;FL AA;FL 9312 I34 93lC877 Zinc concentrates AA;F;L 9313 13 1 Brine and common salt AA;F;L 9313296 Aluminium salts AA;F;L AA;F;L MS;ICP;L AA;FL 9214323 High purity zinc compounds 9214324 Ultrapure reagents Alkali and alkaline earth salts 9214367 921459 1 Alkali metal halides AA;F;L 931469 Chromium(iI1) chloride Brine waters AA;F;L AA;FL 931474 931658 Sodium and potassium chloride potassium iodide High purity chemicals AA;ETA;L 9316 17 AA;ETA;L AA;F;L Metals extracted by APDC-MIBK.Detection limits in the ng g-' range for all elements 931652 Lithium salts and various inorganic salts Metals extracted with 1 -phenyl-3-methyl-4- Elements precipitated with ammonium bromide and Direct analysis of solution; magnesium nitrate benzoylpyrazolone-5 in IBMK.chelated with EDTA employed as chemical modifier; Zeeman-effect background correction 931684 931690 9317 16 Silver nitrate AA;ETA;L AA;ETA;L Silver nitrate Phosphate samples AE;ICP;L Acid digestion with HF-HNO,-HCI in PTFE closed vessel followed by the same procedure using perchloric acid (rare earths) 931757 Various (20) Various (12) Various Various Various Various Various ( I 3) Monogermane and monosilane Red phosphorus High purity phosphorus Strontium preparations High-purity bismuth AE;-:S AE;d.c.-arc;G AE;ICP;G AA;FL AA;ETA; L 931782 931796 931997 9311 119 9311 131 Impurities preconcentrated by distillation of matrix at Electrothermal atomizer used for preconcentration Influence of the matrix on the response for Ca Mg Trace impurities were extracted from the matrix 550 "C into an Ar flow and sample introduction into the ICP and Na was studied using methyltrioctylarnmonium chloride-chloroform production of high-purity acids bases and solvents separation and preconcentration of a variety of elements were examined Review of use of ICP-MS for monitoring the Various extraction systems for the selective High-purity process chemicals MS;ICP;L 93J2486 High-purity copper salts AA and AE;F and 1CP:L 93J2123JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 353R Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Technique; atomization; analyte form* AE;ICP;L Reference 9312724 Element Matrix Various (9) High-purity potassium nitrate Sample treatmenticomments (precipitation of the matrix solvent extraction and ion exchange) were optimized and evaluated on the basis of elemental spike recoveries and reproducibility Feasibility of various X-ray methods were examined for bulk analysis or individual particles Optimization of standard and sample preparation procedures for rapid and routine analysis Examination of the potential of the GDMS technique for the complete chemical characterization of fly ash to ppb levels Different methods for the preconcentration Phosphoric acid employed as a chemical modifier Investigation of effects of contaminant elements Samples were ashed (500-600 "C) and the ash was present in cyanide solutions calcined (1000 "C) and fused with CaC0,-NH4Cl at 1100 "C and dissolved in water - AE;XRFS AE; X R F; S MS;GD;S 9312746 93128 I9 9312933 Various Fly ash Various Fly Ash Various Coal fly ash Various (4) Zinc sulfate Various (4) Au metal plating solutions AA;ETA;L AA;F;L AA:F;L 9313272 9313 14 1 Various (2) Coke 9214405 Various (7) Fly ash AE;ICP;L 9314462 NUCLEAR MATERIALS- B Primary coolant B Uranium-zirconium alloy NP Enriched uranium solutions Pu Plutonium S Graphite Boric acid was determined by using the molecular band spectra of B,O type oxides Sample dissolved in H2S04-(NH4)2S04 Extraction procedure for 237Np was discussed Procedures described for the determination of Pu Reproducible and reliable sample preparation isotope ratios technique (high-pressure asher) was employed to simulate the operating conditions observed in the graphite packing of a nuclear power station Discussion of analytical figures of merit for the determination of 99Tc by ICP-MS Sample was decomposed in a PTFE pressure vessel with HCI and H202.Th was seperated by cation exchange using 1.5 mol 1 - I HCI Simple XRF method was developed for the determination of Th in aqueous solutions. The sample was introduced directly into the spectrometer in polythene bottles As for Th As for Pu Sample was decomposed in a PTFE pressure vessel with HCI and H202. Uranium was separated by ion exchange using 9 moll-' HCl preconcentrated U was fixed to the Re filament of the MS On-line separation of U from a variety of matrices using chelating ion exchange Optimization of plasma operating conditions for the determination of U in three organic solvents (xylene kerosine and benzene) was described. On-line solvent extraction employed to remove the matrix Performance of a hybrid K-edge-XRF analyser was discussed with reference to screening of nuclear materials.Details pertaining to matrix effects precision accuracy and detection limits were discussed Uranium matrix extracted using tributyl phosphate One step procedure for separation of Al Ti and Fe Laser ablation was employed for the direct Single bead of anion-exchange resin containing described semiquantitative determination of trace impurities in a uranium oxide reference material 9214390 AE;F;L IDMS MS;ICP;L TIMS;-;S 9311 153 9312060 92147 17 931333 1 AE;ICP:L - Tc Th High-purity titanium MS;ICP;L MS;ICP;L 9312244 9313 127 Th Aqueous solutions XRF;-;L 92/45 5 6 U Aqueous solution U Uranium U High-purity titanium XRF;-;L TIMS;-;S MS;ICP;L 9214556 92147 17 9313 127 9214556 U Spent nuclear fuels IDMS;-;S MS;ICP;L AE;ICP;L 931292 931834 U Sea-water U Organic solvents 9214 5 7 5 9311 827 Various (28) Uranium oxide Various Process liquors MS;ICP;L AE;XRF;L Various Uranium and sodium MS;ICP;L 931226 1 931580 9318 16 Various Purified uranium Various (3) Uranium AE;ICP;L AE;ICP;L Various Uranium oxides MS;ICP;L 931 1003354R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 2 SUMMARY OF ANALYSES OF CHEMICALS-continued Element Various Various (8) Various (3) Various ( 13) Various (3) matrices Various (25) Matrix Industrial waste water Uranium oxide matrices Uranium oxide Nuclear grade uranium compounds Uranium-aluminium Uranium oxide Technique; atomization; analyte form* MS;ICP;L MS;IDSS;L MS;ID;- XRF;-;S AA:ETA;L AE;ICP;L Reference 93/29 15 9312606 9312605 Sample treatmentlcomments Comparison of ultrasonic and pneumatic nebulization for determination of actinides Technique employed for the certification of a uranium oxide reference material 13ulk of the matrix was removed by ion exchange and a further extraction step was required to isolate the elements of interest !samples were prepared in the form of double layer pellets with starch as a binding agent.Standards were prepared in a uranium oxide matrix Method for direct determination of Be Cu and Zn.Optimization studies and matrix effects described the uranium separated by chomatography. Trace level impurities were determined using a horizontally viewed ICP 9312737 9313089 9313337 !$ample dissolved in HN03 or HN03-HC104-HF and the relative proportions of tetraethyllead and tetramethyl- lead in the gasoline samples. A more conventional approach for the determination of individual alkyllead species in a gasoline sample is to use some form of chromatographic separation prior to measure- ment of lead using atomic spectrometry. This can be readily achieved by interfacing a packed column GC to a FAAS instrument through a heated transfer line (93/1933). In the latter paper absolute LODs were reported in the range 0.1-0.25 ng with precision of typically 2-6% relative.However sub-pg LODs have been achieved by coupling a capillary GC to an ICP-MS instrument (9312092). In both cases the interfaces could be easily removed allowing independent operation of the instruments. There is growing concern about the adverse effect on health arising from organically bound lead compounds in the environment. Potentially the largest contribution of these species may be derived from alkyllead compounds used in gasoline additives. Although the GC techniques described above can be used for speciation of alkyllead compounds in environmental samples (e.g. water soil) lengthy complexation and alkylation procedures are re- quired to increase the volatility of the trialkyl and dialkyl degradation products of the tetra-alkyl compounds.An alternative approach involving coupled HPLC-ICP-MS has been described (92/4573). It was reported that the determi- nation of inorganic Pb triethyllead chloride triphenyllead chloride and tetraethyllead could be achieved in a single run without the need for time-consuming pre-treatment and/or preconcentration procedures. Limits of detection were quoted as 0.37 0.14 0.17 and 3.9 ng of Pb for the compounds mentioned above respectively. 2.1.2. Lubricating oils The period under review has to a large extent been one of consolidation as far as developments in the detection of trace elements in lubricating oils are concerned with much of the work previously discussed in conference presenta- tions reaching publication. For example a method for the determination of Ba in lubricating oils by AAS using a dinitrogen oxide flame has now been published (9315 14 see also J.Anal. At. Spectrom. 1992,7 349R). The procedure which utilizes sodium dodecane sulfonate and benzyltrime- thylammonium chloride as enhancing agents gave good agreement with standard methods using dinitrogen oxide- acetylene flames (e.g. IP308) and might be particularly useful for smaller blending plants perhaps in remote locations. Similarly Jansen et al. (9214606) have now published their work on matrix eflects in the analysis of lubricating oils using ICP-AES. It was demonstrated that oil additives particularly viscosity index improvers can have a large effect on nebulizer efficiency and hence analytical results. However it was shown that these effects could largely be eliminated by diluting the sample sufficiently and by utilizing an internal standard.It is to be hoped that growing recognition of the importance of these effects will lead to a tightening of standard methods for analysis of lubricating oils by ICP-AES (e.g. ASTM D5 185-9 1 ) which currently do not specify some of the key analytical para- meters. It was also shown that ICP-AES could tolerate wear particles up to 10 pm in diameter. While most wear processes generate particles that are well within this range more unusual cases involving severe wear can generate particles significantly larger than can be efficiently intro- duced to and atomized in an ICP or flame. A rapid method has been described for the determination of wear metals in marine lubricating oils (93/407).These oils are especially prone to particulate precipitation during sample prepara- tion. The procedure involved the use of mineral acid to dissolve the metal particles and a mixture of IBMK and non-ionic surfactant to form stable solutions with the oil samples. Spark emission spectrometry is generally more capable of detecting larger wear particles than ICP-AES or AAS but requires careful optimization of electrode geomet- ries and ashing of the sample on the electrode prior to analysis (see for example 9311 185). Kauffrnan (9312686) demonstrated the detection of metal particles greater than 45 pm in diameter using a rotating disk electrode emission spectrometer. Samples were ashed on the electrode for 30 s at 400 "C prior to insertion into the spectrometer.The analysis of waste lubricating oils for recycling or disposal is an area of growing importance. Since waste oils can become contaminated with environmentally hazardous compounds arising from almost any conceivable source rapid screening techniques are required that cover as many of these potential contaminants as possible. In view of its inherent high sensitivity and rapid multi-element capabil- ity ICP-MS lends itself well to rapid screening of waste oils for heavy metals. Williams (93/2334) has described the use of this technique for the determination of Ag Ba Cd Cr Hg Pb and Se in waste lubricating oils after dilution with organic solvent. Limits of detection for high mass (>80 u)JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 355R elements were between 5 and 50 pg m-3 but those for lighter elements were degraded by isobaric or polyatomic interferences. Some of the most likely hazardous contami- nants in used oils are polychlorinated biphenyls (PCBs) originating from transformer oils. Usually these com- pounds if present are determined using GC with either ECD or MS. However sample preparation techniques for these methods are very time-consuming and so they are not well suited to the rapid screening of very large numbers of samples. A technique has been described which utilizes ETV-ICP-MS for rapid screening of oils for potential PCB contamination (931C367). In this approach temperature programming of the ETV allowed distinction between ‘organic’ and ‘inorganic’ C1. Only those samples which showed ‘organic’ C1 above a specified threshold were then submitted for full GC-ECD or GC-MS analysis.2.2 Organic Chemicals and Solvents This section of the review covers the analysis of organic chemicals reagents and solvents and the format is essen- tially the same as that of previous years (see J. Anal. At. Spectrom. 1992 7 349R). A summary of work concerned with the analysis of organic compounds and solvents carried out during the period under review is provided in Table 2. A comprehensive review (279 refs.) covering the applications of AAS for quality control in the chemicals industry has been published by Ebdon and Fisher (931633). The paper covered a wide variety of industrial applications and placed special emphasis on methods for sample decomposition and reduction of matrix effects.2.2.1 Chemicals As noted in last year’s ASU by far the most active area of research in the analysis of organic compounds at the present time is concerned with elemental speciation. Most of the applications reported involved the coupling of chromato- graphy with atomic spectrometric techniques. A review (68 refs.) has been published covering the use of GC and HPLC with AAS AFS AES and ICP-MS (9214590). Capillary GC is the most commonly applied chromatographic technique largely as the result of the increasing availability of commercial dedicated GC-MIP-AES instrumentation. Ap- plications of the technique in pesticide residue studies environmental surveying drug development and flavour research have been reviewed by Sullivan (9214527).There is however a growing realization that although very powerful the technique has limited scope in application to the elucidation of structural information. The technique can be used to provide element specific and empirical formula data to aid the interpretation of spectra produced by GC-MS and GC-IR systems (931C1489 931C3029 9313309). The application of GC-MIP-AES in this way for the identification of unknown compounds requires that elemental response factors (ERFs) are independent of chemical structure. Work carried out on the variability of response factors with chemical structure previously re- ported in a conference presentation has now been published (931207 1 see also J. Anal. At. Spectrom. 