摘要:

1144 SHORT PAPERS Analyst, Vol. 108 Spectrophotometric Determination of Some Pyrazolidinedione Derivatives in Pharmaceutical Preparations Michael E. El- Kommos Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Univevsity of Assiut, Assiut, Egypt Keywords : Pyrazolidinedione derivative determination ; spectrophotometry ; p-dime thy lavninocinnamaldelzyde ; p lt ar maceuticals Pyrazolidinedione derivatives constitute a very important class of medicinally active com- pounds. Phenylbutazone (4-butyl-l,2-diphenylpyazolidine-3,5-dio1~e) (PB j and oxyphenbut- azone [4-butyl-l - (4-hydroxyphenyl) -2-phenylpyrazolidine-3,5-dione monohydratej (OPB j possess analgesic, antipyretic and anti-inflammatory actions. They are effective in counter- acting rheumatoid arthritis and other rheumatic conditions.Sulfinpyrazone [l,2-diphenyl- 4-(2-phenylsulphinylethyl)pyrazolidine-3,5-dione~ (SPj is a potent uricosuric agent. The official alkalimetric BP 1980 method of determination1 for pyrazolidinedione deriva- tives and their dosage forms lacks selectivity and sensitivity. Moreover, non-cornpendial formulations of pyrazolidinedione derivatives that contain aluminium hydroxide, and other formulations that contain basic or acidic substances, cannot be assayed by the official method. In this work, a simple, accurate, sensitive and selective method is reported for the quantita- tive determination of PB, OPB and SP in bulk and in pharmaceutical preparations. Experimental Materials Pharmaceutically pure phenylbutazone, oxyphenbutazone and sulfinpyrazone (Ciba- Geigy Ltd., UK) were used.As pharmaceutical preparations, various commercially available tablets (phenylbutazone, Adco ; Curazolidine, Kahira ; Curapyrine, Kahira ; Oxyzone, Nile ; Tanderil, Ciba-Geigy ; and Rhumaxin, Alex. Co.) and ampoules (Curazolidine, Kahira) were used. In addition, synthetic mixtures of phenylbutazone with aluminium hydroxide, Novalgin, ascorbic acid, or aspirin were prepared by mixing in equal amounts.September, 1983 SHORT PAPERS 1145 Reagents A 0.5% m/V 9-dimethylaminocinnamaldeliyde (Sigma, USA) solution in methanol was freshly prepared. Apparatus A Zeiss PM2 DL spectrophotometer (West Germany) was used. Preparation of Samples Powder forms in glacial acetic acid and dilute to 100.0 nil with the same solvent. solution to 10.0 ml with glacial acetic acid.Weigh accurately about 25 mg of PB, OPB or SP working standard or sample, dissolve it Dilute 5.0 ml of this Tablets Dry by wrapping between two filter-papers, then in a hot-air oven at 105 "C for 10 min. Weigh and powder 20 tablets. Extract an amount of the powder equivalent to 25 mg of PB, OPB or SP with 20-, 10- and 10-ml aliquots of glacial acetic acid. Filter the combined extracts through a sintered-glass funnel and wash the residue thoroughly with glacial acetic acid. Adjust the volume of the combined filtrate and washings to 100.0ml with the same solvent. Dilute 5.0 ml of this solution to 10.0 ml with glacial acetic acid. First remove the tablet coating by rinsing carefully under tap water. Ampoules acetic acid. volume with glacial acetic acid.solvent. Mix the contents of five ampoules and dilute 0.5 ml of the mixture to 100.0 ml with glacial Pipette 25.0 ml of this solution into a 100-ml calibrated flask and make up to Dilute 5.01nl of this solution to 10.0 ml with the same Absorbance measurements To 1.0 ml of sample solution, add 2.0 ml of hydrochloric acid and heat on a boiling water- bath for 30min. Cool to room temperature under running water and add 10.0ml of methanol and 2.0 ml of 9-dimethylaminocinnamaldehyde (PDAC) solution. After 15 min, dilute to 25.0 ml with methanol and measure the absorbance of the solution at the specific wavelength of maximxm absorption, Amax. (526 nm for OPB and 540 nm for PB and SP), against a blank similarly treated using 1.0 ml of glacial acetic acid instead of the sample solution.1 400 440 480 500 560 600 640 Wavelengt h/n m Fig. 1. -4bsorption spectra of the chromogens obtained from 1, yhenylbutazone, 2, oxyphen- butazone ; and 3, sulfinpyrazone. Concentration for final solution, 5.0 pg ml-I.1146 SHORT PAPERS Analyst, Vol. 108 Stoicheiometric relationship Job’s method of continuous variation was employed for stoicheiometric analysis2 Standard solutions of PB, OPB and SP (4 x 1 0 - 3 ~ ) in glacial acetic acid and of PDAC (4 x 1 0 - 3 ~ ) in methanol were prepared. A series of standard solutions of the drugs (0.0, 0.1, 0.2, 0.3, 0.4, . . ., 1.0 ml) were made up to 1.0 ml with glacial acetic acid, and 2.0 ml of hydrochloric acid were added. The mixtures were heated on a boiling water-bath for 30 min, each mixture was diluted with 10.0 ml methanol and then complementary volumes of PDAC solution (1.0, 0.9, 0.8, 0.7, 0.6, .. ., 0.0 ml) were added. After 15 min, the absorbances of the solutions were measured at the specific Amax. against a reagent blank. Results and Discussion The investigated pyrazolidinedione derivatives, on heating with glacial acetic acid and hydrochloric acid, are hydrolysed into hydrazobenzenes, which undergo benzidine rearrange- ment3 to give benzidine or o-semidine. The reaction product forms a pink or orange - red protonated Schiff base with PDAC. Absorption spectra of the coloured products resulting from the three pyrazolidinedione derivatives are shown in Fig. 1. The chromogen obtained from PB has a Amax. of 540 nm and a molar absorptivity (Emax,) of 6.51 x lo4 1 mol-l cm-l, that obtained from OPB has a Amax.of 525 nm and an Emax. of 2.42 x lo4 1 mol-1 cm-1 and that obtained from SP has a Amax. of 540 nm and an Emax. of 6.11 x lo4 1 mol-1 cm-l. Monophenylbutazone did not produce any colour, because on hydrolysis it gives phenylhydrazine, which does not interact with PDAC. It must be noted that the chromogen obtained from OPB has a maximum absorption at a shorter wavelength and molar absorptivity of about half that obtained from PB or SP. This may be due to rearrangement of the hydrolytic product of OPB into an o-semidine and not into a substituted benzidine derivative. Moreover, the continuous molar variation of pyrazolidinedione derivatives and PDAC showed that the rearranged hydrolytic product of PB and SP interacts with PDAC in the ratio 1:2, while that of OPB interacts in the ratio 1 : 1 (Fig.2). 0.8 0.6 0 0 e 2 0.4 Q a 0.2 0 0 [Pyrazolidinedione]/[pyrazolidinedionel + IPDACI Fig. 2. Continuous variation graphs obtained from pyrazolidinedione derivatives and p-dimethylaminocinnamaldehyde solu- tions (4 x M ) : 1, phenylbutazone; and 2, oxyphenbutazone. The conditions for the production of the most intense and stable colour were studied. The presence of 2.0 ml of hydrochloric acid and heating for 30 min on a boiling water-bath were required for complete hydrolysis. Before addition of PDAC, it was found necessary to lower the acidity by dilution with methanol. The absorbances of the resulting solutions were found to increase with increasing PDAC concentration up to 0.6 mg ml-l in the final solution (Table I).However, blank solutions containing reagent concentrations higher than 0.4mgml-l are dark in colour. The use of a 2.0-ml volume of 0.5% PDAC solution was considered satisfactory for the drug concentration levels proposed in this assay.September, 1983 SHORT PAPERS TABLE I 1147 EFFECT OF p-DIMETHYLAMINOCINNAMALDEHYDE (PDAC) CONCENTRATION ON COLOUR INTENSITY Volume of 0.5% PDAC solution/ ml 0.5 1.0 1.5 2.0 2.5 3.0 Absorbance* at Amax.t Phenylbutazone Oxyphenbutazone Sulfinpyrazone 0.180 0.094 0.168 0.355 0.192 0.330 0.630 0.262 0.589 0.660 0.338 0.610 0.742 0.427 0.694 1.125 0.431 1.051 A I \ * Concentration of the drug in the final assay solution, 5.0 pg ml-l. t Amax. : phenylbutazone and sulfinpyrazone, 540 nm ; oxyphenbutazone, 525 nm.The colour in all instances reached maximum intensity after 15 min and was stable for a t least 24 h. Beer’s law was obeyed for up to 7 pg ml-l of PB, up to 15 pg ml-l of OPB and up to 8 pg ml-l of SP in the final test solution. The reproducibility of the procedure was determined by running replicate samples, each containing 5 pg ml-1 of PB in the final test solution. At this concentration level, the relative standard deviation for five determinations was 0.44%. Results of determinations of PB, OPB and SP in bulk materials, pharmaceutical preparations and synthetic mixtures are in good agreement with those of the BP 1980 method (Table 11). The data in Table I1 show that the ingredients commonly found with pyrazolidinedione derivatives in antirheumatic, analgesic and anti-inflammatory formulations, such as amido- pyrine, aluminium hydroxide, aspirin, Novalgin and ascorbic acid, which interfere in the official BP method, do not interfere in the proposed spectrophotometric method.TABLE I1 DETERMINATION OF PYRAZOLIDINEDIONE DERIVATIVES IN BULK MATERIALS, IN PHARMACEUTICAL PREPARATIONS AND IN SYNTHETIC MIXTURES Sample Phenylbutazone . . .. .. Oxyphenbutazone . . .. .. Sulfinpyrazone . . . . . . Phenylbutazone tablet . . . . Curazolidine tablet . . . . .. Curapyrine tablet . . . . .. Curazolidine ampoule . . . . Oxyzone tablet . . * . . . Tanderil tablet . . .. .. Rhumaxin tablet . . . . Phenylbutazone -t Al(0H);’ . . Phenylbutazone + ascorbic acid . . Phenylbutazone + Novalgin . . Phenylbutazone + aspirin. . . . * Average of three determinations. 7 N.a., not applicable. .. .. . . .. .. .. . . .. .. .. .. * . . . .. Label claim 100 mg of PB 200 mg of P B 125 mg of PB + 125 mg 20% m/V PB 100 mg of OPB 100 mg of OPB 100 mg of OPB of amidopyrine Found,* yo Proposed BP 1980 method method 99.4 99.6 100.1 99.4 98.8 99.1 99.7 100.2 99.9 100.7 100.3 97.8 97.0 99.7 99.2 100.2 99.6 98.9 100.0 N.a.t 98.3 96.4 99.1 98.8 N.a. N.a. N.a. N.a. References 1. 2. 3. “British Pharmacopoeia 1980,” HM Stationery Office, London, 1980, pp. 322, 345 and 439. Rose, J ., “Advanced Physico-Chemical Experiments,” Pitman Press, London, 1964, p. 54. March, J ., “Advanced Organic Chemistry : Reactions, Mechanisms and Structure,” Second Edition, Received Mu& loth, 1983 Accepted April 12th, 2983 McGraw-Hill, Kogakusha Ltd., Tokyo, 1977, p. 106.

ISSN:0003-2654    

DOI:10.1039/AN9830801144

出版商:RSC    

年代:1983

数据来源: RSC

摘要:

1148 SHORT PAPERS Analyst, Vol. 108 Selective Complexometric Method for Palladium Determination in Alloys Using Thiocyanate as Releasing Agent Krishna Narayan Raoot, Sarala Raoot and V. Lalita Kumari Defence Metallurgical Research Laboratory, P.O. Kanchanbagh, Hyderabad-500 258, India Keywords : Palladium determination ; selective complexometry ; thiocyanate release ; metal alloys Owing to poor selectivity, earlier complexometric methodP6 for palladium could not be used for its determination in its alloys with copper, nickel or rare earths because these metals also form strong complexes with ethylenediaminetetraacetic acid (EDTA). Thus, it was desirable to evolve selective masking or releasing agents for palladium. In previous work, dimethylgly~xime,~ 1,2,3-benzotriazole,8 1,lO-orthophenanthroline,g thiourealo and pyridinell have been suggested as releasing agents for palladium in the presence of common metal ions.In this work the use of thiocyanate for the selective decomposition of the palladium - EDTA complex at a pH of 5-5.5 at room temperature is described. The liberated EDTA is then titrated against standard lead( 11) nitrate solution with xylenol orange as an indicator. Experimental Reagents and Apparatus A stock solution of palladium was prepared by dissolving 1 g of palladium(I1) chloride (Johnson Matthey) in the minimum volume of concentrated hydrochloric acid and diluting to 11. The solution, on gravimetric standardisation with ascorbic acid,12 was found to contain 0.60 mg ml-1 of palladium. EDTA (0.01 M), lead(I1) nitrate (0.01 M), xylenol orange (0.1%) and ammonium thiocyanate (10%) solutions were prepared from their respective analytical-reagent grade reagents (BDH Chemicals Ltd.).Sodium acetate - acetic acid buffer was prepared in the usual way. Suitable salts of various metal ions were used to make up their solutions. A Metrohm Harrisau, Model EA 121, pH meter with combined glass electrodes was used for pH measurements. All chemicals used were of analytical-reagent grade. Procedure Determination of palladium in the presence of other cations To a solution containing 3 4 2 mg of palladium and varying amounts of diverse ions, add an excess of 0.01 M EDTA and dilute the solution to 70-80 ml. Adjust the pH initially to between 4 and 5 with the dropwise addition of dilute sodium hydroxide solution and finally to 6-5.5 with the addition of sodium acetate - acetic acid buffer.Add a few drops of xylenol orange indicator and back-titrate the excess of EDTA with 0.01 M lead(I1) nitrate solution to the sharp colour change from yellow to red. To the titrated solution, add 2-12 ml of 10% ammonium thiocyanate solution (100 nig of the reagent for each 6 mg of palladium), shake and titrate the liberated EDTA with 0.01 M lead(I1) nitrate solution to the same end-point as in the first titration. Application to alloys Dissolve 0.1-0.2 g of the sample in the minimum amount of aqua regia and dilute to 100 ml in a standard calibrated flask. Add an excess of 0.01 M EDTA and dilute the solution to 70-80 mi with distilled water. Adjust the pH of the solution to 5-5.5 and perform the determination of palladium as described.Transfer a suitable aliquot into a 250-ml conical flask.Se$tember , 1983 SHORT PAPERS 1149 Results and Discussion The stability constant of the palladium(I1) - EDTA chelate is reported12 to be 26.4. Although thiocyanate is used for the spectrophotometric determination of palladium,l3 no data on the stability constant of the palladium - thiocyanate complex are given in the litera- ture. These findings show that palladium(I1) forms a more stable complex with thiocyanate than with EDTA and the reverse is true with common metal ions.14 It is because of these facts that the release of EDTA from the palladium complex is selective. Besides ammonium thiocyanate , potassium thiocyanate and sodium thiocyanate were also examined for the masking of palladium and were found to be equally satisfactory. A few results obtained with these reagents are incorporated in Table I.The decomposition of the palladium(I1) - EDTA complex with thiocyanate was found to be quantitative at a pH of 5-5.5 even at a temperature as low as 8 "C. A 1-ml volume of 10% thiocyanate solution caused a quantitative release of EDTA from 6 mg of palladium, leaving a clear solution; when added in smaller amounts a precipitate was formed. Table I shows that copper(I1) zinc(II), nickel(II), cobalt(II), cadmium(I1) lead(I1) , bismuth(III), iron(II1) , aluminium(II1) , rhodium(II1) ruthenium(II1) , platinum(IV), TABLE I DETERMINATION OF PALLADIUM IN THE PRESENCE OF FOREIGN METAL IONS Amount of palladiumlmg Amount of foreign ,--*------, Foreign ion Cu(I1) .. Zn(I1) . . Ni(I1) . . Co(I1) . . Cd(I1) . . Pb(I1) . . Mn(I1) Bi(II1). . Fe( 111) Al(II1). . Ti(1V) . . V(1V) .. La( 111) Ce( 111) Sm(II1) Ho(II1) Pt(1V) . . Rh (I 11) Ru (111) Os( VIII) . . .. . . .. .. .. . . . . .. .. .. .. .. .. .. .. . . .. .. .. .. . . .. . . . . . . .. .. .. .. .. .. .. .. .. f . .. .. .. .. u ion/mg 12.00 24.00 25.00 10.00 19.80 9.90 20.00 10.00 15.00 10.00 25.50 12.75 5.00 3.00 5.00 20.00 20.00 5.00 20.00 5.00 18.00 12.00 10.00 30.00 15.80 7.90 20.40 10.20 33.90 11.30 25.50 12.25 16.00 8.00 9.20 18.40 11.80 5.90 6.00 12.00 Taken 24.00 6.00 6.00 42.00 3.00 18.00 9.00 12.00 9.00 30.00 3.00 18.00 15.00 12.00 15.00 24.00 9.00 30.00 6.00 15.00 12.00 24.00 36.00 9.00 3.00 42.00 6.00 36.00 3.00 42.00 6.00 15.00 3.00 12.00 9.00 6.00 6.00 18.00 15.00 6.00 Found 24.05 5.96 6.01 41.97 2.98 18.03* 9.03 11.97 8.98 29.95 2.981.17.98 15.12 12.08 14.95 24.11* 9.03 29.95 5.96 15.00 11.97t 23.94 35.96 9.03 3.03 41.92* 6.01 36.067 2.98 42.08 6.01* 14.95 2.98 11.97 8.98 5.96 6.01 17.93 14.95t 5.96 Error, yo +0.21 -0.67 +0.17 -0.07 -0.67 +0.17 + 0.33 - 0.25 -0.22 -0.17 - 0.67 -0.11 +0.80 +0.67 - 0.33 + 0.46 +0.33 -0.17 -0.67 0.00 -0.25 - 0.25 -0.11 +0.33 + 1.00 -0.19 f0.17 + 0.17 + 0.19 +0.17 -0.33 - 0.67 -0.25 -0.22 -0.67 +0.17 -0.39 -0.33 - 0.67 -0.67 * Potassium thiocyanate was used as masking agent. t Sodium thiocyanate was used as masking agent.1150 SHORT PAPERS Analyst, Vol. 108 titanium(IV), vanadium(IV), osmium(VII1) and rare earths do not have any adverse effect on this titration. Mercury(II), iridium( 111) and tin(IV), however, interfere seriously.Manganese(II), owing to the low stability of its EDTA complex under the conditions employed, caused some difficulty in the end-point detection, particularly when more than 5 mg of it were present. An amount of palladium ranging from 3 to 42 mg could be deter- mined in the presence of varying amounts of different foreign metal ions by this method with an error not exceeding 1.0%. The standard deviations calculated, based on eleven values each for 3, 24 and 42 mg, were 0.05, 0.06 and 0.08 mg, respectively. Results for synthetic solutions and alloy samples, given in Table 11, show that the values obtained by this method are in good agreement with those obtained by gravimetric methods using ascorbic acidl5 and hydroxylammonium chloride.16 TABLE I1 DETERMINATION OF PALLADIUM IN SYNTHETIC SOLUTIONS AND IN SOLID ALLOY SAMPLES Palladium/mg Alloy* Taken 35% CU-Pd ... . 20.50 43% Cu-Pd$ . . . . 21.40 39% Sm-Pd§ . . . . 22.90 64% Sm-Pd$ . . . . 21.60 40% Ni-Pd .. . . 24.00 39% Ni-Pd$ .. . . 30.50 36% CO-Pd .. . . 25.60 Found7 ' 20.54 20.50'; 21.39 21.427 22.93 22.85'; 21.55 21.60'; 23.99 24.057 30.48 30.457 25.64 25.657 * Simulated sample unless otherwise mentioned. t Mean of two determinations. § Solid sample. 7 By gravimetric method using hydroxylammonium chloride. By ascorbic acid gravimetric method. The proposed method is superior to previous methods in that previously used reagents either yielded precipitates on the release of EDTA, which limits the amount of palladium that can be determined, or had interferences from a number of cations.Additionally, the majority of them required the solutions to be heated for the complete release of EDTA. Thiocyanate, however, yields a soluble complex when larger amounts of palladium are present, releases EDTA instantaneously in cold solution and can tolerate a larger number of cations. We thank Dr. P. Rama Rao, Director, Defence Metallurgical Research Laboratory, Hyderabad, for his permission to publish this paper. 1. 2. 3. 4. 6. 6. 7. 8. 9. 10. 11. References McNevin, W. M., and Kriege, O., Anal. Chem., 1955, 27, 535. Kinnunen, J., and Merikanto, B., Chemist-Analyst, 1955, 44, 11. Suk, V., and Malat, M., Chemist-Analyst, 1956, 45, 30. Kinnunen, J., and Merikanto, B., Chemist-Analyst, 1958, 47, 11. Khalifa, H., and Khater, M. M., 2. Anal. Chem., 1962, 191, 339. Yurist, I. M., and Tynkova, 2. V., Zavod. Lab., 1962, 28, 798. Raoot, K. N., and Raoot, S., Indian J . Chem., 1974, 12A, 1007. Raoot, K. N., Raoot, S., and Vaidya, V. G., Indian J . Chem., 1979, 18A, 90. Raoot, S., and Raoot, K. N., Indian J . Technol., 1980, 18, 345. Raoot, K. N., and Raoot, S., Talanta, 1981, 28, 327. Raoot, S., Raoot, K. N., and Lalita Kumari, V., Analyst, 1982, 107, 1382.Se?tember, 1983 SHORT PAPERS 1151 Kragten, J., Talanta, 1978, 25, 239. Kodama, K., “Methods of Quantitative Inorganic Analysis,” Interscience, New York, 1963, p. 246. Lurie, Yu., “Handbook of Analytical Chemistry,” Mir, Moscow, 1975, p. 288. Ripan, R., and Pop, G., Rev. Roum. Chim., 1967, 12, 13. Raoot, S., and Vaidya, V. G., J . Chin. Chem. SOC. (Taipei), 1979, 26, 181. 12. 13. 14. 15. 16. Received March 2nd, 1983 Accepted April l l t h , 1983