1992 7 349R). A series of halogenated and oxygenated heterocyclic aromatic and aliphatic compounds were studied and it was found that the variation in ERFs for C C1 F N and 0 were less than 3 6 5 6 and 5% RSD respectively for all of the compounds tested.Use of compound independent calibra- tions is thus possible if this level of error can be tolerated. However recoveries as low as 73% for organophosphorus determinations have been reported (931C199). Many of the problems encountered in GC-MIP-AES have been attributed to the capillary discharge tube em- ployed in commercial systems (e.g. wall reactions). Uden and co-workers (931604) have described an alternative concentric dual flow torch which may overcome some of these difficulties. Features of the device included the ability to provide splitless injection of up to 1 pl of sample without extinguishing the plasma a wide range of plasma operating conditions simplified background spectra and improved spatial stability.Another alternative that has been suggested is the use of a novel gas sampling GD source with GC-AES (931C1475). The source was used for the determination of C C1 F and S at pg s-* levels and might well prove useful for stand alone analysis of gases or ambient air in addition to providing element specific detection for GC. Develop- ments in optical systems for plasma emission detection for capillary GC have been reviewed by Camman et al. (931605). Improvements in the design of a monochromator for selective detection were discussed. A system was also described based on oscillating interference filters . Detec- tion limits were reported to be between 140 and 350 pg and dynamic ranges covered four orders of magnitude for Br C C1 and H.Although exhibiting many advantages over traditional ‘selective’ GC detectors MIP-AES lacks adequate sensitiv- ity for many applications and can be limited by reactions with discharge tube walls which necessitate the addition of different reagent gases. Sensitivity can be improved by as much as two orders of magnitude (typically sub-pg s-l LODs) by coupling capillary GC to ICP-MS (931C13 931C85 9312092). This approach has been applied to the determination of organometallic compounds and alkylhal- ides having Kovat’s retention index of up to 3422 (931C85). A system has been described which allows operation of an ICP-MS instrument with either packed column GC or solution nebulization by switching a T-valve and introduc- ing sheathing gas to the torch injector (9312066).The instrument was applied to separation and determination of dichloromethane 1 1,l -trichloroethane and trichloroethy- lene and gave detection limits of 2.6 2.2 and 2.6 ng respectively. Some degradation of solution LODs was noted however. Elemental speciation is particularly important for envi- ronmental contaminants such as organotin compounds where toxicity has been shown to vary greatly depending on chemical form. These compounds are generally insuffici- ently volatile for direct analysis using GC techniques and time consuming derivatization procedures have to be employed. Alternatively HPLC can be used in conjunction with ICP-AES or ICP-MS detection (931C340 931C 1627).However problems can arise if volatile solvents are employed. For example elemental response is affected by the change in solvent composition during gradient elution and LODs can be limited by blank levels and low or variable transport efficiency in the sample introduction system. Vela and Caruso (9312067) have demonstrated the advantages of combining ICP-MS with capillary SFC rather than HPLC for the determination of tri- and tetra-organotin Sn compounds which are amongst the most toxic forms. Detection limits were reported for tetrabutyltin tributyltin chloride triphenyltin chloride and tetraphenyltin of 0.26 0.80 0.57 and 0.20 pg respectively. Relative standard deviations were in the range 1.3-3.4% for five replicate 50 pl injections containing 0.5 ng of Sn.Supercritical fluid chromatography was also combined with a helium MIP-MS instrument and applied to the determination of halogenated compounds including pesticide mixtures (9312070). Abso- lute LODs were obtained for C1 and Br of 15 and 0.75 pg respectively. The linear dynamic range of the technique was established as about 3 orders of magnitude (up to about 50 ng). As mentioned in last year’s ASU (J. Anal. At. Spectrom. 1992 7 349R) SFC has also been used with MIP-AES but selectivity and hence LOD was found to be limited by spectral band interference particularly in356R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 the UV-VIS region (931C1488). An attempt has been made to overcome this problem by use of a high-resolution Cchelle spectrometer for detection of AE from the helium MIP.In addition to their use in chromatography supercritical fluids are increasingly being utilized in sample extraction procedures. The combination of supercritical fluid extrac- tion with ICP-MS has been shown to provide a highly sensitive and selective method for the determination of organometallics (931C1533). It was found possible to make use of the multi-element capability of ICP-MS to derive information about several metal-containing species simul- taneously co-extracted. However as with all extraction procedures the efficiency of partition must be established for quantitative work. The use of supercritical carbon dioxide as a carrier for sample introduction in AAS has also been demonstrated (931439).The study of sensitivity enhancement effects in AAS caused by organic reagents has been an active area of research in recent years (see J. Anal. At. Spectrom. 1992,7 368R). However only two primary papers concerning this topic have been published during the current review period (921582 92/46 14). A comprehensive review (99 refs.) has been published detailing the beneficial effects of organic reagents for sensitivity enhancement and reduction of matrix interferences in both FAAS and ETAAS (931640). The role of trace elements in pharmaceutical formulations is now at last being recognized by the industry and methods for their direct determination have been reported (931530 931 1 155). The use of atomic spectrometry for monitoring the activity of drugs in patients has also been discussed (93/C192).A paper providing advice on the determination of A1 in pharmaceuticals at ultra-trace levels may be of more general interest (9313156). It has been widely recog- nized that this type of determination is plagued by contamination problems. However the role of alumimium in Alzheimer’s disease is presently a topic of controversy within the pharmaceutical industry and a realistic assess- ment of the analytical problems involved in these measure- ments is to be welcomed. An indirect method for the determination of trace levels of the anaesthetics lidocaine dicaine and procaine has been published (93/512). The method involved the formation of a complex with zinc thiocyanide which was then extracted into dichloroethane. Zinc was determined in the organic phase by AAS and the concentration was related to the content of anaesthetic complexed.Applications of atomic spectrometry to the analysis of pharmaceutical packaging materials were also reported. Energy dispersive XRF was used to control the wall thickness of microcapsules for surfur containing drugs (93/2822). An ICP-AES method for the determination of the amount of an iron oxide based ink transferred to a pharmaceutical tablet during the manufacturing process was also discussed (93K1439). 2.2.2 Solvents Several papers have been published during the period under review concerning the effect of organic solvents on atomic spectrometric techniques including AAS AES AFS and MS. For techniques utilizing an ICP source the effect is generally detrimental particularly in ICP-MS where mole- cular ion interferences originating from the solvent can be significant.It has been shown that optimization of instru- mental parameters can result in some reduction in these matrix effects (931C60). However it is usually better to reduce the amount of solvent actually reaching the plasma. Hill et al. (9312056) have described a novel approach for the analysis of volatile solvents using ICP-MS in which small volumes of sample were injected into a carrier stream of dilute nitric acid (2%) using an FI valve. The plasma remained stable throughout if sample injection volumes were minimized allowing LODs in the ppb range to be achieved. However when a membrane drier tube was incorporated into the system to improve desolvation LODs were further reduced to sub-ppb levels.A membranephase separator was also used to separate organic and aqueous phases for FI on-line solvent extraction in FAAS (931C3059). In this approach Cu in water samples was determined with enhancement factors of 10 and 16 and sampling frequencies of 80 and 180 per hour by extraction into bromoxine and 1 4 toluene xylene respectively. Organic solvents can also have a detrimental effect on the performance of ICP-AES owing to such problems as thermal quenching of the plasma build-up of carbon on the torch and spectral band interference from molecules such as C2 and CN. A new direct serial coupled r.f. generator has been developed which was found to reduce quenching effects thus allowing improved stability when introducing volatile solvents (931C288).However molecular band interferences could still be present. Tang et al. (931508 9313163) described the use of a cooling gas consisting of 50% air and argon running on a commercially available 40.68 MHz ICP. Compared with the pure argon ICP the air-argon plasma offered several advantages for the analy- sis of organic solvents by AES. These included the avoid- ance of carbon build-up on the torch injector the reduction or elimination of molecular band interferences and for many analytical lines lower LODs. Unlike AES the introduction of organic solvents can have a beneficial effect when the ICP is used for AF measurements (931689). It was shown that organic solvents with moderate volatility and viscosity could effectively increase the fluorescence intensity of many elements.A similar effect is observed when organic gases such as propane are introduced into the plasma. Long and Bolton (93/2083) have carried out a series of experiments using AES and AAS to try to elucidate the mechanism. For AAS refractory elements were found to exhibit enhancements due to the role of elemental carbon (originating from the propane or the solvent) in assisting the dissociation of metal oxides in the plasma. However in AES this phenomenon was compromised by the reduction in the effective plasma power which accompanied introduction of the propane or solvent leading to a reduction in sensitivity for elements with high transition energies. For AFS measurement in flames the situation can be more complex with some solvents producing enhancement effects and others suppres- sions.Anwar et al. (93/3317) have studied the effect of organic solvents and acids on the laser-induced AF of Sn in air-hydrogen flames and concluded that analyte atomiza- tion was a direct function of the concentration of free hydrogen atoms present. 2.2.3. Catalysts There are many analytical methods available in the litera- ture for bulk elemental analysis of most common catalysts and support materials used in industrial chemical pro- cesses and these have been summarized in previous ASU reviews (see also Table 2). However in order to understand catalyst activity it is necessary to know not only the bulk elemental concentrations but also how the active compo- nents are distributed at the surface of the catalyst.Secon- dary ion mass spectrometry is perhaps one of the most powerful approaches available for this type of analysis. The application of SIMS to the characterization of heterogene- ous catalysts has been described in a comprehensive review (9312646). Specific investigations reported during the per- iod under review have included the characterization of the surface structure of supported catalysts using static and dynamic SIMS. In the former application the concentra- tion of the active component (molybdenum trioxide) on theJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 357R surface of the novel catalyst (molybdenum trioxide-cobalt oxidehitanium dioxide-alumina) was measured using SIMS and found to be correlated with the hydrodesulfuriza- tion reactivity of thiophene at atmospheric pressure (93/2603).In the latter study SIMS was used to check for potential migration of Cs from the surface of an alumina- based silver catalyst during high-temperature treatment (9312452). A combination of SIMS and X-ray Photon Spectroscopy (XPS) has been used to study the surface chemistry of commercially available activated carbons commonly used as catalyst supports (931242 1 ). Surface impurities were monitored after different chemical pre-treatments and were found to provide information which led to a better understanding of factors influencing precious metal disper- sion and catalyst activity in powder and shell type catalysts. These techniques have also been combined with sputtered neutral mass spectrometry (SNMS) to study the transforma- tion of amorphous glassy metal-zirconium alloys into carbon dioxide hydrogenation (dispersed metal on zirconia) catalysts (9312993).It was reported that studies with model substrates with defined layer structures indicated that the interpretation of depth profiles (e.g. ZrOJZr interfaces) was most straightforward using the SNMS data. It was found that not all metals were equally activated under pre- treatment conditions. Borg et al. (93/245 1) have studied the surface chemistry during preparation of an Rh-alumina catalyst. The model catalyst consisted of a flat electrically conducting support comprising a thin film of alumina on an aluminium foil onto which Rh was deposited from a solution of rhodium trichloride.The flat conducting nature of the support allowed the study of the catalyst surface using SIMS high resolution and angle dependent XPS and Rutherford backscattering. Information was thus obtained about the effective layer thickness of Rh and the extent to which the support was covered. Although in many cases the application of surface analysis techniques is necessary in order to elucidate the form of active metals on catalyst supports it is possible to obtain such information by careful application of classical chemical techniques. Monque et al. (93/3338) have used this type of approach in the determination of intra- and extra-framework Ga species in zeolite structures. The method employed relied on the fact that whereas treatment with hydrofluoric acid dissolved all of the gallium in the sample a controlled digestion with hydrochloric acid allowed the determination of only non-framework species.The zeolite structure was left intact by the latter procedure. Over the years extensive work has been carried out on the measurement of combustion product emissions from auto- mobiles and this has lead to the increasingly widespread utilization of exhaust catalysts in order to reduce these emissions. It is therefore interesting to note the appearance in the literature of methods for the determination of platinum emissions from catalyst equipped gasoline engines (9313 177). Particle samples were collected from the exhaust pipe of an automobile engine equipped with a 3-way cata- lytic converter and digested in 30% nitric acid for analysis by ETAAS.Volatile samples were collected in a series of impingers and absorption tubes. The emission concentra- tions of Pt under different loads ranged from 3 to 40 ng m-3. 