ISSN:0003-2654    

DOI:10.1039/AN9830801148

出版商:RSC    

年代:1983

数据来源: RSC

摘要:

Se?tember, 1983 SHORT PAPERS 1151 Spectrophotometric Determination of Rhodium( Ill) in Thermocouple Wires Using Thiocyanate and Rhodamine 6G Sambamoorthy Jaya," Talasila Prasada Rao and Tiruvesaloor Venkatarama Ramakrishna Defiartment of Chemistry, Indian Institute of Technology, Madras-600 036, India Keywords : Rhodium determination ; spectrophotometry ; thiocyanate ; Rhodamine 6G ; thermocouple wives Recently, a method has been described for the spectrophotometric determination of rhodium, which exploits the interaction of its tin(I1) chloride complex with malachite green in hydro- chloric acid medium.l The resulting ion pair was floated by equilibrating with benzene or diisopropyl ether and photometric measurements were made after dissolving the precipitate in 3% acetone - water.Although more sensitive (molar absorptivity, €benzene = 1.44 X lo5 and €ether = 3.4 x lo5 1 mol-l cm-l) than those involving the reaction with Eriochrome Cyanine R and cetylpyridinium bromide (E = 1.2 x lo4 1 mol-l cm-1)2 and tin(I1) bromide and diantipyrinylmethane (E = 3.9 x lo4 1 mol-1 cm-1)3 the procedure lacks adequate selec- tivity and many factors, particularly in the ether-based procedure, must be controlled to obtain reproducible results. Further, the applicability of this procedure to the analysis of real samples has not yet been reported. In this work, it was found that the ion-association complex involving rhodium(III), thio- cyanate and Rhodamine 6G can be stabilised in aqueous media by the addition of gelatin, thus providing a basis for a highly sensitive ( E = 1.3 x lo5 1 mol-l cm-l) spectrophotometric method for rhodium. Several of the interferences encountered were conveniently overcome by masking and simple preliminary treatment.The method is rapid and reliable and is useful for the determination of rhodium in thermocouple wires. Experimental Reagents chloric acid. hydrochloric acid. Chemicals, AnalaR grade) in water and dilute to 100 ml with water. in water and dilute to 1 1 with water. water and dilute to 100 ml with water. glacial acetic acid and adjust the pH to 4.0. Rhodium solution, 1000 pg ml-l. Dissolve 1.366 g of RhC1,.4H20 in 500 ml of 1 N hydro- Prepare a 5 pg ml-1 solution by diluting this stock solution suitably with 1 N Potassium thiocyanate solution, 5:4, m/V. Dissolve 5 g of potassium thiocyanate (BDH Rhodamine 6G solution, 0.00570 m/V.Dissolve 0.05 g of Rhodamine 6G (BDH Chemicals) Thiourea solution, 10% m/V. Dissolve 10 g of thiourea (BDH Chemicals, AnalaR grade) in Bu,,er solution. Prepare by mixing an appropriate volume of 1 M sodium acetate with GeZatin solution, 1% m/V. Dissolve 1 g of gelatin in hot water. Cool and dilute to 100 ml. * Present address : Electroanalytical Division, Central Electrochemical Research Institute, Karaikudi-623 006, India.1152 SHORT PAPERS Analyst, Vol. 108 Apparatus A Carl Zeiss PMQ-I1 spectrophotometer was used for measuring absorbances in 40-mm quartz cells. Procedure Transfer a suitable aliquot (up to 10 ml) of the sample solution containing not more than 5 pg of rhodium into a 50-ml beaker, add 2.5 ml each of the buffer and potassium thiocyanate solutions and heat for 20 min on a boiling water-bath.Transfer the cooled solution into a 25-ml calibrated flask and add, with mixing, 5 ml of Rhodamine 6G followed by 1 ml of gelatin solution. Add 1 ml of thiourea solution and dilute to volume with distilled water and measure the absorbance in 40-mm cells at 565 nm against a reagent blank . Establish the concentra- tion by reference to a calibration graph prepared for 0.5-5 pg of rhodium. Results and Discussion Spectral Characteristics and Reaction Conditions During the systematic investigation of the colour reaction, it was observed that the complex formed initially after heating the rhodium and thiocyanate solution produced a pink coloration almost at once upon the addition of Rhodamine 6G, whereas the one that was formed in cold solution reacted slowly, the colour development being incomplete even after standing for 1 h at room temperature.The pink coloration, developed in the former instance, began to fade gradually on standing, owing to the precipitation of the ion associate. However, it was found that this could be prevented by the addition of gelatin. The best results were obtained when gelatin was added after the addition of Rhodamine 6G solution. The examination of the spectra (Fig. 1) showed that in the presence of rhodium, the absorption maximum of the dye at 530 nm shifts to 565 nm, the intensity of which increased in direct proportion to the concentra- tion of rhodium present. Two sets of experiments were carried out to establish the influence of pH on colour develop- ment.In one, the binary complex was formed by reacting rhodium and thiocyanate at different pHs (pH 1-9) before associating with Rhodamine 6G at pH 4. In the other, the binary complex was formed at pH 4 and then allowed to interact with Rhodamine 6G at various pHs. The results are shown in Fig. 2, from which it is evident that the interaction 0.8 0 400 500 600 700 Wavelengthhrn Fig. 1. Absorption spectra (10-mm cells; reference, water) for A, 3 ml of 1.07 x M (0.00570) Rhodamine 6G, 2.5ml each of 5% potassium thiocyanate and pH 4 buffer, 1 ml of 1% gelatin and final volume 25 ml; and B, C and D, as in A with 1, 2.5 and 5 ml of 1.943 x 10-5 M (20 pg ml-1) rhodium(II1).September, 1983 SHORT PAPERS 1153 proceeds most favourably over the pH range 3-5.A pH 4 buffer solution was maintained by using 1 M acetate buffer. With other variables held constant, as evident from Fig. 3, it was found that for a constant and maximum absorbance a minimum of 2 ml of a 2.5% solution of potassium thiocyanate (A) and 4.5 ml of o.oo5~0 Rhodamine 6G (B) were necessary. Although the addition of an excess of dye did not affect the sensitivity, it should be avoided as the absorbance of the blank (0.10 5 0.01) for 5 ml was found to increase with increasing concentra- tion of Rhodamine 6G in the medium. It was also found that 1 ml of 1% gelatin was sufficient to prevent the precipitation of the ion association complex and that it should be added after the addition of Rhodamine 6G for maximum colour development.The ternary complex was found to be stable for 24 h. The effect of temperature on the formation of rhodium thiocyanate wasestablished by heating the mixture for 30 min at different temperatures ranging from 40 to 98 "C in a thermostat. Measurement of absorbance, after colour development, showed a constant and maximum absorbance for solutions that were left at 80 "C and above. Further studies disclosed that similar results could be obtained by heating the mixture on a boiling water-bath for 15 min and that prolonged heating for up to 40 min does not affect the results. 0.4 a) C lu a & 0.2 2 - . B al C m n $ 0.2 - A 1 1 1 . a I I 0 4 8 I I I I Volume of (A) KSCN or (B) Rhodamine 6G/ml 0 4 8 PH Fig. 2. Effect of pH on colour develop- ment for A, formation of Rh - SCN- com- plex; and B, interaction of Rh - SCN- complex with Rhodamine 6G.Conditions were as follows: 2 pg of rhodium; 2.5 ml of 5% potassium thiocyanate; 5 ml of 0 . 0 0 5 ~ 0 Rhodamine 6G; 1 ml of 1% gelatin; final volume, 25 ml; wavelength, 565 nm; and 40-mm cells. Fig. 3. Effect of potassium thio- cyanate and Rhodamine 6G on colour development for A, 5 ml of 0.005% Khodamine 6G and xml of thio- cyanate; and B, 2.5 ml of 5% potassium thiocyanate and x ml of Rhodamine 6G. Conditions were as follows: 2 pg of rhodium; 2.5 ml of pH 4 buffer; 1 ml of 1% gelatin; final volume 25 ml; wavelength, 565 nm; and 40-mm cells. Calibration Graph and Precision 0-5 pg of rhodium in a final volume of 25 ml. 1.3 x lo5 1 mol-l cm-l.was found to be 0.5% for ten replicate determinations. The calibration graph obtained by the recommended procedure was linear over the range The molar absorptivity was calculated to be The coefficient of variation for the determination of 1 pg per 25 ml Stoicheiometry The composition of the ternary complex was established to be rhodium : thiocyanate : Rhodamine 6G = 1 : 6 : 3. Molar ratio and continuous variation methods were used to establish the rhodium to Rhodamine 6G ratio and the equilibrium shift method was used to establish the rhodium to thiocyanate ratio. Interference Studies The examination of 500-fold amounts of several cations and anions for the determination of 2 pg of rhodium revealed that Ca, Sr, Ba, Mg, Be, Pb(II), Cd, Fe(II), Mn(II), Ni, U(VI), Cr(III),1154 SHORT PAPERS Analyst, Vol.108 As(III), Al, Bi, La(III), Tl(III), Th(1V) , Ce(IV), Se(IV), Sb(V), As(V), Br-, NO,-, ClO,-, B,0,2- and Po,3- do not interfere (the criterion for no interference is 0.40 3%). However, 500-fold amounts of Fe(III), Zr(1V) and W(V1) interfered but were overcome by the addition of 1 ml of 5% sodium fluoride. Interference due to similar amounts of zinc and molybdenum- (VI) was eliminated by the addition of 1 ml of 5% sodium hexametaphosphate. Addition of thiourea after the addition of Rhodamine 6G destroyed similar ternary ion associates formed with 400-fold amounts of Pt(IV), Pd(II), Cu(II), Hg(I1) and Co(I1). Os(VII1) and Ru(II1) interfered seriously but were overcome by boiling the sample with 1 ml of 1% potassium permanganate4 and destroying the excess of the latter with 1 ml of 5% ascorbic acid, before colour development.No interference was encountered from the presence of %-fold amounts of Ir(1V). TABLE I ANALYSIS OF SYNTHETIC SAMPLES Rhodium concentration = 2 p g in 25 ml. Other constituent/mg Absorbance None .. . . .. .. 0.40 Pt (0.8) + Pd (0.8) +‘Ir (0.05) . . .. .. 0.40 Pt (0.8) + Fe (1) + Pb (1) . . .. .. .. 0.41 Pt (0.8) + Ru (1) + 0s (l)*. . .. .. .. 0.39 U (1) + Ni (1) + Zr (1) . . .. .. .. 0.41 La (1) + Ti (1) + U (1) . . . . .. .. 0.39 * After distillation as tetroxides. Analysis of Synthetic Samples and Thermocouple Wires Table I presents the results of the analysis of synthetic sample solutions after overcoming the influence of the interferents as described under Interference Studies.Table I1 gives the results of the analysis of 10% rhodium - platinum and platinum thermo- couple wires by the proposed method. The recoveries obtained by adding known amounts of TABLE I1 ANALYSIS OF 10% RHODIUM - PLATINUM AND PLATINUM THERMOCOUPLE WIRES Sample/ Rhodium added, Rhodium found, Q per 250 ml % by mass % by mass Recovery, % Platinum wiye- - - - 0.0502 0.0500 0.05 0.05 100 0.0488 0.50 0.50 100 0.0550 1.00 1.01 101 10% Rh - Pt alloy wiye*- 0.0500 - 10 - 0.0498 1.00 11.02 102 0.0515 2.43 12.38 98 0.0462 5.41 15.41 100 * Stock solution diluted 20-fold and 2-ml aliquots subjected t o determination. rhodium(II1) solution to both the platinum and the rhodium - platinum alloy wire are also given. The samples were brought into solution, by repeated attack with aqua regia as described elsewhere,5 and diluted to 250 ml. Determinations were made by subjecting suitable aliquots to colour development. The results suggest that the method can be reliably applied to the determination of rhodium alloyed to various metals. One of the authors (S. J.) is grateful to C.S.I.R., New Delhi for financial assistance.September, 1983 SHORT PAPERS 1155 References 1. 2. 3. 4. 5. Marczenko, Z., and Kowalczyk, E., Anal. Chim. Acta, 1979, 108, 261. Duchkova, H., Cermakova, L., and Malat, M., Anal. Lett., 1975, 8, 115. Pilipenko, A. T., Danilova, V. N., and Lisichenok, S . L., Zh. Anal. Khim., 1970, 25, 1154. Sandell, E. B., “Colorimetric Determination of Traces of Metals,” Third Edition, Interscience, New Furman, N. H., “Standard Methods of Chemical Analysis,” Van Nostrand, New York, 1962, p. 899. Received March 18th, 1983 Accepted April 24th, 1983 York, 1959, p. 705.