2.3 Inorganic Chemicals and Acids Despite the growth in ICP-AES and more recently ICP-MS usage for the analysis of inorganic chemicals flame atomic absorption Spectrometry still accounts for a significant proportion of the abstracts received in this category. Although this perhaps reflects the economics of the situa- tion rather than the merits of the techniques in question it also demonstrates that with inventive front-end chemistry for separation and preconcentration FAAS can be employed for trace level analysis in a variety of complex matrices. Thus FAAS was used for the determination of trace levels of Pb (pg g-l) in salt and water samples after a preconcen- tration procedure on xanthate cotton (931654).In a related report Cu was also determined in the same matrix (93/654). Other applications involving FAAS included a description of extraction systems for the determination of A1 and A1 salts (92/4323); the indirect determination of nitro compounds (931685); and the detection of trace elements in strontium preparations (93/1111). The determination of trace elements in solutions contain- ing high amounts of dissolved salts is a recurring theme in this section of the review and reflects the considerable amount of effort expended on this difficult area of analysis. Difficulties with sample introduction and chemical physi- cal and spectral interferences are commonly encountered in such applications.It is not surprising therefore that in the majority of the applications reported some form of sample separation/preconcentration procedure was employed. A simultaneous solvent extraction procedure was reported for the determination of a suite of elements in brine water by FAAS (931658). The samples were buffered by NaOAc to pH 5.7. The metals were extracted into an organic phase consisting of DDDC-IBMK. The ratio of sample to organic was 1O:l and 100% recoveries were obtained for all elements studied. Cadmium has been determined in a sodium chloride matrix by FAAS using a coprecipitation method (92/4538). The metal was coprecipitated with magnesium hydroxide and dissolved in hydrochloric acid.Ammonium chloride and sodium hydroxide were added and Cd was extracted with sodium diethyldithiocarbamate (92/4538). Ultrasonic sample pre-treatment was used in the analysis of brine and common salt for Zn by FAAS (93/3296). This was claimed to result in the decomposition of Zn-organic compounds increasing sensitivity speed and reproducibility of the analysis. A method for the determination of total iodide in brines and sea-water by atmospheric pressure helium microwave plasma AES may also be of interest (93/2122). Work continues to be reported on the application of a high-pressure nebulizer system to the analysis of solutions containing high levels of dissolved solids (92x42 16 93/1082). In this system the liquid sample was forced through a special nozzle at high pressures (5-40 MPa).The liquid impacted upon a platinum-iridium plate with an orifice of 10-30 pm and the resulting constant flow (1-5 ml min-') of liquid through the orifice produced a fine mist. This system was compared with conventional pneumatic nebulization for the analysis of a variety of sample types of varying viscosity. As a result of the improved aerosol yield the high pressure nebulizer system provided an improve- ment in sensitivity of 2-3-fold on the basis of peak height and 6-8-fold on the basis of peak area measurements. Highly concentrated and viscous solutions which proved problematic or impossible with conventional nebulization could be introduced into the flame without difficulty with the high pressure system. Flow injection has been coupled with ICP-AES for the simultaneous multi-element analysis of sodium chloride (931496).Sample dispersion was mini- mized by the use of a mini-cyclone spray chamber. Matrix effects on the determination of 11 trace elements were discussed. Results obtained indicated that the use of FI reduced analytical signal drift and provided better signal reproducibility. A tungsten spiral electrothermal atomizer has been em- ployed for sample introduction into a d.c. arc for the determination of trace levels of Cu in pure sodium chloride (931703). Factors such as carrier gas flow rate current intensity vaporization temperature and the concentration of sodium chloride were studied. The technique was used358R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 for the determination of Cu in sodium chloride reagent and results obtained gave good agreement with those obtained using ICP-AES. Inductively coupled plasma atomic emission spectrometry continues to be heavily utilized for the analysis of inorganic chemicals. A method for the determination of REEs in phosphate samples has been reported (93/757). In this method complete dissolution of the sample was achieved using a multi-part acid digestion (a) dissolution with hydrofluoric-nitric-hydrochloric acids in a PTFE closed beaker and subsequent treatment with perchloric acid; (b) treatment with the same procedure as described in ( a ) but with fuming hydrochloric acid replacing perchloric acid; (c) application of nitric acid and fuming hydrochloric acid in a quartz vessel; and ( d ) final treatment with a hydrofluoric- perchloric-nitric acid mixture.High-purity phosphorous trichloride was analysed by ICP-AES combined with the use of an electrothermal atomizer for analyte preconcentration and sample introduction (931779). Details of other applica- tions involving ICP-AES are given in the tables. The increased requirements for the strict quality control of high-purity chemicals and reagents place considerable demands on the performance required by modern instru- mental analytical techniques. In semiconductor fabrication current acceptable levels for certain metal and non-metal contaminants are in the pg g-* range and by 1997 high- purity acids required for the manufacture of semiconductor devices with 0.25 pm geometries are expected to require impurity levels not exceeding 0.1 ppb. A comparison of direct analysis dilution and preconcentration sample pre- paration for ICP-AES ICP-MS and ETAAS for the ultra- trace analysis of high-purity acids has recently been presented (93/C2 15).Data on spectral interferences sample handling procedures and instrument parameters were dis- cussed. The performance of ICP-MS for the analysis of semicon- ductor-grade reagents has been reviewed (93122 1 7). The performance and limitations of quadrupole based instru- ments were explained and alternative sample introduction techniques including a novel nebulization system were highlighted. The advantages of magnetic sector based ICP- MS systems were outlined and a review of current and future levels of performance expected from a commercially available high resolution ICP-MS instrument discussed.A review on the quality control of high purity process chemicals using ICP-MS has also been reported (93/2486). A review (13 refs.) comparing ICP-AES and ICP-MS has also been published (93/2988). The main features and limitations of each technique are highlighted. The analysis of small volumes of hydrofluoric acid samples by direct injection nebulization ICP-AES has been reported (93/C 1420). A direct injection nebulizer constructed from materials resistant to hydrofluoric acid allowed multi- element determinations to be performed using less than 100 pl of sample. Steady-state signals were achieved with less than 20 pl of solution. Detection limits precision data and the effect of the concentration of hydrofluoric acid were discussed.Finally the application of tunable diode lasers to the control of high-purity material technologies has been described (9314475). The spectrometer employed a heated evacuated system for gas inputs and the use of the system for the analysis of water content of oxygen argon and germanium hydride was reported. Electrothermal AAS has been employed in a number of applications relating to the analysis of silver nitrate used in the photographic industry (921434 1 931690 93/7 16 9311143). Other applications reported for the analysis of inorganic chemicals by ETAAS included the determination of nanogram amounts of heavy metals in highly pure barium nitrate (931652); the determination of Mn Pb and Cd in zinc sulfate (9313272); and trace impurities in high- purity bismuth oxide and zinc oxide (9311 13 1).Electrother- mal AAS has also been applied to the analysis of environ- mental samples. The use of an alternative mercury-palla- dium chemical modifier for the determination of Se in coal fly ash has been reported (9312134). The modifier which contained equal amounts of mercury and palladium was added to the sample at a concentration of up to 0.1%. After digestion Se was determined either by the method of standard additions or by reference to aqueous standards containing the modifier. Good agreement was obtained with a certified coal ash reference material using this procedure. A slurry sample introduction procedure for the determination of elements of varying volatilities in coal coke ash and sludge samples by ETAAS has been described (93lC1366).The slurries were prepared by ultrasonic homogenization of the powdered sample in a solution containing 5% HN03 and 0.1% Triton X-100. Standard furnace programmes were employed and the results ob- tained showed good agreement with those obtained using conventional dissolution techniques. The precision ob- tained between slurries containing differing masses of sample were typically 10% and compared favourably with those shown between various sample decomposition proce- dures. Direct solids analysis using a low pressure electrother- mal atomizer for the determination of Ag and Cd in fly ash samples has been described (931C374). The analytical sensitivity could be controlled by varying the pressure of nitrogen in the atomizer.This could be used to analyse relatively high sample masses (3 mg). The precision of the determination was claimed to be of the order of 10% . The atomic profiles generated were used to study the form and location of the trace elements in the fly ash samples. Results obtained suggested that Ag and Cd were located on the surface of the fly ash and were not incorporated in the aluminium silicate matrix. It was suggested that in addition to providing quantitative results with high sensitivities and a large dynamic range this approach might be useful in determining the location of the analyte elements without the need to resort to more expensive and time-consuming traditional surface techniques X-ray fluorescence spectrometry continues to enjoy wide- spread use in the analysis of inorganic chemicals and related products.High-density brines are used to control high pressures during oil and gas well operations. These dense brines are solutions prepared from salts such as calcium chloride calcium bromide zinc bromide and/or combinations of these. During stages of completion exces- sive losses of these expensive brines to the production zone can occur. Before the brine can be re-used the composition of the brine needs to be re-formulated. A determination of the composition of the brine must therefore be undertaken so that the correct amount of salt is added to the depleted stock. The Compton scatter ratio method has been em- ployed for the correction of matrix interferences in the analysis of high-density brines (93/2008). This technique is advantageous in samples having a low atomic number in which the scattered intensity is high.A procedure using this technique for the determination of Ca C1 and Zn in brines was described. A method for the rapid characterization of coal fly ash has been outlined (93128 19). The optimization of the sample preparation technique has been described in detail. The data obtained compared well with wet chemical analysis. In a similar application the feasibility of different X-ray techniques have been examined for the analysis of fly ash samples as bulk or as individual particles (9312746). The measurement of low atomic number elements by TXRF in sodium bicarbonate has been reported (93/1879). The advantage of employing the total reflectance technique was that good SBRs and LODs could be achieved (ng g-') by virtue of the significant reduction of background scatter.An XRF system has been described for the study of theJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993. VOL. 8 359R composition of protective coatings (93/4462). This system was designed for the non-destructive analysis of thin multicomponent layers on substrates of large dimensions. The instrument was based on an energy dispersive spectro- meter and could be used for the simultaneous determina- tion of elements ranging from atomic number 20-92. The system was applied to the determination of the composition of protective layers on the surface of Ti anodes used for the production of chlorine. 2.4.Nuclear Materials Inductively coupled plasma mass spectrometry has now achieved almost universal acceptance as a powerful tech- nique for the analysis of nuclear and related materials. The high sensitivity multi-element capability speed of analysis and the ability to provide isotopic as well as elemental information combine to make this technique almost indis- pensable to the nuclear industry. The rapid growth of this technique in recent years has been reflected in the increas- ing number of abstracts received describing applications of ICP-MS in this field. The use of ICP-MS in an impurity assay of reprocessing uranyl nitrate has been reported (93/C 13 10). The benefit derived from the use of ICP-MS is that direct analysis is possible without the need for time- consuming solvent extraction steps normally required for analysis using either AAS or ICP-AES.The determination of trace metals in uranium oxide using ICP-MS with an on- line solvent extraction procedure has been described (92/4575). An aqueous solution containing uranium (2% m/v in 1 mol 1-' nitric acid) and triocylphosphine oxide in cyclohexane were pumped alternately through a PTFE tube where they were allowed to mix thoroughly. The organic phase containing the uranium was removed on-line by allowing the solution to pass through a microporous PTFE tube which owing to its hydrophobic nature allowed the organic phase to selectively permeate through its walls. This technique allowed determination of trace elements in uranium in the range 1-45 ppb. A procedure for the determination of traces of 237Np in isotopically enriched solutions of uranium has been outlined (93/2060).Neptu- nium-237 was extracted from 1 moll-' nitric acid using 0.5 mol 1-I thenoyltrifluoroacetone leaving 99% of the ura- nium matrix in the aqueous phase. The Np was re-extracted in 10 mol 1-I nitric acid and the resulting solution was heated to remove the acid. The instrumental parameters were optimized to suppress the spectral overlap between 237Np and uranium-238 from the matrix. The suppression of the analyte signal arising from high concentrations of uranium was corrected by the use of an internal standard. The analytical performance achieved was comparable to that obtained using alpha spectrometry. However the latter requires a tedious pre-treatment and measurement process.The ICP-MS technique has also been applied to the determination of Tc (93/2244). Spectral features and analytical figures of merit were described. A specially designed glove box containing ICP-MS instrument was used. A commercially available ion chromatography system incorporating an iminodiacetate functionalized chelating resin has been used for preconcentrating U prior to determination by ICP-MS (93/C292). The U was concen- trated on the resin using 1 moll-' ammonium acetate at pH 5.5 while the majority of the sample matrix not retained on the resin was passed to waste. Uranium was subsequently eluted from the resin by the addition of 1.25 mol 1-I nitric acid. Use of this matrix elimination procedure is claimed to allow determination of U in complex matrices at the ppt level.The optimization of the separation system was described and its application to a number of complex matrices outlined. The LODs linear range accuracy and precision were assessed using both a standard Meinhard concentric nebulizer and a CETAC ultrasonic nebulizer. The detection of actinides at the sub-ng 1-* level in industrial waste waters by ICP-MS has been described (93129 15). Conventional pneumatic nebulization and ultra- sonic nebulisation were compared. The direct analysis of solid samples by ICP-MS using LA sample introduction has also received attention. The semiquantitative determination of 23 impurity elements in a uranium oxide CRM has been reported (93/1003). Matrix-matched single point calibration was achieved by using another CRM from the same series of standards.Reproducibility was poorer when no internal standard was employed or when replicate ablations of the same area of the target were performed. The analysis of spent nuclear fuel is carried out normally after dissolution in 7 mol 1 - I nitric acid which precludes the analysis of fission gases (Kr Xe I) which are lost. Other fission products form insoluble residues which makes the complete characterization of the spent fuel difficult. In addition all spatial information is lost when dissolving the sample. Solid sampling techniques currently applied to spent fuels include mainly EPMA and gamma spectroscopy. This approach is limited as EPMA does not provide isotopic information and gamma spectroscopy may be limited to only a few isotopes.Laser ablation ICP-MS has been applied to the direct analysis of spent solid nuclear fuels (93/C13 11). The fuel samples were cut embedded in araldite and polished. The whole pellet including the cladding was analysed by LA-ICP-MS. This technique has also been applied to the direct determination of the isotopic abundance of U (93/C 1326). Samples were deposited onto cellulose filters as either solid or liquid samples. Results were presented for the analysis of a number of SRMs. Other applications of atomic spectrometric techniques to the analysis of nuclear materials are summarized in Table 2. 2.5. Process Analysis and Automation The number of abstracts received on process analysis and automation do not truly reflect the amount of activity in this field as the vast majority of applications are imple- mented in industrial settings and are not reported in the literature.Thus this section of the review cannot hope to give a comprehensive overview of activity in this important area but can only give a flavour of the sort of problems that are currently being addressed. Despite advances in instrumentation which have revolu- tionized the way analysis is carried out in the modem laboratory the expertise and acquired knowledge of the analytical chemist still remains outside of the instrument cabinet. As more and more of this knowledge is lost in rapidly changing labour markets there is a clear need to develop analytical instrumentation that will provide some degree of informed decision making capability.This may range from technique advisors providing some diagnostics on data or methodology to self-optimizing instruments or to the use of chemometric techniques to provide more sophisticated treatment of results. In the past few years applications of artijicial intelligence techniques to atomic spectrometry have begun to appear in the literature. The impact of this type of approach may change radically the way instrumental analytical chemistry is perceived. An intelligent system for the automation of quality assurance and control procedures in ETAAS has been reported (93/C1576).The system was developed to automate the US EPA contract laboratory programme for the analysis of waste waters. A control system for use with a high- resolution ICP has also been developed to comply with this programme (931C289).Application of the system was demonstrated for the determination of target elements in360R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 waste waters. An expert system for the interpretation of semiquantitative ICP-MS data has also been reported (93/C1596) as has an expert system for diagnosis of problem AAS data (931806). The combination of XRF with multivariate pattern recognition has been employed for metals screening and pre-processing decisions in respect of hazardous waste operations (93K257). X-ray intensities rather than quanti- tative data were used to generate patterns of specific generators based on quantitative spectral features. The performance of neural network models for calibration data in XRF spectrometry have been studied.Two training models were evaluated namely backward error propaga- tion and a genetic algorithm (92/47 10). An overview on the general usefulness and the theory of fuzzy sets for solving problems in the field of data analysis and analytical reasoning as well as for using neural networks for knowl- edge processing in analytical chemistry has been published (93/18 17). Recent progress in the development of intelli- gent systems for automated qualitative analysis in XRF and in ICP-AES were discussed. A review (32 refs) of on-line particle composition determi- nation has been published (9311 864). An article describing automated element analysis for control of the cement manufacturing process has been also been published (9311844).Finally a robotic system for the automated preparation of environmental samples for analysis by ICP- AES has been described (9313327). The system was de- signed for the preparation of several types of sample of increasing relevance to industrial plant operations rivers and well waters; surface waters and effluents; and soils sludges and sediments. 3. ADVANCED Developments in technique and methodology for the analysis of advanced materials are outlined in this section of the review. Key areas in which progress has been reported in the past year are highlighted in the text. A summary of reported analytical methods of relevance to the analysis of advanced materials is provided in Table 3. 3.1. Polymeric Materials and Composites X-ray fluorescence spectrometry is widely used in the plastics industry because the technique is able to provide a means of rapid non-destructive analysis with a minimum of sample preparation.Warren (93/284 1) has compared XRF with other non-destructive techniques such as neutron absorption and scattering gamma ray absorption and ultrasonic methods for the determination of fibre and mineral content in engineering plastics and composites. The applications described concerned the estimation of major components in materials formulations and com- ments were made regarding the feasibility of use for operation in a production environment. On-line applica- tions of XRF in polymer blending have been briefly described in a wider review of the subject (93/1803). A method has been described for the direct determination of S in co-polymer powders by energy dispersive XRF (92/4459).As with any technique for the direct analysis of solids the provision of appropriate calibration standards is required to achieve optimal accuracy. Strategies for the use of calibration standards in XRF have been outlined for a range of materials including synthetic plastics (93/ 1732). However it is not always possible to obtain an adequate range of plastic materials suitable for calibration purposes. The organizations which produce certified standards do not offer polymers as major matrix components. It is possible to use samples previously analysed (e.g. by ICP-AES) as standards for XRF calibration but the concentration range obtainable is normally restricted to production formula- tions.However XRF can still be used directly in conjunc- tion with a chemical sample preparation step. Thus a method has been proposed for the simultaneous determina- tion of heavy metals in plastics using fusion of the sample with sodium hydroxide in the presence of sodium nitrate as an auxiliary oxidant (93/1802). Sodium diethyldithiocar- bamate and sodium rhodizonate were used to precipitate As Ba Cd Cr Hg Pb and Sb which were then detected by XRF. This method was shown to be rapid and to give results that were comparable to those obtained for the recommended decomposition procedures for individual elements. MATERIALS Sample preparation was also the main area of attention in the application of AAS to the analysis of plastics in the year under review. The presence of heavy metals residues in plastics is subject to legal restrictions in many countries.The emission of particulates containing toxic metals is an important consideration in the operation of waste incinera- tion plants (92K4212). A study of the volatility of such metals in plastic wastes under conditions of combustion was carried out using cup-in-flame AAS. Samples of paints plastics and plastic additives were placed in a graphite cup and introduced into the flame. The temperature of the cup was increased by the flame by up to 1 100-1200 "C as measured by a thermocouple or pyrometrically . The volatil- ity of the selected metal was recorded as a function of temperature by AAS. The technique was applied to Cd Cu Pb Sn and Zn. A comparison of dissolution procedures based on microwave digestion and oxygen flask combustion has been reported for the determination of Cd and Pb in a range of materials including poIy(viny1 chloride) poly(pro- pylene) polyethylene polystyrene poly(ethy1ene terephtha- late) and polyamide (93/3245).It was found that both methods gave acceptable agreement with a conventional wet ashing procedure and were considered to be time- saving and cost effective pre-treatments for FAAS. The determination of A1 and Ti in poly(propy1ene) by FAAS and ICP-AES has been reported (93/1233). The sample was fused with potassium hydrogensulfate and the melt dis- solved in sulfuric acid prior to analysis. Precision was reported to be of the order of 8% relative for each element using this method. Germanium is widely used as a catalyst in the production of polyesters (93K879).It was reported that both dry and wet ashing using mineral acids offered suitable means of sample preparation for the detection of Ge in polyester by ICP-AES. It was noted that dilute hydrochloric acid (unlike sulfuric or nitric acids) was found to enhance the emission signal for Ge and this was attributed to improved sample transport efficiency arising from the formation of volatile chloride species. An interesting new technique has been proposed for the direct examination of waxes and other low melting-point solids by ICP-AES (93K972). The samples were melted and nebulized in the molten state at elevated temperature. The technique was used to monitor the metal content of waxes during the manufacturing process. Palla- dium has been determined in a polymer matrix by ICP-MS (93lC1348). The sample was decomposed using a sulfuric acid-hydrogen peroxide regime and rhodium added as an internal standard.A detection limit of 5 ng kg-l of Pd in the polymer was reported. Mass spectrometry has also beenJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 361R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS Technique; atomization; Element Matrix analyte form* POLYMERIC MATERIALS AND COMPOSITES- Al Polypropylene AA;F;L Sample treatmentlcornments Fusion with potassium hydrogen sulfate and dissolution of melt in dilute sulfuric acid; A1 detected in the range 2- 125 pg g-' Cd Paper and pulp AA;-;L Cd Plastics AA;L;F Cr Butadiene rubber AA;F;L Fe Leather Mn EPDM rubber Pb Paint Pb Poly(viny1 chloride) Pb Paint Pb Poly(viny1 chloride) Pb Plastics Pd Polymer S Copolymer powders Sn Poly(viny1 chloride) Ti Polypropylene Ti Paints Various (5) Paints and plastic waste Various (7) Polycarbonate Various (3) Paper Various (5) Paper and insulating- Various (7) Plastics grade pulp AA;FL XRF;-;S 1CP;AF;L AA;ETA;S Laser;AE;S AA; ETA$ AA;L;F M S;ICP;L XRF-$3 AA; ETA;L AA;F;L XRF;-;S AA;F;S AA;ETA;S SIMS AA;F;L XRF-;S SEMICONDUCTORS- Ag Cadmium and zinc selenides AA;ETA;L Ag Germanium selenide films SIMS A1 Gallium arsenide-aluminium SIMS gallium arsenide Pressurized digestion of 1 g of sample with concentrated nitric acid in a PTFE crucible; detection limit 10 pg kg-' Comparison of microwave digestion and oxygen flask sample preparation methods with wet ashing for a range of polymers 5 g of sample was heated in a muffle furnace at 600 "C for 1.5 h treated with nitric acid and ashing was completed; the residue was dissolved in 2 ml aqua regia and diluted to 25 ml with water of Fe leached was 0.45 p g ml-I applicable to detection of manganese dioxide additive Dried paint samples were ashed at 475 "C and the residue dissolved in nitric acid; detection limit of the method was 10 ng ml-' and precision was 4% relative Direct sampling using 2-5 mg of solid; detection of Pb in the range 0.2-1% rnlm; linear range 0-40 mg Pb Direct sampling of paint layers in situ; system was miniaturized for field sampling; measurement at 220.35 nm with a detection limit of I % rnlm Pb Direct solid sampling for detection of Pb in the range 0.1-1.0% rnlm; RSDs between 5 and 10% As for Cd.Sample was decomposed using sulfuric acid and hydrogen peroxide; rhodium was used as an internal standard; detection limit of 5 pg kg-I Direct determination by energy dispersive instrument based on intensity of S fluorescence Sample was decomposed with a mixture of sulfuric acid and hydrogen peroxide or dissolved in THF; detection limit of 0.4 pg g-I Sn was reported As for Al; Ti detected in the range 2-25 pg g-I Sample was dried calcined and the ash fused with a borate flux at 1000-1 600 "C for 5-30 min Sample was introduced to the flame in a solid sampling cup for the direct determination of Cd Cu Pb Sn and Zn Direct determination of Cr Co Cu Fe Mn Na and Ni by solid sampling Imaging of distribution of AI Ca and Na on surface of paper Samples were calcined at (600 "C; detection of Cu Fe Mn K and Na Detection of As Ba Cd CrIIl Hg Pb and Sb after destruction of the polymer with sodium hydroxide and sodium nitrate as auxilary oxidant; preconcentration with NaDDC Analysis of aqueous extracts; maximum concentration Sample was ashed and analysed by EDXRF; Treatment with hydrochloric acid at pH 1.2; detection limit for Ag reported as 0.01 pg I-' Depth profiling of isotopic Ag dissolution in vitreous thin films of germanium selenide on silicon Quantitative analysis and characterization of depth distribution in heterojunction Reference 9311233 92/44 5 2 9313245 9312645 9214273 931 1693 9214542 93lC 138 931C1558 9312080 9313245 93lC I348 9214459 931842 9311 233 9312850 9 2 x 4 2 12 931574 931 I207 9311282 931 1802 9 3lC9 3 2 9312366 9311 278362R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 3 Element As As Au B B Be C Cr c u c u Fe Fe Fe Ge Ge H In In In In Mg 0 Sb Si Si Sn Sn SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Technique; atomization; analyte form* XRF-;S Sample treatmentlcomments under As pressure at 470 "C by total reflection detection; sensitivity for As La line was < 1 monolayer Quantification of As in silicon-silicon dioxide interfaces; As was reported to be enriched by a factor of 4000 at the interface deposits on silicon substrates; accuracy and precision of AAS was better for Au determinations; memory effects observed using Investigation of the surface of indiumphosphide Comparison of techniques for detection of alloy ICP-AES Sample was digested and B extracted as tetrafluoroborate ion associated with Ethyl Violet into toluene after adjustment of solution to pH 5; detection limit of 1 ng ml-l B Qunatitative determination of B below I ppm using sample rotation method Determination of dopant Be using sputtered neutrals for quantification Study of effects of latering ion beam parameters on SIMS quantification in single crystals Laser evaporation resonance ionization time-of-flight MS instrument; detection limit of below 1 x lo9 atoms cm-2 claimed and vapour phase decomposition methods for detection of dopant Cu Quantification of Cu segregation under oxygen ion bombardment Comparison of dry ashing and FAAS detection with a solid sampling ETAAS procedure using oxygen ashing Removal of metal contamination on the surface of silicon wafers was studied by TXRF As for Cu Measurement of film thickness on Polikor substrate Determination of Ge content and distribution interface characterization and film thickness measurements were discussed Use of caesium ion bombardment and detection of HCs+ ions for quantification of H content in hydrogenated silicon thin films Layer by layer determination of In by etching of film on gallium arsenide substrate with bromine in hydrobromic acid; detection limit of 1.3 x loi8 atoms ~ m - ~ using Zeeman effect background correct ion Comparison of TXRF backscattering spectroscopy Emission spectographic study of crystal growth Sample was sputtered onto a graphite platform which was then introduced to the ETA; determination of dopant content at about 500 ppm level Direct determination of In in single crystals using K alpha line (Quantitative determination of Mg dopant by detection of caesium cluster ion detection A s for C ,4s for In; detection limit of 1.2 x loi7 atoms ~ 1 1 7 ~ ~ ,4s for In ,4s for Ge ,4s for Au; precision and accuracy for Sn determination similar for both techniques Comparison of methods; ETAAS procedure employed platform atomization with orthophosphoric acid and magnesium nitrate as chemical modifiers; detection limit of 3.4 p g g-l; ICP-MS method limit was 0.5 ng g-l reported Matrix Indium phosphide Reference 931201 2 9 312 5 77 931C 143 5 9214722 9312 5 7 4 93/2465 9312972 931222 1 9312451 9312 52 3 931569 9311752 9312457 93/2033 93125 13 