ISSN:0003-2654    

DOI:10.1039/AN9830801151

出版商:RSC    

年代:1983

数据来源: RSC

摘要:

September, 1983 SHORT PAPERS 1155 Solvent Extraction Studies of Thorium( IV) with Aliquat 336 as an Extractant Miss Mangal R. Shivade and Vijay M. Shinde Analytical Laboratory, Department of Chemistry, Shivaji University, Kolhapur, 4 16 004, India Keywords : Tlwriurn(I V ) solvent extraction; Aliquat 336 The isotopes of thorium, especially 232Th, find application in nuclear fuels. Thorium is also used in dissipating static electricity and in the gas mantle industry. Solvent extraction methods for thorium(1V) are reviewed by De et a1.l and Korkisch2 in their monographs. In most of the previous methods, extractants such as tributyl ph~sphate,~ Aliquat 336, Hyamine 1 662,4 trioctylphosphine oxide,5 diphenyl sulphoxide6 and mesityl oxide7 have been used for the extraction of thorium(1V).However, these methods suffer from drawbacks such as time consumption, the use of a salting-out agent and the use of an excess of extractant. The extraction of thorium with a mixture of thenoyltrifluoroacetone and tributyl phosphate8 and high relative molecular mass carboxylic acidsg is also reported. However, these methods have few practical applications. This investigation was undertaken to evaluate and select a solvent extraction procedure for the quantitative extraction and separation of thorium from some of the elements. The ultimate achievement is a rapid, selective and simple method for the extraction and subsequent determination of thorium. The proposed method describes the scheme for the separation of thorium(1V) from associated metal ions such as lanthanum(III), neodymium(II1) and uranium(V1) from binary mixtures and from various metallic series from multi-component mixtures.Experimental Apparatus and Reagents quartz cells and pH was measured on a Philips Precision pH meter. Absorbance measurements were made on a Zeiss spectrophotometer (Jena) using 1-cm All chemicals were of guaranteed grade, unless indicated otherwise. Thorium(1V) stock solution. This was prepared by dissolving 6.34 g of thorium nitrate (analytical-reagent grade) in 0.1 M nitric acid. This solution was diluted to 500 ml, standard- ised by a known methodlo and diluted further as required to give a working solution. A 1 yo nz/V solution of Aliquat 336 (tricaprylmonomethylammonium chloride) (Koch-Light) in benzene was prepared; equilibrated for 30 min with equal volumes of 2 M sodium succinate solution and used for the extraction of thorium(1V).Caution-Benzene is highly toxic and appropriate precautions should be taken. Extracting solution. Extraction Procedure for Thorium( IV) An aliquot of a solution containing 1 mg of thorium(1V) was mixed with 0.5-0.67 g of sodium succinate (0.075-0.1 M) in a total volume of 25 ml. The pH of this solution was adjusted to 7-8 with dilute nitric acid and sodium hydroxide solution. This solution was then transferred into a 1.00-ml separating funnel and equilibrated for 5 min with 2 x 5 ml of 1% Aliquat dissolved in benzene. The two layers were separated, the aqueous phase was dis- carded and metal ion was back-extracted from the organic phase with 10 ml of 0.1 M nitric1156 SHORT PAPERS Analyst, Vol.108 acid solution. This aqueous extract was equilibrated with benzene to remove trace amounts of dissolved Aliquat, and finally thorium was determined titrimetrically with EDTA using xylenol orange as an indicator.1° Results and Discussion The extraction of thorium(1V) was investigated at various pH values (4-13) and sodium succinate concentrations (0.01-0.2 M) (Fig. 1). The optimum pH range for the quantitative extraction of thorium(1V) with Aliquat 336 was 7-8. Similarly, the quantitative extraction of thorium(1V) was achieved from 0.075 to 0.1 M sodium succinate solution when extracted with 1 yo Aliquat solution in benzene. The variation in Aliquat concentration using benzene as diluent showed that a 1% solution of Aliquat was adequate for the quantitative extraction of thorium(1V).The most effective stripping agent was 0.1 M nitric acid solution, which com- pletely removed the metal ion from the organic phase. The percentage extraction and distribution ratios were calculated after stripping the metal ion from the amine phase and subsequent titrimetric determination as described under Extraction Procedure, The log - log plot of the distribution ratio veysus Aliquat concentration at a fixed succinate concentra- tion gave a slope of 2 indicating a metal to amine ratio in the extracted species of 1:2. Similarly, a log - log plot of the distribution ratio versus sodium succinate concentration at fixed pH and amine concentration gave a slope of nearly 2, indicating a metal to succinate ratio of 1 : 2 in the extracted species.100 #? 80 i ti 60 2 .- c w 40 0 0.08 0.16 0.24 Sodium succinate concentration/M Fig. 1. Extraction be- haviour of thorium(1V) as a function of sodium succinate concentration. Effect of Diverse Ions Various amounts of foreign ions were added to a solution containing fixed amounts of thorium(1V) and sodium succinate. The recommended procedure was then followed for the extraction and determination of the metal ion. The results showed that in the extraction and determination of 1 mg of thorium(IV), 15 mg of sulphate, 10mg each of Ni(II), Hg(II), carbonate and thiourea, 7.5mg of Co(II), 5mg each of Cr(VI), Zn(II), Cd(II), La(III), Ce(IV), Gd(III), Br-, I-, F- and ascorbate, 3 mg each of W(VI), Ag(I), Au(III), Y(II1) and nitrate, 2 mg each of Ru(III), Pr(II1) and Nd(II1) and 1 mg each of Cu(II), Pd(II), U(V1) and Os(VII1) did not interfere.However, 1 mg each of V(V), Pt(IV), Fe(III), Sc(III), Sm(III), thiocyanate and EDTA interfered severely and must be absent. Separation of Thorium( IV) from Lanthanum( 111) The extraction of thorium( IV) into Aliquat 336 by the recommended procedure facilitates its separation from lanthanum(II1) in the binary mixture, as lanthanum does not extract into Aliquat 336 and remains completely in the aqueous phase. In the aqueous phase lanthanum (I I I) is determined with Arsenazo I l1 spect rop ho t ome tricall y. The extracted thorium( IV) from the organic phase is subsequently determined as described under Extraction Procedure. The results of the separation are reported in Table I.September, 1983 SHORT PAPERS 1157 TABLE I ANALYSIS OF SYNTHETIC MIXTURES All analyses were carried out in triplicate.Composition of synthetic mixture and amounts taken/mg l T h , 5La . . . . . . . . . . l T h , l U .. . . . . .. . . 1Th. 1Nd .. .. .. .. 1 Th, 2.5 Au, 2.5 Ag, 5 Ni, 1 Cu 1 Th, 1 Cu. 5 Co, 5 Ni . . . I .. 1 Th, 1 Pd, 1 0 s . . .. .. .. 1 Th, 5 Zn, 5 Cd, 2.5 Hg . . .. . . . . . . Recovery of thorium( IV) , 99.4 99.4 99.4 99.4 99.4 98.6 98.6 % Recovery of Relative error Relative error, added ion, of added ion, % % % 0.6 100 0 0.6 99.42 0.58 0.6 99.43 0.57 0.6 0.6 1.4 1.4 - - - - - - - - Separation of Thorium( IV) from Uranium(V1) and Neodymium( 111) Both uranium(V1) and neodymium(II1) show co-extraction with thorium(IV), when extracted with 1% Aliquat from 0.1 M sodium succinate solution.Their separation is, how- ever, performed by selective scrubbing of uranium(V1) with water and neodymium(II1) with 0.1 M perchloric acid. In the back-extracted portion uranium(V1) and neodymium(II1) are determined spectrophotometrically with 4-(2-pyridylazo)re~orcinol.~~~~~ Thorium(1V) was subsequently stripped and determined as described under the recommended procedure. The recovery of metal ions was found to be greater than 98%. The results of the separation are reported in Table I. Separation of Thorium( IV) from Multi-component Mixtures Multi-component mixtures containing different metal ions of the same series were taken with thorium(1V) and the extraction procedure was followed.Thorium(1V) from the organic phase was selectively back-extracted and determined titrimetrically as described under Extraction Procedure. The recovery of thorium(1V) was found to be greater than 98%. The results of the separation are given in Table I. The results in Table I1 show that the method has a high degree of precision with a standard deviation of 0.12 ml and coefficient of variation of 1.40%. TABLE I1 PRECISION DATA FOR THE DETERMINATION OF THORIUM(IV) Concentration of Mean titration reading of Standard Coefficient of Th/mg ml-1 6 determinationslml deviation/ml variation, yo 1 8.45 0.12 1.40 The authors thank the Department of Atomic Energy, Bombay, for awarding a fellowship to one of them (M.R.S.). 1. 2. 3. 4. 5 . 6. 7. 8 . 9. 10. 11. 12. 13. References De, A. K., Khopkar, S. M., and Chalmers, R. A., “Solvent Extraction of Metals,” Van Nostrand Korkisch, J., “Modern Methods for Separation of Rare Metal Ions,” Pergamon Press, New York, Chen, Chang-Chyuan, and Ting Gann, J . Chin. Chem. SOC. (Taipei), 1977, 24, 26. Bhandiwad, V. R., Swarup, R., and Patil, S. K., J . Radioanal. Chem., 1979, 5, 52. Guyon, C. J.. and Madison, B., Mikrochim. Acta, 1975, 1, 133. Reddy, A. S., and Reddy, L. K., Sep. Sci., 1977, 12, 641. Chun-Hwa, Jen, and Mei Cheng Chen, Hua Hsueh, 1968, 4, 148. Patil, S. K., Ramkrishna, V. V., Sajun, M. S., and Thiagarajan, R. L., J . Radioanal. Chem., 1979, De, A. K., J . Indian Chem. Soc., 1975, 51, 195. Vogel, A. I., “A Text Rook of Quantitative Inorganic Analysis,” Longmans, London, 1961, p. 442. Shibata, S., Takruchi, F., and Matsumae, T., Anal. Chim. Acta, 1959, 21, 177. Busev, A. I., and Ivanov, V. M., Vestn. Moskov. Univ. Sev. Khim., 1969, 3, 52. Munshi, K. N., and De, A. K., Anal. Chem., 1964, 36, 2003. London, 1970. 1969. 54, 159. Received January 5th, 1983 Accepted March 22nd, 1983