9312525 9214507 921455 1 931 1640 931 272 5 93/22 16 9312912 9214507 921455 1 9312033 93/C 1 43 5 931C 1598 Silicon-silicon dioxide SIMS Silicon AA and AE;F and 1CP:L Silicon and silica Aluminium film on silicon SIMS RIMS SIMS RIMS Gallium arsenide-aluminium Silicon gallium arsenide Silicon wafers Surface analysis Silicon SIMS Silicon Photoresists AA;ETA and F;S and L Silicon wafers XRF;-;S and L Silicon Silicon-germanium films Silicon-germanium structures Surface analysis SIMS XRF-;S Amorphous silicon films SIMS Cadmium telluride films AA;ETA;L Gallium arsenide Cadmium telluride AE;-;- AA;ETA;S Bismuth indium selenide Aluminium gallium arsenide Silicon Cadmium telluride films Gallium arsenide Silicon-germanium films Silicon Indium phosphide XRF;-:S SIMS SIMS AA;ETA;L AE;-;- XRF-;S AA and AE;F and 1CP;L AA or MS;ETA or 1CP:LJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 363R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix Zn Photoresists Various ( 4 ) Semiconductors Various Semiconductors Various ( 3 ) Silicon wafers Various ( I 5 ) High-purity gallium and indium Various (5) Photoresist Various ( 10) Molybdenum disilicide Various Semiconductors Technique; atomization; analyte form* AA;ETA and F;S and L SIMS SIMS MS;GD;S AE;-;S MS;ETV-ICP;L AE;ICP;L AE;HCL;S Various ( 3 ) Tungsten-titanium materials MS;GD;S Various ( 4 ) Silicon wafers Various (10) Silane XRF-:S AE;ICP;G Various ( 8 ) Arsine AE;ICP;G Various ( 9 ) Indium phosphide SIMS Various (27) Semiconductors SIMS Various Silicon Various (70) High-purity gallium AA or XRF; vapour phase decomposition;- MS;GD;S Various ( 3 ) Cadmium mercury telluride AA;ETA;L GLASSES- A1 Glass containers As Glass B Borophosphosilicate glass ETAAS SIMS and XPS AA;H y;G XRF;-;S Sample treatmentlcomments As for Fe Review of quantitative applications of the technique including to the determination of C H 0 and N Capabilities of SIMS instrument operated in secondary neutral analysis mode for more reliable quantification samples; applied to detection of C 0 and P at sub-ppm levels extaction and concentration of analytes on graphite powder collector Sample was diluted 10-fold in ethoxy ethyl acetate and evaporated into the ICP; standard additions were used for the detection of Cu Fe Mn Na and Ni; results were in good agreement with ETAAS Qunatitative coprecipitation of Co Cr Cu Fe Mn Ni Ti V Zn and Zr using lanthanum hydroxide Description of applications of hot hollow cathode discharge to materials including silicon and germanium; detection of impurity elements reported at ppm levels free sample preparation for the determination of Li K and Na at ppb levels surface contaminants including Cu Fe Ni and Zn for determination of Al C Cu Fe Ge Mg Na Sn Ti and Zr for determination of C Fe Ge Mg Mo Ni Sn and V Caesium ion bombardment for detection of negative molecular ions of Al Cu Ge Mg Pb Sb Sn Ti and Zn Fast xenon atom source bombardment for detection of impurities in gallium arsenide germanium and silicon at limits between 1Olo and loL3 atoms cm-$ surface distribution of B and S on silicon wafers also investigated measurement techniques for the determination of trace metals Procedure described for cryocooling liquid gallium to avoid impurity segregation Sample (0.5 g) was dissolved in hdyrochloric-nitric acid mixture and diluted to 25 ml; Ag and Cu were determined using platform atomization; In was determnied using tube wall atomization Direct analysis using sample cell accomodating flat Separation of base material from impurities by Investigation of methods of achieving contamination- Use of total reflection XRF for quantification of Use of sealed plasma for safe containment of sample Use of sealed plasma for safe containment of sample Study of the use of vapour phase decomposition Extracts from glass containers obtained during autoclave treatment were examined by ETAAS; the inner surfaces of the glass were examined post-extraction by SIMS and XPS Sample was digested in hydrofluoric and sulfuric acids and As was separated by solvent extraction with PhMe and back-extracted into water; the detection limit for As as oxide was 0.05 pg g-l the detection of B using multilayer crystal Application of wavelength dispersive instrument to Reference 931569 921446 1 9214522 931C342 931472 931568 931579 9 3 x 9 1 5 931C 15 19 9311981 9312046 9312041 9312520 93/26 12 9 312 7 4 5 9312893 9313 107 9214353 931768 9311989364R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix Fe Aluminium fluoride 0 Hafnium and zirconium fluorides P Borophosphosilicate glass films Si Silicate glasses Various (7) Fluorophosphate glasses Various ( 12) Glasses and ceramics Various (4) Glasses Various (4) Aluminium fluoride Various (9) Quartz Various Glass Various (1 6) Alkali silicates Various Optical glasses Technique; atomization; analyte form* MS;laser-ETV;S XRF:-:S XRF;-;S SIMS AE or MS;ICP and 1aser;L or S AA*-*- 3 MS;ICP and laser$ AA;ETA;S MS;ICP;L MS;ICP and laser$ AAS ICP-AES and XRF AA;ETA;L CERAMICS AND REFRACTORIES- A1 Lithium aluminate ceramics AE;ICP;S B Boron carbide MS;-;S B Boron carbide MS;-;S Ca Cement XRF;-;S Cr Aluminium nitride AA;ETA;L Fe Silicon nitride AE;ICP;S Fe Aluminium nitride AA;ETA;L Sample treatmentlcomments High-purity sample was atomized in a graphite cell under vacuum and the concentration of Fe determnied by three-step resonance photoionization using dye laser irradiation; detection limit reported as 4 x Use of a rhodium or chromium X-ray excitation source; a standard additions method was employed Method simultaneously measured both P and Si spectral intensities and corected for peak shift peak height changes due to chemical bonding effects g and Determination of surface silanol groups by detection Comparison of LA sampling and wet chemical of SOH+ cluster ion analysis procedures used in combination with ICP-AES and ICP-MS ]Review of AAS methods for the determniation of Al Ba Ca Cd Fe K Li Mg Na Pb Sr and Zn Laser ablation for semiquantitative determination of varous elements including Ca Mn Sr and Y in NBT SRM 6 12 glass !slurry of 50% suspended solids introduced directly into the atomizer for detection of Co Cu Fe and Ni; detection limits < 10 ng g-l suppression of boron volatilization from hydrofluoric acid solution; the method was applied to the detection of Li B Mg,Cr Mn Ni Co Cu and Zr Laser ablation of NIST SRM 6 I2 glass; detection of elements in the range 10-80 pg g-' Matrix was evaporated as SiF and trace metals were preconcentrated from water glasses by collector precipitation with hexamethyleneammonium hexamethylenedithiocarbamate and indium as the collector element Samples were fused and powdered and evaporated in a platinum crucible with hydrofluoric acid to remove silica and precipitated with sulfuric acid to remove lead; trace metals were preconcentrated as carbamates or dithiozonates and extracted with IBMK Study of the effect of mannitol dulcitol or sorbitol on Reference 9312601 931 199 1 931843 9312650 9214628 931630 931Cl 324 93/C1368 9312403 9312097 9312787 93f3108 Direct analysis of powder by introduction of ceramic ground to < 10 pm suspended in an aqueous slurry; recoveries > 95% Thermal ionization of the dicaesium metaborate cation for rapid and high precision measurement of isotope ratio for B Eloron was converted into sodium borate by fusion with sodium hydroxide or sodium carbonate directly on a rhenium filamen; B isotope ratios were measured directly on a rhenium filament Determination of calcium oxide in cement mix based on coal waste; samples were fused 1:5 with flux prior to analysis Sample (0.5 g) was decomposed with 6 ml sulfuric acid and 2 ml of nitric acid in a PTFE pressure veesl heated at 160 "C for 5 h Sample (0.05-0.5 g) was put into a 100 ml flask and diluted to volume with 0.5% (NaPO,) solution; the slurry was introduced into the ICP via a concentric nebulizer 93lC300 1 92143 15 9312994 9312 8 52 9311255 931 565 As for Cr 9311 255JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 365R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATER1ALS-continu~d Technique; atomization; analyte form* AE;FL Element Matrix La Rare earth concentrates Sample treatmentlcomments Selection of flame type and spectral conditions for As for Al Electrothermal vaporization of single spherical Samples were heated with a hydrofluoric determination; La measured as oxide at 441.8 nm particle (< I mg) into the ICP acid-hydrochloric acid mixture; subsequent addition of sulfuric acid and volatilization of fluorides allowed total dissolution hydrofluoric acid selection spectral interferences pressure vessels; different kinds of zirconia could be distinguished by REE composition Optimization of instrument parameters to minimize matrix effects and sectral interferences Sample (50 mg) was ignited at 850 "C dissolved in 50% hydrochloric acid and evaporated to dryness; the residue was mixed with 5 ml ethanol and diluted to 10 ml with 5% aqueous hydrochloric acid Comparison of three sample preparation methods dissolution with hydrofluoric-sulfuric acid under pressure; decomposition with ammonium sulfate and sulfuric acid in an open vessel; and fusion with lithium borate in a graphite crucible Sample was dissolved in nitric acid and the liquid was evaporated in the presence of graphite powder Description of a method for preparing standards for the determination of Co Cr Fe Mn and Ni impurities in tantalum niobium and vanadium carbides borides and nitrides Samples were introduced into the atomizer directly in the form of a 2.5% mlv slurry; detection limits were reported at the sub-pg g-' level for Cd Cr Cu Fe Mn Ni and Zn Examination of Al C N 0 Si and Zr in ICP exhaust gases generated by atomization of slurries Use of special graphite electodes and sodium chloride as a thermochemical reagent to improve evaporation Use of r.f.sputtering of alumina zirconia and lead lanthanum zirconate titanate as thin films prior to acid dissolution and determination of major components Appllication of derivative spectroscopy to minimize spectral interferences in the determination of Al Ce Cu La Pb and Sm atmosphere; recoveries for REEs were in the range 94- 1 12% Optimization of electrode shape and evaporation aid; sodium chloride was found to be most sutaible for determination of transition metals Comparision of slurry and wet chemical preparation methods for detection of impurity elements Comparison of techniques; sample was decomposed in hydrochloric-nitric-sulfuric acid mixture in an autoclave with a PTFE liner for ICP-AES analysis Y-Ba-Cu-0 type superconductors as a method of phase analysis Sample was digested without loss of Zr using Investigation of matrix effects and wavelength Application of high-resolution ICP-MS to removal of Samples were decomposed with sulfuric acid in PTFE Sample excitation using oxygen-argon controlled Apparatus described for the selective dissolution of Reference 93/27 28 93lC3001 93lC3003 931830 931566 931 128 1 93/C 1305 9312408 9 3lC3072 9313 175 Li Lithium aluminate ceramics Li Lithium aluminate ceramics AE;ICP;S AE;ICP and ETV;S Y Silicon nitride AA or AE;F or 1CP;L Zr Zirconium nitride film REEs Gadolinium oxide REEs Gadolinium oxide REEs Zirconium dioxide AE;ICP;L AE;ICP;L MS;ICP;L MS;ICP;L REEs Europium oxide REEs Erbium oxide AE;ICP;L AE;ICP;L Various (6) Lead zirconate-titanate AE;ICP;L 92/44 16 Various Superconductors Various (5) Non-oxide ceramics AE;a.c.arc$ XRF;-;S 92/45 19 9214540 Various ( I I ) Silicon carbide AA;ETA;S 9214 568 Various (6) Ceramic powders Various (5) Alumina EPMA AE;d.c.arc;S 931529 931532 Various (5) Oxide ceramics 931564 AE;ICP;L Various (6) Yttrium oxide Ae;ICP;L 931589 9316 16 Various (14) Holmium oxide AE;d.c.arc;S Various ( 13) Holmium oxide AE;d.c.arc;S 931659 Various ( 1 3) Silicon carbide Various (66) Silicon carbide AA or AE; ETA or AE;ICP;L 1CP;L and S and NAA 931758 931759 931766 Various (5) Superconductors AE;ICP;L366R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix Various (8) Superconductors Various ( 10) Zirconia powder Various (9) Superconductor Various (4) Superconductor Various (5) Superconductor Various (4) Superconductors Various (9) Silicon nitride Various (1 5 ) Titanium dioxide Various Zeolite process soluitons Various Titanate ceramics Various ( 17) Lead zirconate-titanate Various ( 12) Portland cement Various ( 14) Titanium dioxide Technique; atomization; analyte form* AE;ICP;L AE;ICP;L and S AE;arc;S AA;F;L AE;ICP;L AF;ICP;- A E; I CP; L XRF or AE;ICP;L XRF;-;L AE;ICP;L AE;ICP;L AES;ICP;L AE;ICP;L Various ( 10) Sintered alumina and zirconia AE;ICP;L Various (4) Yttrium oxide Various Perovskite ceramics Various Enamel frits Various (1 2) Silicon carbide MS;spark;S AE;ICP;L XRF;-;S AE;ICP and ETV;S Sample treatmentlcomments Dissolution method for determination of Fe Gd K La Mg Na Sn and Tm and major components with precision of <2% Four independent sample preparation procedures (fusion with ammonium hydrogen sulfate extraction separation by precipitation and slurry sampling) for the determination of Al Ca Cu Fe Mg Mn Na Ti V and Y IJse of double jet plasmatron for detection of Cr Co Mn Ni Al Si Fe V and Ti in Y-Ba-Cu-0 type material superconductor material using Y as an internal standard; minimum sample size 10 mg Detection of Bi Ca Cu and Si in bismuth-containing superconductor thin films !Sample was fused with sodium carbonate flux or other alkali fusion for determination of Al Ca Cr Cu Mg Fe Mn Ni and Zn trace elements including Cr Fe Hg Mg Mn Nb Ni P Pb Si Sn V Zn and Zr Detection of A1 and Na in aluminate solutions and Si and Na in silicate solutions used in zeolite preparation decomposition with ammonium sulfate and sulfuric acid and fusion with either lithium borate or sodium carbonate and sodium borate as sample preparation procedures for determination of macro-constituents hdethods for the determination of seven metal impurities and six dopants involving acid decomposition and fusion procedures Sample was fused with lithium borate in a graphite crucible for determination of Al Ca Cr Fe K Mg Mn Na Si Sr Ti and Zn; S was determined after fusion wuth sodium carbonate and potassium nitrate and extraction with water Sample (0.5 g) was heated with 10 g ammonium sulfate and 20 ml of concentrated sulfuric acid to dissolution; interferences were eliminated by matrix matching; detection limits were in the range 0.76-20 ng for Mg and Cu respectively sulfuric acid or 10 ml of a hydrofluoric-sulfuric (1 19) acid mixture in a PTFE vessel at 230 "C; alumina was decomposed in sulfuric acid alone; applied to detection of Al B Ca Cr Cu Fe Hf Mg Mn and Na Determination of Ce Cu Dy and Pb as oxides using isotope dilution approach Comparison of five sample preparation procedures including acid dissolution and fusion for determination of major and minor constituents Inter-element effects were compensated for using calibrations appropriate to Ca-rich and Ti-rich frits; results compare with those from wet chemical analysis Electrothermal vaporization of a slurried sample at 2 100 "C into the ICP in the presence of carbon tetrachloride as an evaporation aid Determination of Ag Al Pb and V in bismuth type Detection of major components (Ca Cu Pb Sr TI) Comparison of techniques for the determination of Comparison of acid pressure digestion Zirconia (0.3 g) was decomposed with 10 ml of Reference 931767 931774 931800 9311 243 9311 245 9311251 9311270 93lC1631 9311881 9312052 9312053 9312 142 9312 166 9312 192 9312626 9312668 931285 1 93/3 124JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 367R Table 3 SUMMARY OF ANALYSES OF ADVANCED MATERIALS-continued Element Matrix Various (4) Lanthanum oxide Technique; atomization; analyte form* Sample treatmentlcomments Sample (0.lg) was dissolved in 5 ml of 50% hydrochloric acid evaporated almost to dryness and the residue dissolved in I mol I-' hydrochloric acid and diluted to 10 ml with water; recoveries of Ce Nd Pr and Sm were in the range 93- 109Oh Various (28) Silicon nitride AE or MS;ICP;L Comparison of techniques; samples were passed and NAA through anion- and cation-exchange