ISSN:0003-2654    

DOI:10.1039/AN9830801155

出版商:RSC    

年代:1983

数据来源: RSC

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1158 Analyst, September, 1983 Communications Material f o r publication as a Communication must be on a n urgent matter and be of obvious scientific importance. Rapidity of publication i s enhanced i f diagrams are omitted, but tables and formulae can be included. Communications should not be simple claims f o r Priority; this facility for rapid publication i s intended for brief descriptions of work that has progressed to a stage at which it i s likely to be valuable to workers faced with similar problems. A fuller paper may be offered subsequently, i f justijied by later work. Simple Modification to a Commercially Available Atomic Vapour Accessory to Reduce Memory Effects when Determining High Levels of Arsenic in Geological Materials Keywords : Arsenic determination ; geological materials ; hydride generation technique ; atomic-absorption spectrometry The determination of arsenic by generation of its hydride and subsequent atomisation in a flame or electrothermal cell is a well established atomic-absorption spectrometric technique.This paper concerns the problems encountered in determining arsenic in stream sediment samples using a commercially available closed quartz atom cell heated by an air - acetylene flame, and outlines the measures taken to eliminate them. The equipment used, an Instrumentation Laboratory atomic vapour accessory (AVA 440), consists of a vapour generator and quartz atom cell with optical quartz end windows and entrance and exit side-arms at opposite ends of the tube. The cell is clamped in an integral holder and air - acetylene burner head.All measurements were made with an Instrumentation Laboratory IL 951 atomic-absorption spectrophotometer in the background-corrected mode a t the arsenic 193.7-nm wavelength. Acceptable calibration graphs could be prepared from 0 to 250 ng of arsenic (equivalent to 0 to 50 p g g-l of arsenic in the samples) provided the standards were run in ascending order of concentration. When samples with extremely variable concentrations of arsenic were analysed, an acute carry- over problem emerged. Blanks run after each sample were erratic, giving arsenic values equivalent to 15-25% of the concentration of the previous sample and with very high samples as much as 40%. A succession of blanks run after a sample did not always produce a pattern of decreasing values and a succeeding sample could give an arsenic value lower than the preceding blank.It was suspected that the quartz tube was porous, so new tubes were obtained. These showed slightly different characteristics but the main problem remained. During this investigation it was found that an effective method of cleaning the tubes and re-activating the interior quartz surface was to use a 15-min soak in 5% hydrofluoric acid,l followed by a 5-min boil in concentrated nitric acid.2 Evans et aL3 and Chapman and Dale4 suggest that quartz tubes should be pre-conditioned by repeated determinations of the highest standard. This suggestion was tried and met with little success. Verlinden5 produced evidence of the deterioration of quartz tubes in a closed system when using hydrochloric acid for hydride generation.The end windows of one of our quartz tubes were therefore removed, but the memory effect persisted. Welz and Melcher6 have shown that the presence of oxygen is essential for maximum sensitivity and precision over a wide range of atomisation temperatures. A 1% oxygen - 99% argon purge gas mixture was tried but the problem remained. They found it necessary to cool the central inlet side-arm of their quartz tube to prevent premature decomposition of the hydride before it reached the hot central zone. We therefore returned to the earlier quartz tube arrangement supplied by Instrumentation Laboratory whereby the tube in its holder rested upon the original instrumental burner. The air - acetylene burner was replaced by the shorter slot dinitrogen oxide - acetylene burner but using an air - acetylene flame, as recom- mended.The extreme ends of the tube were now cooler and the memory effect was reduced to High-purity reagents and de-ionised water were used throughout. A solution to the problem was suggested by the work of Thompson and Thomer~on.~COMMUNICATIONS 1159 Most blanks were now of the order of 0.1-1 pg g-l of arsenic in the The improved accuracy and precision of the arsenic determination with this simple modification acceptable proportions. samples. permitted the analysis of the stream sediment samples to proceed. The author thanks Mrs. Dawn Hutchison for her advice and encouragement and the Director, Institute of Geological Sciences (NERC), for permission to publish this paper. References 1. “Atomic Vapour Accessory 440, Operators and Service Manual, ” Instrumentation Laboratory, 2. 3. 4. 5. 6. 7. Wilmington, MA. Verlinden, M., Baart, J., and Deelstra, H., Talanta, 1980, 27, 633. Evans, W. H., Jackson, F. J., and Dellar, D., Analyst, 1979, 104, 16. Chapman, J . F., and Dale, L. S., Anal. Chim. Acta, 1979, 111, 137. Verlinden, M., Anal. Chim. A d a , 1982, 140, 229. Welz, B., and Melcher, M., Analyst, 1983, 108, 213. Thompson, K . C., and Thomerson, D. R., Analyst, 1974, 99, 595. Geochemistry and Petrology Division, Institute of Geological Sciences, Gray’s Inn Road, London, WClX 8NG Received July lst, 1983 Charles H. Branch

ISSN:0003-2654    

DOI:10.1039/AN9830801158

出版商:RSC    

年代:1983

数据来源: RSC

摘要:

COMMUNICATIONS 1159 Simple and Rapid Procedure for the Determination of Lead in Whole Blood by Use of a Slotted Tube and Discrete Nebulisation Flame Atomic-a bsorption Spectrometry Keywords : Lead determination ; slotted tube ; discrete nebulisation flame atomic- absorfition spectrometry Atomic-absorption techniques used to measure the concentration of lead in whole blood, are almost exclusively confined to electrothermal atomisation, Delves cup or chelation - solvent extraction procedures. These techniques all have some drawbacks in that they require the use of expensive accessories, require considerable expertise to achieve reliable results or involve lengthy preparation with relatively large volumes of blood. Simple procedures have been described previously,lP2 whereby lead was released from red cells by protein precipitation agents and the supernatant liquid was assayed by conventional flame atomic-absorption spectrometry. These procedures failed to gain acceptance because of the high scale expansion required to achieve a measurable response and the consequent low signal to noise ratio.Such procedures were, therefore, unreliable a t normal blood lead concentrations. Watling3g4 described a slotted tube that was supported above a conventional burner head. The tube increases the residence time of atoms in the light path of the atomic-absorption spectro- photometer thus increasing the sensitivity of measurement. The elements that show an increase in sensitivity with the slotted tube are volatile elements, such as As, Se, Zn, Cd, Pb and Cu.Three- to five-fold increases in sensitivity have been reported for these elements. We have investigated the use of the slotted tube to measure the lead concentration in whole blood following protein precipitation. Experimental Apparatus Measurements were made using a Pye Unicam SP9-800 atomic-absorption spectrophotometer with a PU9090 video graphics system. The slotted tube (STAT, Pye Unicam, Part No. 9423 390 35011) was 120 nim in length and 8 mm i.d. The tube had two longitudinal slots of 50 and 40 mm, which were a t 180" to each other. The flame is directed into the 50-mm slot and out via the 40-mm slot. Discrete nebulisation measurements were carried out using a Pye Unicam aliquot micro-sampling accessory. The peak-height absorbance was measured during a 6-s read period.Triplicate readings were made and displayed on a PU9090 printer and also on a Pye Unicam PM8251 chart recorder.1160 COMMUNICATIONS Analyst, Vol. 108 Assessment of Performance Absorbance values were determined for aqueous solutions of lead a t concentrations of 50- 1000 ng ml-l by continuous aspiration with and without the slotted tube and by discrete nebulisa- tion of 100-p1 aliquots into the slotted tube. Determination of Lead in Blood A l-ml aliquot of 10% rn/V trichloroacetic acid was placed into a plastic LP4 tube. A 1.0 ml volume of blood was slowly added while the contents of the tube were mixed continuously on a vortex mixer. The tubes were left at room temperature for 15 min and then centrifuged for 10 min a t 2000 rev min-1.The supernatant liquid was removed for the analysis of 100-pl aliquots by discrete nebulisation into the slotted tube. The concentration of lead in samples from the Supra Regional Assay Service lead quality control scheme were calculated by comparison of absorbance readings with those obtained from standards in whole blood, which were prepared for analysis in the same way as the samples. Results Table I shows the improved sensitivity offered by the use of the slotted tube compared with The small loss of sensitivity at higher concentrations using discrete However, this is fully acceptable considering that conventional aspiration. nebulisation of 100-p1 aliquots is also shown. an analysis can be carried out with only 0.3 ml of sample. TABLE I COMPARISON OF ABSORBANCE VALUES FOR CONTINUOUS ASPIRATION AND CONTINUOUS ASPIRATION WITH STAT AND DISCRETE NEBULISATION WITH STAT FOR AQUEOUS LEAD STANDARDS Mean absorbance value Standard concentration/ ng ml-1 50 100 200 400 600 800 1000 Continuous aspiration into flame* 0.002 0.005 0.008 0.016 0.025 0.031 0.040 Continuous aspiration into flame with STAT* 0.006 0.012 0.024 0.047 0.069 0.084 0.115 Discrete nebulisation of 100-p1 aliquots into flame with STAT? 0.008 0.015 0.022 0.043 0.064 0.080 0.103 * Mean of ten 2-s integrations.f Mean of six 100-pl injections. Table I1 presents the results obtained for quality control blood samples, which demonstrate excellent agreement with the mean values obtained by laboratories of the Supra Regional Assay Service who use Delves cup and atomic-absorption methods with electrothermal atomisation.Precisions [relative standard deviations (RSUs)] of 2-5% were obtained for whole blood samples in the 200-600 ng ml-l lead concentration range. The detection limit (20) in blood samples was estimated to be about 20 ng ml-l of lead (n = 10). TABLE I1 ACCURACY STUDY USING QUALITY CONTROL BLOOD SAMPLES SAS* QC. No. Mean SAS* results/pmol 1-1 STAT method/pmoll-l 22 1 2.46 2.52 222 2.04 2.02 223 3.35 3.42 224 1.17 1.06 225 0.96 1.10 * SAS, Supra Regional Assay Service.September, 1983 COMMUNICATIONS 1161 Discussion The use of a slotted tube achieves a sufficient sensitivity for the determination of lead by flame aspiration a t concentrations typical of the normal, non-occupationally exposed population. The procedure described is both rapid and simple and, apart from an atomic-absorption spectrophoto- meter, no additional expensive equipment is required.It should, therefore, be possible for any laboratory with an interest in trace metals to attempt this analysis. The accuracy of the technique, as determined by comparison with results from reference labora- tories, was good and the precision using pulse nebulisation was equal to that achieved with Delves’ cup or electrothermal atomisation. A sample volume of 1.0 ml was used, which gave 1.3 ml of supernatant liquid. As only 0.3 nil is required for a triplicate analysis the method could be performed with as little as 0.3 nil of blood. For this preliminary investigation whole blood standards were employed ; however, more recent results indicate that aqueous lead standards, prepared in 5% m/V trichloroacetic acicl, produce acceptable results. I7urther work is in progress to assess the method over prolonged periods.More recent results indicate that the determination of lead in urine is also possible. M hydrochloric acid and discrete nebulisation of 100- pl aliquots. In this instance discrete nebulisa- tion helps to increase the lifetime of the quartz tube compared with continuous aspiration. Future work includes the investigation of the proposed method for the determination of cadmium in whole blood and urine. The determination of copper (and zinc) in 30-p1 aliquots of sera is also of importance, especially if the sample volume is limited (sample preparation only involves a 20-fold dilution of the sample). However, the iniprove- ment in sensitivity offered by its use will be beneficial to many other problems, for example, the determination of lead and cadmium in natural and potable waters, an area that is the subject of a separate study. Sample preparation only involves acidification with This paper presents the clinical application of the slotted tube (STAT). References 1. 2. 3. 4. Sprague, S., and Slavin, W., At. Absoypt. Newsl., 1966, 5, 9. Cernik, A. A., BY. J . Ind. Med., 1970, 27, 40. Watling, R. J., Anal. Chim. Acta, 1977, 94, 181. Watling, R. J., Anal. Chim. Ada, 1978, 97, 395. Robens Institute of Industrial and Environmental Health and Safety, University of Surrey, Guildford, Surrey, GU2 5XH Received July 7th, 1983 Andrew Taylor Pye Unicam, York Street, Cambridge, CB1 2PX Alistair A. Brown

ISSN:0003-2654    

DOI:10.1039/AN9830801159

出版商:RSC    

年代:1983

数据来源: RSC

摘要:

1162 BOOK REVIEWS Reviews Analyst, Septembey, 1983 LES ENZYMES. PRODUCTION ET UTILISATIONS INDUSTRIELLES. Edited by GILBERT DURAND and PIERRE MONSAN. Biockirnie Appliquee. Pp. xiv + 352. Gauthier-Villars. 1982. Price Fr190. ISBN 2 04 015421 3; ISSN 0248 5192. (In French.) The growing importance of biotechnology and the reasons for it are well known. I t is the thesis of “Les Enzymes-Production et Utilisations Industrielles” that the use of purified enzymes is playing too small a role in this revolution. Advances could and should have been made more quickly as there is a bulk of knowledge and well understood research techniques are available for such developments. I t was felt therefore that bringing this information together under a single cover, in a form that would make it understandable to a larger cross-section of scientists and engineers would stimulate progress in this area.The first part relates the regulation of enzyme synthesis to the gene and describes the elements of strain selection and recombinant DNA techniques. I t continues with a chapter on the growth of micro-organisms for enzyme production and this is followed by chapters on the purification and immobilisation of enzymes. The second part deals with industrial applications of enzymes. There is a general chapter followed by three short ones describing the uses of glucose isomerase, lactases and penicillin amidase (acylase) . This section concludes with an important chapter on the hazards, both real and possible, of using enzymes. The third part describes a variety of analytical procedures involving enzymes including general assay methods and immunoassays.The final part covers the kinetics of enzymes, free and immobilised, and the association of enzymes with artificial membranes. The individually authored chapters are written clearly and should be understood readily with a minimum of biochemical background. The emphasis is placed on a wide coverage of the subject matter without too much depth, together with examples in industrial use. For this reason more emphasis could have been placed on suitable further reading. Also, although it is understandable that references in a book such as this should be kept to a minimum, when authors names and year of publication are printed I believe the full reference should be available.This fault lowers the value of some of the tables. I was surprised not to find any mention of the use of proteolytic enzyme inhibitors in the early stages of purification schedules. The readership of this book would, I imagine, like a more comprehensive index. For example, cyanogen bromide is indexed only at p. 100 but extra useful information is present on p. 72. It is difficult to see anyone, unless already close to the field, not finding some area of interest in the book. I t would make good general reading for undergraduates to enable them to fill out their coursework, particularly in preparation for a biotechnology course (and incidently help them to brush up their French). The book would also be of value to chemists and chemical engineers who were interested in seeing the potential of enzymes not only in an industrial but also in an analytical setting. The book is divided into four parts.These complaints are, however, rather minor. J . A. HILL PRINCIPLES OF QUANTITATIVE X-RAY FLUORESCENCE ANALYSIS. By R. TERTIAN and F. CLAISSE. The authors of this book have presented the X-ray fluorescence community with a worthwhile addition to its rather sparse base of over-view literature. “Principles of Quantitative X-Ray Fluorescence Analysis” treats a carefully defined range of topics, exactly as promised by the authors in their preface. I t surveys X-ray theory and the application of that theory to analytical chemistry. It does not describe analytical X-ray instrumentation or equipment operation, as do books by such authors as Birks, Liebhafsky and Woldseth.Further, it does not delve into specific applications in the same way as does Muller’s “Spectrochemical Analysis by X-ray Fluorescence.” Instead, methodology is presented for carrying out a wide range of analytical procedures on heterogeneous as well as homogeneous specimen types. The first 30% of the book is a clear and concise review of X-ray physics with specific develop- ment of those aspects essential to the field of chemical analysis. Numerous citations are given here and throughout the book, providing a very valuable aid to those wishing to research further the concepts presented. Chapters 5 and 7 on inter-element effects provide a firm foundation for the book’s main subject: correction of absorption - enhancement effects.Pp. xvii + 385. Heyden. 1982. Price L30.00. ISBN 0 85501 709 0.BOOK REVIEWS 1163 A t the heart of the book, we find the full range of correction and compensation techniques. Described are the fundamental parameter method, empirical correction methods, external standards, internal standards, addition method, dilution, double dilution, scattered radiation, thin-film methods, fusion and others. The techniques are presented clearly, but not a t a beginners level. The authors have intended their work for advanced students and practising X-ray spectro- scopists. Reviewers frequently find some small point to criticise, in even the best of books. This is no exception; but, as I cannot be fully objective, each reader should form his own opinion. Critiques a t the end of each section on a computational method would be helpful to the reader.However, the authors have not provided them uniformly. In concluding their remarks on the Rasberry - Heinrich algorithm, the authors criticise the method as having three imperfections (see p. 164). While their first point is correct, it is also appropriate to the other empirical methods reviewed. The second two points are not entirely correct. One evidence of this is the use of the Rasberry - Heinrich method to determine accurately molybdenum (and cobalt) in iron - nickel - chromium alloys (see Grant, C. L., Editor, “Advances in X-Ray Analysis, 17,” Plenum Press, 1974, pp. 309- 317). I believe X-ray fluorescence analysts will find it quite useful. I believe they have met their goal.Lest I sound like a complainer, let me once more recommend this book. S. D. RASBERRY MASS SPECTROMETRY ADVANCES 1982, PARTS A AND B, AND PARTS C AND D (IN 2 VOLUMES). PROCEEDINGS OF THE QTH INTERNATIONAL MASS SPECTROMETRY CONFERENCE, VIENNA, 30th AUGUST-^^^ SEPTEMBER 1982. Edited by E. R. SCHMID, K. VARMUZA and I. FOGY. Pp. xlii + 379 (Part A); xviii + 544 (Part B); xviii + 544 (Part C); xvi + 461 (Part D). Elsevier. 1983. Price $361.75; Dfl850. ISBN 0 444 42158 0 (Parts A & B); 0 444 42159 9 (Part C & D); 0 444 42160 2 (set). Reprinted from the International Journal of Mass Spectrometry and Ion Physics, Volumes 45-48. Despite the ever increasing cost of the equipment, mass spectrometry has, within the last 15 years, become a standard analytical technique in academic, hospital and industrial laboratories, and i t has found applications in fields as diverse as those of space research and the study of old master paintings.Its widespread use is amply demonstrated in the present work, which contains the full texts of 7 plenary and of 19 keynote lectures and four-page summaries of each of the 374 papers contributed to the 9th International Mass Spectrometry Conference, held in Vienna. The plenary and keynote lectures, presented by eminent mass spectroscopists, who either initiated or made important contributions to the facets that they discuss, provide a series of well documented, critical reviews, The topics include isotopic analyses of inorganic and organic substances, new ionisation methods, structure elucidation of organic compounds, chromatography combined with mass spectrometry, quantitative measurements in biochemistry and medicine, isotopic analyses in nuclear and geological studies and the examination of air pollutants. The present state of each topic is surveyed and future developments are considered. The contributed papers, which cover all aspects of mass spectrometry, have been split into 17 subject groups, of which those on instrumentation, combined gas chromatography - mass spectro- metry, liquid chromatography - mass spectrometry and mass spectrometry - mass spectrometry, fast-atom bombardment and secondary ion mass spectrometry, structure elucidation, biochemical and medical applications and environmental and food chemistry applications are likely to interest practising analysts.A casual browse through the volumes reveals the way in which mass spectrometry has advanced since the 8th Conference, held in Oslo in 1979. Ionisation methods, such as secondary ion mass spectrometry, which was beginning to attract attention in 1979, and fast-atom bombardment, first reported in 1981, are now in common use, and are featured in many papers. The reports, describing the relative merits of field desorption, laser desorption, californium-252 plasma desorption and fast-atom bombardment methods for ionising molecules of different types, are of special interest. By using these soft ionisation methods, compounds that are difficult to volatilise, such as sugars, dyestuffs, steroids and antibiotics, which previously needed careful derivatisation, can now be examined directly.Many contributions describe applications of mass spectrometry in combina- tion with other separation procedures. A comparison of the relative utility of mass spectrometry -1164 BOOK REVIEWS AGalyst, Vol. 108 mass spectrometry and of liquid chromatography - mass spectrometry, for studying alkaloids in ergot fermentation extracts, is noteworthy. The volumes have been produced by photographic reproduction of the authors’ unedited type- scripts, and there are, consequently, occasional typing errors and linguistic infelicities ; these blemishes could have been avoided by careful editing. Nevertheless, rapid publication is to be welcomed. Much of the information disseminated at a conference loses its value if publication is delayed. This comprehensive work provides an impressive survey of the range and the state of mass spectrometry in mid-1982.Many analysts, who are not dedicated mass spectroscopists, could profit from a perusal of the contents pages to see how mass spectrometry is progressing, and to find out how i t could help in their particular field. Copies of the two volumes or of the corre- sponding volumes of the International Journal of Mass Spectrometry and Ion Physics should be available in mass spectrometry libraries. Other libraries will be deterred by the high cost. J. E. PAGE PETROANALYSIS ’81. ADVANCES IN ANALYTICAL CHEMISTRY IN THE PETROLEUM INDUSTRY, Wiley Heyden (on behalf of the 1975-1982. Institute of Petroleum). 1982. Price k36. ISBN 0 471 26217 X. Edited by G.B. CRUMP. Pp. xiv + 456. As its title implies, this book is based on papers presented at a Symposium organised by the Institute of Petroleum in London in October 1981. The 37 chapters cover a very wide range of topics and, whilst one or two of them seem to have only a nodding acquaintance with analysis, the average analyst in the petroleum industry will certainly find something of interest in a majority of them. All of the “big” techniques, such as the various chromatographies and spectroscopies are represented, and the ubiquitous microprocessors get a chapter to themselves. There are even a couple of papers for the “wets,” not those of a certain political persuasion but those who dabble in the black non-instrumental arts of analysis. Apart from the techniques themselves, their application in various aspects of the industry are also covered from exploration to pollutants, from extraction to oil spills, from sea water analysis to analysis of the metals used for plant con- struction.The Editor and some of the authors draw attention to the considerable changes that have taken place in the analytical scene since the previous IP analytical symposium in 1974. These changes are all the more impressive as they relate to methods and techniques that are commonly used and not to the more esoteric “state of the art” instrumentation. All in all a most useful and interesting compendium that will be read with profit by many practising analysts in the petroleum‘industry, but only one suspects if their Company or Institution buys it for the library; A36 whilst much cheaper than attending the conference, is still a hefty price to pay 18 months after the event.Even oil shale and coal liquefaction get honourable, and interesting, mentions. G. E. PENKETH PRAXIS DER KAPILLAR-GASCHROMATOGRAPHIE, MIT BEISPIELEN AUS LEBENSMITTEL- UND UMWELTCHEMIE. By ERHARII SCHULTE. Anleitungen f u r die chemische Laboratoriums- praxis, Band XVIII. Pp. x + 162. Springer-Verlag. 1983. Price DR184; $33.60. ISBN 3 540 12029 7 ; 0 387 12029 7. (In German.) Although the capillary column for use in gas chromatography was invented over 25 years ago it seems that only in the last few years have books on the topic abounded, probably because great improvements have been made over that period of time in the application of columns of this type.This book is divided into four main chapters or parts, a brief introductory one classifying the different column types and materials, a second dealing with the production of the columns and the use of various stationary phases, a third on the installation and operation and a fourth about applications. The applications mentioned include : pesticides, carbohydrates, plasticisers, polycyclic aromatic hydrocarbons, chlorinated hydrocarbons and amino acids, but these are not as numerous as one would wish in a book of this type. There are about 600 references, grouped together at the end of the book (a high proportion in English), together with addresses of suppliers and an adequate index.September, 1983 BOOK REVIEWS 1165 The volume no doubt will be purchased by libraries but the reviewer feels that it is quite expensive bearing in mind that there are only about 160 pages and while it is well written and arranged the text does not offer significantly more than do existing books in the field.It may be recommended to German-speaking chromatographers who may not have ventured very far from the field of packed to capillary columns. D. SIMPSON APPLIED COMPLEXOMETRY. By RUDOLF P~IBIL. Pergamon Series in Analytical Chemistry, Volume 5 . Pp. xvi + 410. Pergamon. 1982. Price $75. ISBN 0 08 026277 5. In the 1950s and early 1960s complexometry with EDTA was a mainstream research and development topic in analytical chemistry. In those days Professor Pribil was recognised world- wide as one of the chief innovators.Few of the younger generation of analytical chemists may remember how difficult i t was before the advent of Schwarzenbach’s technique of complexometry to find titrimetric methods for the determination of metal ions in solution except where one could use changes in valency state, e.g., Cr(V1) + Cr(II1) to form the basis of a redox titration. As a result most metals could only be determined accurately by much slower gravimetric procedures. Complexometry was to the accurate determination of macro-amounts of metals in solution what the 1960s technique of atomic-absorption spectrometry became for trace elements in solution, a near-universal, almost fool-proof technique. Rudolf Pi-ibil (Senior) made a phenomenal contribution to the development of complexometric indicators, to masking agents and to titrants other than EDTA within the same aliphatic and alicyclic aminopoly carboxylic acid family. The technique is now a well established and uni- versally accepted one with apparently few frontiers left to cross and few if any major problems left to solve.This book, dedicated to his wife Vlasta and translated by his eldest son Rudolf, also a very considerable chemist, is in many respects a memorial to the author’s skill as a chemist and to his enormous knowledge of chemical reactions and how to manipulate them. However, it is not a memorial in the sense that it is dated or a thing of the past. It is lively in its approach, up-to- date and likely to remain a current book for a greater number of years than most of those now appearing on the analytical bookshelf.It is written with a refreshing originality t h a t pops up from time to time in phrases such as “I hold it more convenient . . .,” p. 59, and various turns of phrase that used to charm attentive audiences a t numerous demonstrated lectures he gave from time to time in the UK. The demonstrations always worked, as did the analytical procedures he himself evolved. It is a pleasure for one who sat a t his feet waiting for new mysteries to evolve to pay tribute to this extremely attractive and worthwhile book. It takes initially a wide view of complexometric titrants, indicators, masking agents, classifi- cation of complexes and then passes on to a detailed treatment of the titrimetric behaviour of cations and, indirectly, anions, and then, becoming intensely practical, i t deals with the analysis of alloys, rocks, minerals, ores, slags, cements and so on.This book is a veritable bible of complexometry, erudite, innovative and, a t the same time, eminently practical and useful. No longer a new technique, complexometry is, however, widely and extensively used. No respectable “complexometrist” should be without this book. T. S . WEST EUROANALYSIS IV. REVIEWS ON ANALYTICAL CHEMISTRY. Edited by L. NIINISTO FOR THE WORKING PARTY ON ANALYTICAL CHEMISTRY OF THE FEDERATION OF EUROPEAN CHEMICAL SOCIETIES. Pp. 258, AkadCmiai Kiad6/Association of Finnish Chemical Societies. 