columns and W u was extracted by dithizone-chloroform prior to detection by gamma spectrometry were introduced into the ICP as aqueous slurries Various Silicon carbide AE;ICP;S Samples (4 g fine podwer with 3 pm particle size) Reference 931 3 1 30 9313 144 931335 I used in conjunction with the laser microprobe for the examination of polystyrene films (93/2372).Graphite furnace AAS rivals ICP-MS in its ability to provide a means of detecting ultra-trace levels of metals in polymer matrices. Polycarbonate is used as an optical material and it is important to determine the level of transition metals at ppb levels (931574). A graphite furnace AAS method was developed for the determination of Co Cr Cu Fe Mn Na and Ni using a solid sampling approach.The accuracy of the method was confirmed by comparative analysis. Applications to the analysis of optical fibres and polycarbonate disks were reported. Solid sampling has also been applied to the determination of Pb which is incorpor- ated as a stabilizer in poly(viny1 chloride) formulations (93/C138 93/2080). Approximately 3 mg of the solid plastic were introduced directly into the pyrolytic graphite coated ETAAS tube and atomized directly. No background correction was required and calibration was achieved using aqueous Pb calibration standards. A less sensitive analytical line was used for the determination of Pb in the range 0.1- 1 O/o m/m.Relative standard deviations in the range 5- 1 0% were reported for this met hod. Sample preparation methods for the determination of Sn in poly(viny1 chloride) by ETAAS have been described and compared (93/842). Procedures based on the decomposi- tion of the plasticized polymer in sulfuric acid and hydrogen peroxide or by dissolution in THF yielded detection limits for Sn of 0.4 and 2.7 pg g-l respectively. The THF method was reported to be simpler and less time consuming. Extraction procedures using nitric acid and diethyl ether were not found to be suitable for quantitative work. The application of glow discharge AAS to the examination of solid plastics including poly(viny1 chloride) by compaction with copper powder may also be of some interest (93/C1626).In a more extensive investigation GD- AES has been applied to the study of acrylic and polyester coatings and paint and lacquer layers on steel sheets used in the automotive industry (93K1497). It was claimed that the technique was applicable to both conductors and non- conductors alike although no details were given in the abstract concerning the construction of the atom cell. Continuous depth projiling of these materials was achieved for a number of elements simultaneously from surface dimensions (a few nanometre) up to a range of several hundred micrometres. Polymeric materials continue to be employed indirectly in the development of methodologies for the determination of trace elements.The use of polymeric substrates for the preconcentration of trace metals has continued with poly- urethane foam being the most popular choice (92/4418 92/4672 93/797 93/ 1 160). Macroporous poly(viny1thio- propionamide) chelating resin was reported to provide enrichment of trace noble metals with recoveries greater than 92% even after multiple re-usage (93/3252). In a related study a microporous poly(viny1phosphoramidic acid) resin was found to selectively adsorb Dy Er Ho and Yb ions from solution at pH 4-5. Poly(tetrafluoroethy1ene) has been used in slurry form as a volatilization agent for the determination of refractory elements by ETV-ICP-AES. Analytes such as B Cr Mo Ti and V (93/C3068) and Nb Ta U and Zr (93/C3073) were converted into volatile fluorides in the presence of the polymer and were easily vaporized into the plasma thus circumventing the prob- lems of carbide formation.The analysis of paints and coatings continues to be a subject of interest and a review of the application of ICP- AES in this area has been published (93/1250). The determination of Pb in paints in the field is becoming increasingly important for reasons associated with safety health and the environment. Portable XRF analysers are particularly suitable in this type of application (93/ 1842). An XRF detector was evaluated for the measurement of Pb in paint on military structures in West Germany (93/1772). It was found that a standardization approach could be used to compensate for the effect of the substrate on intensities. The unit was able to detect Pb base paint hidden by layers of Pb free paint.In an alternative approach to the problem laser induced breakdown spectroscopy (LIBS) was used for in situ detection of Pb in paint layers (93X1558). Laser pulses were focused on the painted surface to produce a micro- plasma which vaporized material and stimulated Pb atomic emission at 220.35 nm. It was observed that it was possible to generate depth profiles for paint layers by repetitive sampling at a fixed location. The components of the LIBS instrument were miniaturized in order to fit into a suitcase for portability. An LOD of 1% m/m was reported for Pb in paint using this instrument with a calibration range of up to 11% m/m. The direct analysis of paint chips for Pb using slurry sample introduction for ETAAS has also been reported (93/C1589).Several abstracts were received in the year under review concerning applications of atomic spectrometry in the paper industry. Wavelength dispersive XRF has been used in the detection of ring formation and failure of lime kilns and in the determination of pigment distribution in alkaline papers (93/1820). The chemistry of paper surfaces has been studied by SIMS imaging (93/1207). The sensitivity of the technique for elements such as Al Ca and Na allowed mapping at concentrations below those detectable by SEM-energy dispersive X-ray methods. It was reported that A1 was distributed less evenly over the fibre surface than the other elements. Laser ablation ICP-MS has been applied to368R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 the direct analysis of wood andcellulose materials (931C349).It was noted that the method could be used to rapidly analyse wood core samples according to date of growth. Solution nebulization of digested samples into the ICP-MS was reported to provide a satisfactory alternative approach. Sample preparation methods for the determination of Ca Cu Fe K Mn and Na (9311282) and Cd (9214452) by FAAS in pulp and paper have also been reported. 3.2. Semiconductor Materials 3.2.1. Silicon-based materials Non-destructive techniques play an important role in the characterization of silicon wafers. Perhaps the most signifi- cant advance in this field in recent years has been the advent of total reflection X-ray fluorescence spectrometry.Several reviews of the principles and applications of the technique concerning the surface analysis of semiconduc- tors have been published indicating the increasing popular- ity of the approach (9214632 9311892 9311990). A patent describing an instrument to be used for the detection of metal impurity on the surface of a single-crystal semicon- ductor may be of interest (9311910). The technique can be applied to the quantitative determination of surface con- taminants on silicon wafers (9311931). Calibration of response for Cu Fe Ni and Zn was achieved by use of a microdrop contamination of the wafer. Metal impurities in the wafers were shown to be condensed in a very small region near the centre of the dropped area. A relationship was derived between the intensity of the X-rays from the impurities in the condensed area and that from impurities distributed uniformly over the wafer surface in order to estimate analyte concentrations.Monochromatic excitation was used for grazing incidence XRF in order to improve penetration depth definition in depth profiling in modified silicon wafers (93/1983). A study was made of thin Cu and Ti metallization layers on silicon and of As dopant concentration profiles in wafers. It was reported that this technique could be used to investigate the effect of annealing non-destructively. Other applications of TXRF described include the detection of heavy metals in im- planted silicon (9311733) and the detection of the most important impurity elements (Cu Fe and Ni) in silicon ultra-large scale integration devices (931201 7).A study has been made of the removal of metal contamination on silicon wafers using dilute acidic solutions (93/1752). Wafers were cleaned using hydrochloric hydrofluoric nitric and acetic acids and residual Fe contamination was monitored by TXRF. It was found that hydrofluoric acid cleaning left a higher concentration of Fe on the wafers compared with the other acids. The study of the sources of contamination in semiconduc- tor materials and point-of-use high-purity chemicals re- quires the application of a variety of techniques. A recent paper cited the use of ICP-MS AAS TXRF and vapour phase decomposition in the investigation of cleaning and etching processes (93K1308). Both TXRF and ETAAS have been used in combination with the vapour-phase decomposition (VPD) preparation procedure as laboratory methods and for in-line monitoring (931C1306).The VPD procedure was also combined with ICP-MS to allow the measurement of more than 30 elements on wafer surfaces with LODs of the order of 1 x lo7 atoms cm-2. Metal impurities in silicon-on-insulator material were character- ized by TXRF (9311 192). The results obtained were compared with data obtained by AAS and SIMS. A comparison of the performance of TXRF and VPD-AAS for the detection of metallic impurities in silicon has also been reported (9312745). In the latter case TXRF was also used for VPD detection. There have been relatively few reports of the application of plasma emission spectrometry to the analysis ofsemicon- ductors in the period under review.Relevant methods are summarized in Table 3. The use of ICP-MS is beginning to predominate in such applications owing to the inherent sensitivity advantage over the emission technique and as a result of its speed in performing multi-element determina- tions (93x1 306). Extremely high sensitivity can be ob- tained by ICP-MS if electrothermal atomization is used instead of the more conventional nebulization approach for sample introduction (9312989). Both modes were employed for monitoring impurity levels in silicon and chemical cleaning baths used in large scale integration manufacturing processes. Another application of ETV-ICP-MS reported involved the analysis of photoresist used for very large scale integrated circuits (931568). Samples were diluted 10-fold with ethoxy ethyl acetate and a standard additions ap- proach was employed for the detection of Cu Fe Mn Na and Ni in photoresist.Detection limits for Fe and Na were reported as 0.06 ppb and 0.2 ppb respectively. Flow injection ICP-MS has also been applied to the determina- tion of trace metals on the surface of silicon wafers (931C371). The sample was prepared by treatment with hydrofluoric acid solution and vapour in order to etch the silicon oxide layer and collect the sample in a small volume. The FI system was used to inject samples of 20-500 pl into a carrier stream introduced into the ICP-MS instrument which then performed multi-element analysis. However for some elements unspecified in the abstract the FI-ICP-MS sensitivity was insufficient and measurement was achieved using ETAAS.A method involving cool plasma ashing for the determination of Th and U in electronic-grade chemi- cals by ICP-MS has also been described (93/C1307). An LOD of 25 ng kg-' was guaranteed for these elements using this approach which was also found to be suitable for 16 other elements of major interest. The results were verified by NAA analysis and Zeeman-effect ETAAS. Glow discharge mass spectrometry continues to be used for the analysis of semiconductors. Descriptions of a new discharge cell that can accommodate flat samples such as silicon wafers have now been published (93/C342,93/2 101 93/2226). It was claimed that this new design improved sensitivity as a result of increased silicon ion yield and detection limits as low as a few parts per trillion have been reported.The application of surface analysis techniques to the characterization of materials for the electronics industry has been the subject of various reviews. These include SIMS (92/4382 9214453 921446 1 92/4550) ion beam spectros- copies (921447 1) and electron and atomic force microscopy (93/2306). Several articles were published which summar- ize the development of sputtered neutral mass spectrometry and allied techniques (93/92/4478 9214522 9312464 93/229 1). However the majority of papers published on the analysis of silicon-based materials involve the use of secondary ion mass spectrometry. The accuracy of SIMS remains a subject of concern owing to the reliance on relative sensitivity factors. The basic requirements for quantitative SIMS analysis using caesium ion bombard- ment have been proposed (9312521). It was suggested that matrix effects observed arose from material dependent differences in sputtering yield and the diffusional transport of caesium to the bombardment surface.Close agreement was achieved in the Sics+ ion yields observed for silicon and silicon dioxide under conditions which minimized the build-up of caesium concentration at the sample surface. At an impact angle of greater than 60 degrees matrix depen- dent caesium coverage and the associated SIMS matrix effect were found to be small. Elemental sensitivities for 16 elements were obtained and in a comparison of the extreme case (in terms of high and low yield MCs+ ions) of A1 or ZnJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL.8 369R and As the difference in MCs+ yield ratio was about 30- fold. Factors affecting the quantification of C and 0 in silicon by SIMS have been studied (93/2972). The influence of primary ion beam current and primary ion beam sweep area on the determination of these analytes in silicon single crystals were investigated. It was found that a high primary ion beam current density was suitable for detection of 0 but medium density was recommended for the quantitative measurement of C in order to avoid high background intensities. The quantification of impurities or dopant species in the near surface region of semiconductor material by SIMS can be complicated by surface yield transients (93/2461). Such ion yield transients arise mainly from the implantation of the ion yield enhancing primary ion beam and can influence not only accuracy but also distort the shape of dopant profiles.The use of polyencapsulation oxygen flooding and low energy ion bombardment were evaluated as methods for the reduction of surface ion yield transients. It was reported that the use of low primary ion beam energies offered the additional benefit of reduced profile broadening as a result of cascade mixing. The internal indicator method was used to overcome matrix effects in the determination of As in silicon and silicon oxide interfaces (93/2577). Whilst such effects were further complicated by ion- and electron-enhanced segregation the proposed method was demonstrated to be a feasible if not comprehensive solution to the problem.Arsenic was found to be enhanced in the silicon phase by a factor of 4000. The determination of H in amorphous thin film silicon speci- mens using SIMS has been described (9312525). It was found that intensities from HCs+ ions produced under caesium primary ion bombardment correlated with H content in the hydrogenated thin films allowing the development of a quantitative method. A depth resolution of about 10 nm was obtained and using a focused beam lateral resolution of about 5 pm was achievable. A detection limit of 1019 H atoms cm-* was reported for a sputter erosion rate of about 1 nm s-l. The shape of secondary ion mass spectrometry depth profiles of B Ge and Sb in silicon have been studied (93/2460). These impurities were present in epitaxial layers grown by molecular beam epitaxy.The use of the data for the assessment of depth resolution and the implications for profile deconvolution