1982. Price FIM160 (420 approx.). ISBN 963 05 3127 5 (AkadCmiai Kiad6); 951 9223 14 2 (Ass. of Finnish Chem. SOC.). This volume will be welcomed by those who attended and the many who, on grounds of cost, did not attend Euroanalysis IV, Helsinki, 1981.It is useful to have a complete record of the invited lectures, all of which contained excellent material but a number, owing to linguistic or stylistic problems, are much better in written format than they were as oral presentations. Like earlier conferences Euroanalysis IV was a broad-spectrum meeting covering some of the important topics of current analytical interest; certain areas were treated in more depth in the three Special Sessions. Although not a Special Session, historical aspects were given some emphasis via H. A. Laitinen’s1166 BOOK REVIEWS Analyst, Vol. 108 interesting account of “The Development of Analytical Chemistry as a Scientific Discipline.’, A link was provided with the previous conference Euroanalysis 111, Dublin, by 0.Makitie who outlines the life and work of “Johan Gadolin and his Contribution to Analytical Chemistry.,’ Gadolin it was noted, visited Dublin and studied minerals with Richard Kirwan. The first special session “Analytical Chemistry, the Analyst and Society” was also the title of its first lecture given by H. Egan; this was in many ways a link with a Symposium the previous week in Helsinki on the Harmonisation of Collaborative Analytical Studies. This was followed by a thought provoking account by W. Pfannhauser of “The Responsibility of the Analytical Chemist amid the Conflicting Interests of Government, Industry and Consumer, ” illustrated by the selected examples of mercury and selenium content of food, PAHs and food flavourings.Special Session I1 concerned “Mass Spectrometry in Inorganic Analysis.’, G. I. Kamendik discussed “New Developments and Current Trends in Spark Source Mass Spectrometry. ” This paper usefully draws attention to the urgent need to develop the theoretical basis of the subject in order that it may advance. Applications and new ion sources were stressed by I . Cornides in his paper “Inorganic Mass Spectrometry for Trace Analysis.” A. Lodding in “Trends and Developments in Secondary Ion Mass Spectrometry for Microanalysis” deals at length and in detail with factors affecting detection limits, quantitation, spacial resolution as well as keynote trends in SIMS performance. The third Special Session, “Symbolism in Analytical Chemistry” is represented in the paper by V.Simenov and H. Malissa “The Visual Image as Information Source in Analytical Chemistry,,’ I, for one, remain to be convinced of the need to take into chemistry the recent semiotic trends in literature or cinema. Experience of chemical analysis performed on board the Swedish ice-breaker YMER formed the basis of D. Dyrssen’s paper “ AAA-Artic Automatic Analysis,” apart from the more conventional analyses, amino acids and halocarbons were determined. The theme of environmental analysis was continued by K. Ballschmiter in his discussion and critical evaluation of problems that arise when using “High Resolution Gas Chromatography in Environmental Analysis. ” The problems of purity of reagents and contamination from the laboratory and its personnel were surveyed by E.Wanninen under the title “Trace Analysis and the Contamination Problem.” J. Slanina posed an intriguing question, “Ion Chromatography, a Panacea for Environmental Analysis ? I J and showed that the technique was coming of age and was now a powerful, indispensable tool within its limitations, which were now known. The last paper in this volume by P. G. Byrne, “Environmental Asbestos Analysis” appears displaced as it clearly belongs to the group of papers just outlined. This practical paper deals with the relative roles of phase contrast light microscopy, SEM and TEM and the choice between them and concludes with a discussion of the future role of the Health and Safety Directorate of the EEC in the formulation of reliable asbestos monitoring techniques.This series of papers on environmental topics are in effect a fourth Special Session and form a useful overview of recent aspects of the subject. The advantages, disadvantages and future prospects of “Polarography and Voltammetry in the Analytical Laboratory and in Process Control” were outlined by 2. Kowalski. The improvements attainable by computer support of infrared spectroscopy were detailed by D. Hadii in “Mini- computer Coupled Infrared Spectroscopy-its Appreciation as an Analytical Tool. ,’ These improvements include data acquisition and processing, quantitative multicomponent analysis, coupling to chromatography and finally in structure elucidation. P. V. Huong gave a wealth of experimental detail and applications over a wide field following a suecinct introduction to the theory, in a survey of “New Analytical Possibilities of Raman and Resonance Raman Spectroscopy.” The most interesting and stimulating contents reflect the care and attention given by the Praesiduim (D. M. Carroll, A. Hulanicki, H. Malissa and L. Niinisto) to the selection of topics and lecturers. The volume represents very good value being half the price of the previous Euro- analysis volume; however, fewer papers are included, the printing and presentation are of a lower, yet acceptable quality, although a fair number of proof reading errors were noted, e.g., p. 24, 1812 not 1822; p. 30, 41 Thorburn not Thornburn; p. 64, 70 automation not automatization, usefulness not usefullness; p.128 sulphur not sulfur; p. 134 o-phthaldialdehyde not orthophtalidaldehyde; p. 155 hormones not hormons; p. 165 bismuth not bismut, wear not bear; p. 167 antiseptic not anticeptic; p. 180 NO, not No,; p. 188 AutoAnalyzer not auto-analyser. D. THORBURN BURNSSeptember, 1983 BOOK REVIEWS 1167 OPTICAL RADIATION MEASUREMENTS. VOLUME 3. MEASUREMENT OF PHOTOLUMINESCENCE. Edited by KLAUS D. MIELENZ. Pp. xvi + 319. Academic Press. 1982. Price $47. ISBN 0 12 304903 2. This volume in the present series concerned with Optical Radiation Measurements is devoted to the measurement of photoluminescence. It consists of seven chapters from distinguished authorities in various aspects of photoluminescence and its measurement. It begins with a general description of photoluminescence spectrometry (K.D. Mielenz) and is then followed by a most interesting chapter concerned with new developments relating to spectrofluorimetry and photon yield measurements (E. F. Zalewski). The correction of excitation spectra and an evaluation of sample-induced errors in fluorescence spectrometry are dealt with in authoritative fashion (W. H. Melhuish) . Fundamental aspects of luminescence emission and spectroradiometric calibration methods applied to the correction of emission spectra are then considered (Costa, Mielenz and Grum). An interesting and informative review of methods available for the measurement of proton yields is then presented in the space of 50 pages (Demas) and this is followed by an excellent chapter concerned with data handling in fluorescence spectrometry.Measurements of photoluminescence play an increasingly important role for a variety of industrial processes involving the application of fluorescent dyes and phosphors. These include the use of fluorescent whitening agents to give an apparent enhancement of the reflectance of paper, plastic and textile products; applications of fluorescent inks and dyes in the graphic arts and photographic industries; the use of fluorescent dyes for warning signs and other safety devices; the application of fluorescent dye penetrant solutions for the non-destructive crack testing of machine parts. In all these applications, the main objective of the measurement is to determine the colour and appearance of fluorescent objects when irradiated under specific conditions of daylight or artificial illumination. Approximate measurements of this kind can be made with conventional, one-monochromator reflection spectrophotometers that have been suitably modified ; hence fluorescence colorimetry is commonly regarded as an extension of reflectometry rather than as a companion of analytical fluorimetry.On the other hand the experimental techniques used for accurate measurements are essentially the same in both disciplines, because it is well docu- mented that the complete radiometric characterisation of fluorescent samples always requires the use of two monochromators for monochromatic sample irradiation as well as monochromatic detection for fluorescence emission. In this volume, the similarities of analytical fluorimetry and fluorescence colorimetry are emphasised.This has been accomplished, as described above, by inviting experts from both disciplines as contributing authors and by attempting a unified treatment based on theoretical models that apply in both fields. The main emphasis throughout the volume is on experimental methods. The contributions made by all the authors are intended to interrelate theory and instrument design with the methodology required for real samples. The book is well produced and moderately priced a t 1983 costs and must be recommended to all those with an interest in photoluminescence measurement techniques and applications. It presents a worthwhile, definitive and authoritative description of the field of photoluminescence measurement. G. F.KIRKBRIGHT ANNUAL REPORTS ON NMR SPECTROSCOPY. VOLUME 13. Academic Press. 1982. Price k53.80; $99.50. ISBN 0 12 505313 4; ISSN 0066 4103. Edited by G. A. WEBB. Pp. x + 399. This book is divided into four chapters: two for organic chemists, one for an inorganic or organometallic chemist and one for a physical chemist. This means i t should be alongside the earlier volumes on library shelves but it is unlikely to be on the private bookshelves of individuals. The first two chapters with coverage of mono- and oligosaccharides by K. Block and H. Thagerson and of alkaloids by T. A. Crabb are each authoritative and exhaustive accounts of these areas. While the widespread availability of high field NMR is known, these chapters do remind the non- organic chemist of the extent to which NMR parameters, especially those relating to I3C, are available on what seems to be every compound known to Chemical Abstracts.There are 16 tables and 330 references relating to the sugars while the alkaloid information is largely presented attached to the 601 structural formulae; such formulae are welcome as the names, from adlumine to yamataimine are uninformative except to the devoted specialist, The alkaloid chapter has1168 BOOK REVIEWS Analyst, Vol. 108 336 references, virtually all to literature published in 1977 or later. Both these chapters are valuable for those with a need to know. Thallium has a dominant isotope, ,05Tl, with I = 1/2 and a fairly large magnetogyric ratio, implying a resonant frequency of 57.7 MHz in a field where the lH resonance is a t 100 mHz.Consequently, it is a very favourable element for NMR and the chapter on its NMR spectroscopy by J. F. Hinton, K. R. Metz and R. W. Briggs has sections on both Tl(1) and Tl(II1) species in aqueous and other solutions and on their organometallic derivatives. Also briefly covered are solids, alloys, glasses and zeolites containing T1. The attraction for work on T1 includes relaxation features free from quadrupole coupling effects, and very large chemical shifts, as would be expected for an atomic number as high as 81, so that shifts can be accurately measured as a function of concentration, solvent, etc. The sensitivity to changes is indicated by Tl+NO,-, which has a shift of - 11 p.p.m. at a concentration of 0.5 mol dm-, with reference to infinite dilution. In dimethyl sulphoxide the shift is +369 p.p.m.and in butylamine it is +1708 p.p.m. compared with water. The spin - spin couplings are also large; for a typical ,05Tl - 13C - lH molecular fragment lJT,,c w 2500 Hz and 2JT,,H w -400 Hz. With 21 tables and 307 references this chapter is a mine of information for the thallium chemist. The final chapter “Rotational Correlation Times in NMR” by R. T. Boer4 and R. G. Kidd is a thorough treatment of what NMR can tell us, through measurements of the nuclear relaxation times, T, and T,, about molecular motions, especially rotational motions, in liquids. This chapter makes clear the general relation between nuclear relaxation times and the time dependence of the features causing relaxation, namely quadrupole couplings, nuclear dipole - dipole couplings, chemical shift anisotropy and spin - rotation couplings.In the first three instances the informa- tion refers to the correlation functions of the second-order tensors bound to the molecular frame while spin - rotation refers to an angular velocity correlation function. The present treatment, based on NMR, simplifies the problem and talks in generalities about tensors without always specifying the axis system or the relation of diffusional tensors to NMR tensors, which may, or more often may not, have principal axes in the same directions in the molecule. There are many other techniques that can be applied to the same problem, including line widths in Rayleigh and Raman scattering, dielectric properties, some infrared line widths, time dependent Kerr and Pockels effects and so forth.The total complexity of the over-all problem of motion in liquids is rather hidden here by the simplifications and restriction to NMR; but for those interested specifically in the interpretation of NMR experiments the chapter is most illuminating. D. H. WHIFFEN ANNUAL REPORTS ON ANALYTICAL ATOMIC SPECTROSCOPY, VOLUME 11. REVIEWING 1981. Edited Royal Society of Chemistry, 1982. by M. S. CRESSER and B. L. SHARP. Price 448; $88. Pp. xiv + 375. ISBN 0 85186 707 3 ; ISSN 0306 1353. With Volume 11 of the ARAAS I once again have had the opportunity to read through the endeavours of the band of scientists who continue to explore the analytical applications of atomic spectroscopy. Many of these are already known through normal literature channels but others, presented as conference papers, are new material, and as I have written in previous reviews of this series, this collation of conference papers is one of the major strengths of the publication. Its continued presence is a tribute to the efforts of those who have taken on the task of providing that information. However, its contents reflect the changes that have been taking place. As one might expect there is more emphasis on plasmas and it is worth noting that in the Editors’ view the papers on plasmas reviewed demonstrate a more mature assessment of the state of the art than those reported in earlier volumes. It is also pleasing to note the inclusion of material on the speciation of trace elements. The use of atomic spectroscopy in this area is not new. This is an increasingly important area of analytical science well worthy of inclusion in its own right. The applications section of the review continues to expand, providing up-to-date methodology for the multiplicity of analyses performed by atomic spectroscopy. The application tables must be a great boon for those engaged in the analysis of specific materials; they have certainly proved their worth in this laboratory on more than one occasion. JOHN AGGETT In most respects Volume 11 continues in the style of the preceding volumes. I recommend this Volume to all analytical spectroscopists.

ISSN:0003-2654    

DOI:10.1039/AN9830801162

出版商:RSC    

年代:1983

数据来源: RSC