were discussed. The depth distribu- tion of ion beam implanted gallium in crystalline silicon has been measured using SIMS (93/2459). The fabricated materials were examined using a 2 keV caesium ion bombardment at 60 degrees to normal with positive ion monitoring. It was established that implant ranges mea- sured correlated well with data derived from calculations but were shallower by 20-25 A. The segregation of Cu in silicon under oxygen ion beam bombardment has been studied by SIMS (93/2523). Changes in the decay length of the Cu signal were measured as a function of primary beam energy and angle of incidence.A strong dependence on incident angle was found and this was interpreted in terms of the nature of the altered layer formed under bombard- ment. Oxygen defects in Czochralski silicon have been examined by 3-dimensional SIMS using a camera-based imaging system (93/2382). Different manufacturing pro- cesses which gave rise to variations in the size and distribution of oxygen precipitates were monitored by the imaging procedure as well as by conventional depth profiling. Emphasis was laid on the characterization of the behaviour of the precipitate in the context of different annealing processes. Other applications of SIMS to the study of implantation processes and depth projling which may be of specific interest are the investigation of axial channelling of B in silicon (93/2383) diffusion of F in silicon and polysilicon (93/854) and concentration profiles of N in silicon implanted during thermocycling (92/4460).Silicon-germanium structures are of interest to the electronics industry because of potential for increased speed bandgap engineering rapid oxide growth and low processing temperatures for device applications (9312573). Epitaxial silicon-germanium thin films have been devel- oped using molecular beam epitaxy and chemical vapour deposition reactor systems (93/2363 93/25 13 93/2573). Rutherford backscattering spectrometry Auger electron spectrometry SIMS and transmission electron microscopy were used to study the As-deposited and oxidized films. The measurements detailed in the abstract included the deter- mination of Ge content and distribution and dopant concentrations within the film; the build-up of Ge at oxide interfaces and of oxygen at interlayer interfaces; and film thickness.It was noted that excellent agreement could be obtained using the various analytical techniques when appropriate calibration standards were used to determine Auger and SIMS sensitivity factors and sputter rates (93/2363). A silicon-germanium multilayer structure has been studied using a high-resolution depth profiling tech- nique (93/2456). Molecular oxygen ion beam etching was used in combination with imaging X-ray photo-electron spectrometry in order to examine the surface chemistry of the material under the conditions obtaining in SIMS characterization. The advantages and disadvantages of this approach were explored in the study of Si/Si(0.75)Ge(0.25) structures.The process of depositing a metal as a sputtered film on a semiconductor material is often referred to as metalization. Depth profiling of aluminium metalization of silicon by Auger or SIMS is impeded by severe sputter-induced roughening which causes a serious loss in depth resolution (9312570). A study was made of the effect of optimization of bombardment angle sample rotation during sputtering and the use of heavy or reactive ions. It was found that by using molecular oxygen ions instead of argon and employ- ing sample rotation sample depth resolution was improved by a factor of 10 compared with that obtained using routine operational parameters. In a separate SIMS investigation it was found that in addition to improving depth resolution sample rotation prevented bombardment-induced topogra- phical formation (93/2574).Rotation of the sample did not significantly affect the implant shape but did result in better characterization of the interface layer. Using molecu- lar oxygen ion bombardment silicon sputtered at twice the rate of aluminium under the conditions used. The use of sample rotation allowed the correct sputtering rate to be applied to the layer and substrate and thereby provide a much more accurate depth scale than could be established without rotation. Thus B was detected below 1 ppm using sample rotation and B at the aluminium/silicon interface was clearly defined. Depth projling of A1 thin j l m s on silicon substrates was also carried out using SIMS (93/2499).In the latter case profiling was performed using oxygen in the ion beam source or in the analytical chamber. The experimental results were compared with data ob- tained by dynamic Monte Carlo simulation. 3.2.2. Gallium arsenide-based materials As in the case of silicon-base semiconductor materials the application of SIMS continues to dominate the characteri- zation of gallium arsenide and related materials. A detailed compilation of SIMS ion yields of electronically important impurities in gallium arsenide and associated materials has been published (92/4439). The ionization efficiencies for 16 elements in gallium arsenide were measured. Highly doped crystals analysed by wet chemical methods and ion im- planted samples were examined as reference materials.The ion yields were used to study matrix effects in order to provide corrections to allow quantiJication by SIMS. The370R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 problem of achieving accurate quantification of impurities in the SIMS analysis of gallium arsenide has been examined at a fundamental level (93/1279). The influence of the operating parameters of a quadrupole SIMS instrument including secondary ion optics electron multiplier and target potential on performance were studied. The effect of oxygen flooding on secondary ion yield and SIN were also investigated. A fast xenon atom bombardment source and a photographic detection MS (resolution 5000) were em- ployed to obtain secondary ion mass spectra of a range of materials including gallium arsenide (93/26 12).Detection limits for the technique which was applied quantitatively for 27 elements ranged between 1010-1013 atoms cm-2. Surface contaminations on gallium arsenide wafers were analysed by time-of-flight SIMS and temperature depen- dent and angle resolved X-ray photoelectron spectrometry (93/2962). The dependence of the composition chemical state and diffusion behaviour of the passivating thermal oxide on different annealing temperatures was studied. No metal impurities were found within the sensitivity of the time-of-flight SIMS method at ambient or elevated temper- atures. A quantitative SIMS method for the determination of the composition of aluminium gallium arsenide and dopant Mg concentration has been published (93/22 16).Caesium cluster ions formed by collision with the matrix atoms were measured in positive ion mode. The ratio of AlCs+ ion intensity to that of an AsCs+ ion increased linearly and the relative sensitivity factor of a MgCs+ ion to an AsCs+ ion showed a constant value in relation to a reciprocal change in A1 and Ga content in the structure. The method was proven to be accurate for Al As Ga and dopant Mg in an unknown sample. The incorporation of Be in gallium arsenide-aluminium gallium arsenide heterostructures has been examined by SIMS (93/2961). Depth profiling of layers grown by molecular beam epitaxy indicated that the gallium arsenide material was doped with Be at a level of 2 x 1019 atoms cm-2 and that negligible Be diffusion occurred under the growth conditions used.Resonance ionization mass spectrometry has also been used for quantitative depth profiling of Be-doped gallium arsenide- aluminium gallium arsenide heterojunction bipolar transis- tors (93/2465). It was claimed that the technique allowed the elucidation of dopant migration as a result of freedom from matrix effects commonly found in SIMS. The magni- tude of dopant (Be) and matrix (Al) signals were related in proportion to concentration and quantification was pos- sible without extensive use of standards. Only a few abstracts were received concerning the use of AAS or AES for the analysis of gallium arsenide and related materials. An atomic absorption method was developed for layer by layer detection of impurities such as In and Sb in films of cadmium telluride on a gallium arsenide substrate (9214507).Layers were removed by etching with 2.5% bromine in hydrobromic acid. Impurities were detected by ETAAS with Zeeman-effect background correction. Detec- tion limits for In and Sb were reported to be 1.3 x 1 01* and 1.2 x lo1’ atoms ~ m - ~ respectively when the thickness of the layer removed was 0.3 pm. The electrical properties of gallium arsenide are to some extent dependent on the quality of the arsine used in the chemical vapour deposition process. The direct analysis of arsine requires specialized handling techniques for reasons of toxicity and safety and is hindered by a lack of suitable gaseous standards (93/2047). A static plasma was developed for handling toxic and reactive gases in which the plasma gas and sample were enclosed inside a quartz container.An additive gas was added to the argon discharge and after stabilization the sample was added. The container was then sealed to isolate the discharge. The selection of additive gas flow rate discharge container geometry and instrumental parameters were discussed. The qualitative determination of C Fe Ge Mg Mo Sn and V in arsine was reported. The analysis of high-purity gallium by high-resolution EDMS has been described (9312893). A special technique for the prepara- tion of gallium samples involved cryocooling of the liquid metal. The surface of the solid gallium sample prepared in this way was found to be essentially free of surface contamination. It was reported that the determination of over 70 impurity elements in gallium was possible in a single analytical measurement.Detection limits were nomi- nally better than a few ppb on a mass basis with accuracies within 40%. It was noted that detection limits for C Cl H 0 N and Ta were at the ppm level and were limited by contamination. 3.2.3. Cadmium mercury telluride and indium phosphide based materials A variety of techniques have been used to examine thin films and epitaxial layers of cadmium mercury telluride. A method was developed for the determination of the composition of cadmium mercury telluride epilayers using negative ion SIMS (93/2327 93/2467). A caesium primary ion beam was employed and it was reported that the Te secondary ion yield correlated linearly with the Cd mole fraction.Consequently it was possible to achieve quantifi- cation based on variations of the matrix-induced ion yield for Te. The method was applied to the characterization of chemical vapour deposition grown heterostructures. In another study of this type of process EDXRF was used to determine stoichiometry and thickness of epitaxial layers of cadmium mercury telluride being developed for infrared optoelectronic devices (9311 687). It was noted that whilst PIXE could be used to determine stoichiometry over a wafer the cost of accelerator time and beam damage made it unsuitable as a technique for production control. Conse- quently an EDXRF using americium as the excitation source was developed. It was reported that after correction for secondary fluorescence effects the EDXRF technique gave results indistinguishable from those obtained using PIXE.Electron microprobe microanalysis has been used to study the chemical states of atoms in cadmium mercury telluride via X-ray emission spectroscopy (92/4583). A chemometric approach was used to reveal the effects of weak chemical interactions. Depth profiling of In doping of epitaxial layers of cadmium mercury telluride was carried out in another study using SIMS and at higher concentra- tions photon induced X-ray emission spectrometry (93/3 107). The quantification of bulk impurity levels in the material was carried out by ETAAS. The sample (0.5 g) was dissolved in a hydrochloric-nitric acid mixture and diluted 25-fold. L‘vov platform atomization was used for the detection of Ag and Cu at 328.1 and 324.8 nm respectively.Indium was determined separately using tube wall atomiza- tion. Details of a new sampling technique for ETAAS based on sputtering have now been published (93/1640 see also J. Anal. At. Spectrom. 1992 7 381R). The technique was applied to the determination of In in cadmium telluride monocrystals. The material was sputtered onto a L’vov platform which was then introduced into the graphite furnace tube where the sample was atomized without further thermal pre-treatment. The content of In dopant was reported as 573 ppm for the sputter method compared with 400 ppm as determined by a dissolution pre-treatment followed by flame AAS. It was noted that whilst the method could be applied to other materials calibration of response remained the main problem.Finally laser enhanced ioniza- tion has been applied to the determination of In in cadmium mercury telluride and Cu in germanium (92/4623). A rod-in-flame atomizer was used to examine solid samples of the material directly. It was observedJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY. DECEMBER 1993 VOL. 8 371R that this approach resulted in a decrease in the matrix background signal of more than two orders of magnitude enabling detection limits in the sub-ppb range to be achieved. An XRF method has been proposed for the determination of indium in thermoelectronic material (93/2725). A small area on the natural cleavage face of a layered single crystal of bismuth indium selenide was examined non-destruc- tively using a wavelength dispersive instrument. A screen- ing mask of phosphor bronze was used to define a 2 x 12 mm region of the crystal which was fixed to the rear of the mask with adhesive tape.Net X-ray intensities were used for calibration and validated by extraction-photometric analysis of crystals after exposure. The concentration and distribution of impurity species in bismuth tellurium selenide thermoelectric semiconductors has been studied by SIMS (93/2367). Bromine-doped samples were made by hot pressing and it was found that alkali and oxide impurities were located preferentially in regions between grains or along grain boundaries. In a further related study SIMS was employed to examine Br and 0 ion intensities as a function of parameters used in the hot press preparation (93/2368).A strong correlation between hot press condi- tions and Br ion concentration was identified. The application of SIMS to the analysis of indium phosphide and related semiconductor materials was the subject of a recent review (9312500). An increase in the sensitivity of SIMS analysis of indium phosphide was reported for a method involving the detection of cluster molecular ions under caesium bombardment. It was found that with a low mass resolving power virtually all elements studied (Al Cu Ge Pb Sb Sn Ti and Zn) could be detected with detection limits of the order of atoms cm-* or better. The exceptions to this were Mg and S which were subject to interference by residual vacuum contaminants. Spatially resolved SIMS was used to study striations in doped indium phosphide wafers (93/2475).Line profiles of Fe Ga and Sb present in the material as dopants were found to be related to striation patterns. A paper concerning the surface concentrations of In 0 and P in indium phosphide single crystals after exposure to Gamble solution may also be of interest (93/2890). 3.3. Glasses Ceramics and Refractories 3.3.1. Glasses Relatively few novel methods were reported in the year under review concerning the analysis ofglasses. A review of AAS methodology by workers from Corning may be of interest (93/630). The main development in terms of technique was the use of direct laser sampling of solid glasses. Moenke-Blankenburg et al. (92/4628) published a paper on the quantitative analysis of glass using two laser sampling devices in conjunction with ICP-AES and ICP- MS.Analytical results for three fluorophosphate glasses obtained by five methods including conventional dissolu- tion procedures were compared. It was concluded that the laser based solid sampling offered the means of obtaining rapid quantitative multi-element analysis. The use of LA- ICP-MS for semiquantitative analysis of glasses has been described (931C1324). In this work NIST glass SRM 612 Glass Trace Elements was analysed quantitatively by dissolution followed by ICP-AES and by direct solid sampling using LA-ICP-MS. It was reported that the semiquantitative results obtained by LA-ICP-MS were found to be in good agreement with the certified data. The advantages of using a Q-switched Nd:YAG laserprobe for ICP-MS for the analysis of glasses has been discussed (93/C3014). It was observed that LODs of 30 ppb could be achieved using material from sample crater sites of the order of 30 pm in diameter.High magnification video viewing was claimed to allow the identification of samples as small as 1 pm for analysis. In a separate study LA-ICP-MS was applied to the semiquantitative bulk analysis of NIST SRM 612 Glass Trace Elements (93/2097). Analytes were detected in the sample in the range 10-80 ,ug g-l. The performance of LA-ICP-MS has been compared with GDMS for the analysis of glasses (93K1335). In order to sustain the d.c. GD during the sputtering of insulating material such as glass a conducting cathode made of tantalum was placed close to the sample. The metal from the cathode sputtered onto the glass causing re-sputtering of the sample into the argon discharge.It was observed that both the LA and GD techniques were able to determine elements at ppm levels with better than 5% relative precision. The surface chemistry of glasses is important in many industrial applications. A time-of-flight SIMS study of the incorporation of aluminium into the silane coating on E- glass fibres has been published (93/2271). It was confirmed that A1 from the glass surface was integrated with the silane coating of the coupling agent. The determination of surface silanol groups on silicate glasses has been carried out using static SIMS (9312650). This was achieved using detection of SOH+ cluster fragment ions. Absolute detection was achieved using calibration reference standards of quartz.The technique developed was applied to the analysis of soda-lime glass and silica films. A summary of other applications involving the analysis of glasses is provided in Table 3. 3.3.2. Ceramics and refractories Industrial interest in the properties and applications of advanced ceramic materials has led to a requirement for suitable analytical techniques for analysis and characteriza- tion. Specific reviews of the applications of LMMS (93/2290) and SIMS (92/4501) in this field have been published as has a more general overview of a range of analytical techniques (93/ 1670). The development of methods for the analysis of non- oxide ceramics such as refractory carbides and nitrides has continued in the past year. Non-oxide materials are difficult to dissolve and a number of wet chemical sample prepara- tion regimes for the analysis of silicon carbide (93/758 93/759) boron carbide (93/2994) silicon nitride (93/830 93/1280) aluminium nitride (93/1255) and zirconium ni- tride (93/566) have been published (see also Table 3).Most dissolution procedures are time consuming and progress continues to be made in the application of more direct methods such as slurry sampling (see also J. Anal. At. Spectrom. 1992 7 384R). This approach remains most popular when used in combination with direct nebulization of the slurry into an ICP and seems to be successful in application to the analysis of silicon nitride (921C4225 93/565) and silicon carbide (93/C376 93/529 93/758 931335 1). However viable methods based on the introduc- tion of silicon carbide slurries into an electrothermal atomizer prior to direct analysis by AAS have also been published (92/4568 93/758). Difficulty in the atomization of refractory materials remains a problem for the determi- nation of some elements particularly if present at high concentration. In a number of instances NAA has been used as a comparative technique for validation purposes or to extend the range of elements analysed (9214568 93/759 931830 93/3 144).Slurry sample introduction was combined with ETV for the introduction of silicon carbide samples into an ICP for AE detection (93/3124). In order to avoid difficulties associated with incomplete atomization from the graphite furnace used vaporization was carried out at 2100 "C in a stream of argon containing carbon tetrachlo- ride.The ratios of peak intensities for 12 elements in the presence and absence of carbon tetrachloride were in the372R JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 range 1 - 1 500. Background equivalent concentrations were improved by a factor of 2-20 for these elements in comparison with a conventional dissolution approach. Complete vaporization of all components was achieved for a 1 mg sample but it was noted that minor components could be completely evaporated from samples up to 10 mg in mass. A similar approach was adopted for the determina- tion of trace elements in aluminium nitride by direct sample insertion (93/3 197). Solid samples were introduced into the ICP in a graphite cup and for refractory or carbide forming elements in-plasma halogenation was effected by passing carrier gas through freon 113.Detection limits at the ppm level were reported. The application of glow discharge techniques to the analysis of ceramics continues to be the subject of discus- sion. Analysis of ceramic materials has been achieved using microwave-boosted GD-AES (93/C 1480) and r.f. GDMS (93/1480). The use of auxiliary boosting of the discharge avoids the requirement for the sample to be conducting and opens up the possibility of achieving depth p r o j h g . Thus an r.f. GD source was utilized in the analysis of silicon nitride alumina and zirconia by AES and MS (93/59 1). X- ray fluorescence can be used to examine non-conducting samples directly and applications to the characterization of silicon nitride (93/ 1723) and refractory carbides borides and nitrides (92/4540) may also be of interest.Lead zirconate-titanate electroceramics are advanced materials with a perovskite-type structure. The stoichiome- try of these materials at the macroconstituent level affects a wide range of their functional properties. Transition metals are used as dopants in such materials to achieve suitable ferroelectric or piezoelectric properties. Several analytical methods have been developed and compared for the determination of dopant and impurity concentrations in lead zirconate-titanate by sample decomposition and ICP- AES (92/4416 9312053 93/2668). These involved acid decompositions under pressure; decomposition with am- monium sulfate and sulfuric acid; fusion with lithium borate; and fusion with sodium borate and sodium carbo- nate. It was noted that the presence of decomposition reagents in the sample presented to the ICP resulted in a significant decrease in analyte intensity.Matrix-matched standard solutions were used for calibration. Good agree- ment between dissolution and fusion methods was re- ported. These sample preparation methods were also found to be suitable for the determination of macroconstituents in lead zirconate-titanate including gadolinium- and lan- thanum-modified forms and other advanced ceramic ma- terials including barium titanate- and calcia-stablized zir- conia (931'2052). The determination of trace impurity elements in zircon- ium dioxide is problematic because of the resistance of the material to chemical attack.Four independent procedures for the determination of up to ten metals by ICP-AES have been described (93/744). These included fusion with am- monium hydrogensulfate; separation of zirconium by ex- traction from nitric acid with 2-thenoyltrifluoroacetone in xylene; matrix separation by precipitation as zirconium oxychloride from a hydrochloric acid-acetone medium; and slurry sample introduction utilizing ultrasonic disper- sion of the powder in hydrochloric acid. It was reported that matrix matching was not required in any case and calibra- tion was achieved by use of the standard additions procedure. The results obtained for all procedures were found to agree for Al Ca Fe Mg Na Ti and Y. Good agreement was also obtained for the separation methods for Cu Mn and V but the concentrations of these metals obtained by the method without matrix separation were considerably higher.The application of ICP-MS to the determination of REEs in zirconium oxide has been reported (93/2408). Samples were pressure digested in PTFE vessels with sulfuric acid. It was reported that three types of zirconium dioxide powder could be identified from the impurity contents of REEs at 200 ppm and those present at less than 10 ppm. An XRF method has been described for the determination of zirconium dioxide in mineral raw material and processing products (93/1765). Samples were fused in a mixture (1 :4 1) of lithium tetrabo- rate lithium metaborate and silica in a glassy carbon crucible. It was noted that the accuracy and productivity of the procedure could be improved if the fusion was per- formed at 850-880 "C with the application of ultrasound for 2-4 min.Methods for the analysis of mineral zircon by solution and LA-ICP-MS may also be of interest (93/1004 93/ 1054). A pressure acid decomposition procedure has been developed for the determination of trace impurities in sintered zirconia and alumina by ICP-AES (93/2 192). There were few abstracts of interest received pertaining to the analysis of alumina perhaps indicating that adequate methodology is now established in such applications. The analysis of lithium aluminate ceramics has received some attention. A slurry method has been developed for the determination of A1 and Li in such materials (93/C3001).The sample was ground to a particle size of less than 10 pm and introduced into the ICP in an aqueous suspension. Recoveries of the analytes were greater than 95% and the method could be carried out in less than 30 min. In a related study the direct analysis of discrete spherical particles of lithium aluminate weighing less than 1 mg each was achieved using ETV into the flame of an AAS instrument or into an ICP (93lC3003). The particles were analysed individually by sealing them in a small cavity between two porous graphite rods which were then heated rapidly to 3000 "C. The vaporized sample was swept in an argon carrier stream to the detector. Quantification was achieved for Li and trace elements using standard solutions or other reference materials. Abstracts continue to be received concerning the prob- lems of determining rare earth elements in their oxide matrices by ICP-AES.A summary of such methods is provided in Table 3 (see also J. Anal. At. Spectrorn. 1992,7 382R). Methods based on mass spectrometry offer a greater degree of spectral selectivity in addition to providing high sensitivity for REEs (93/2362). The capabilities of a range of techniques including ICP-MS SSMS SIMS laser de- sorption MS and TIMS for the study of REE compounds was reviewed. It was noted that several of the techniques were able to provide localized structural information in addition to surface and bulk quantification. This was illustrated in a publication concerning the application of laser ablation ICP-MS to the analysis of cerium oxide ceramics (93lC2225).The instrument was used to provide both bulk and feature analysis of the sample including discrete analysis of inclusions less than 50 pm in diameter. The performance of the system for the determination of oxygen was also discussed. The interference of rare earth oxides on the determination of trace impurities by ICP-MS can cause difficulties in quantification (93/C13 12). The use of electrothermal vaporization as a means of sample introduction for ICP-MS was shown to provide reductions in the level of spectral interferences observed in the determination of 14 REEs in a gadolinium oxide matrix. This was attributed to the prevention of oxide formation arising from solvent molecule interactions. Detection limits for 12 REEs using this procedure were one order of magnitude better than the equivalent data for conventional nebulization.The ETV-ICP-MS approach enabled the determination of Lu and Yb at the level of 100 ppb in solid samples although it was noted that a residual oxide interference remained. This problem was overcome by theJOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY DECEMBER 1993 VOL. 8 373R use of a high-resolution ICP-MS system (93lC1305). Trace element impurities in yttrium oxide and gadolinium oxide were determined using a mass resolution of 400. The specific spectral interferences caused by gadolinium oxide hydride and hydroxide ions on Lu Tb Tm and Yb were avoided by optimizing the instrument for the detection of doubly-charged ions. Detection limits obtained in this mode were in the range 0.05-3 ng 1-l.If singly-charged ions were used for measurement LODs in solution were reported to be in the range 5-30 pg 1-I. Finally the characterization of novel superconducting ceramics remains a subject of interest. Relatively routine methods for bulk analysis involving wet digestion and ICP- AES continue to be published and a summary of these is provided in Table 3. The determination of the component composition of Y-Ba-Cu-0 superconductors has been carried out by SIMS using an argon ion beam source (92/4683). The technique was also used for component profiling of single crystals and thin films. The morphology and lateral homogeneity of superconducting Y-Ba-Cu-0 films was the subject of another SIMS study (93/2516). High-resolution glow discharge mass spectrometry has been applied to the analysis of high-temperature superconductors (9312360).Pin samples of Y-Ba-Cu-0 material were examined while being maintained at temperatures near liquid nitrogen levels by cell cryocooling. It was claimed that the matrix independence of the technique obviated the need for reference standard materials. Applications of AES for the study by LA of superconducting materials may also be of interest (9311 948 9313285). LOCATION OF REFERENCES The full list of references cited in this Update have been published as follows 9214074-9214734 J. Anal. At. Spectrom. 1992 7(8) 389R-4 1 1 R. 93lCl-93lC997 J. Anal. At. Spectrom. 1993 8( I) 45R-78R. 931998-93lCl354 J. Anal. At. Spectrom. 1993 8(3) 137R-149R. 93lC1355-9312093 J. Anal. At. Spectrom.1993 8(4) 169R-194R. 9312094-92127 10 J. Anal. At. Spectrom. 1993 8(5) 239R-262R. 931271 1-93/3353 J. Anal. At. Spectrom. 1993 8(7) 313R-336R. Abbreviated forms of the literature references quoted (excluding those to Conference Proceedings) are given on the following pages for the convenience of the readers. The full references names and addresses of the authors and details of the Conference presentations can be found in the appropriate issues of JAAS cited above. Abbreviated List of References Cited in Update 9214293. Bull. Chem. SOC. Ethiop 1990 4 13. 9214313. Chin. Chem. Lett. 1990 1 235. 9214323. Dokl. Bolg. Akad. Nauk. 1990 43(10) 57. 9214341. Ganguang Kexue Yu Kuang Huaxue 1991 9 71. 9214382. Int. Wiss. Kolloq. Tech. Hochsch. Ilmenau 1990 35 144. 9214416.Mater. Sci. Monogr. 1991 66C 1919. 9214417. Mater. Trans. JIM 199 1 32 480. 9214418. Mendeleev Commun. 199 1 75. 9214439. NTT R&D 1991 40 373. 9214452. Papier (Darmstadt) 199 1 45 285. 9214453. Period. Polytech. Chem. Eng. 1990 34 81. 9214459. Polym. Test. 1991 10 3 1. 9214460. Poverkhnost 199 1 6 1 5 1. 9214461. Pover- khnost 1991 8 5. 9214464. Prepr.-Am. Chem. SOC. Div. Pet. Chem. 1991,36 31 1.9214465. Prepr. Pap. Am. Chem. SOC. Div. Fuel Chem. 1991 36 1180. 9214471. Proc. Electrochem. SOC. 1991 91 342. 9214478. Prog. Surf Sci. 1991 36 35. 9214501. Seramikkusu 1991 26 520. 9214507. Sib. Khim. Zh. 1991 2 51. 9214522. Thin Solid Films 199 1 200,293.9214527. Trends Anal. Chem. 199 1 10,23.9214538. Vopr. Khim. Khim. Tekhnol. 1989,90,34. 9214540. 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