摘要:

Analyst, January, 1979 79 SHORT PAPERS Determination of S-Methylmethionine in Plant Products by Use of an Automatic Amino-acid An a I yse r E. G. Kovatcheva Department of Analytical Chemistry, Higher Institute of Food Technology, Lcnin 26, 4000 Plovdiv, Bulgaria Keywords S-Methylmethionine determination ; amino-acid analyser ; plant $woducts Several methods have been reported for the determination of the anti-ulcer factor S-methyl- methionine in plant products.1-5 The method of Skodak et aZ.,l which involves the use of an automatic amino-acid analyser, has the highest accuracy and reproducibility but requires a long separation time (9 h) and a minimum change (4.26 to 4.32) in the pH of the buffer solution used as eluting agent in order to ensure a good separation of S-methylmethionhe from the basic amino acids.The proposed method overcomes these difficulties, requiring a separation time of only 1 h. Experimental Apparatus Automatic amino-acid analyser, Hd 1200E, Zavod, Ziar Nad Hronom, Czechoslovakia. Reagents and Materials All reagents should be of analytical-reagent grade. Plant products. Cabbage, kohlrabi, celery and sweet corn were obtained from the Plovdiv Higher Agricultural Institute. Amino acids. Lysine, arginine, ornithine, histidine and DL-S-methylmethioninium chloride (Merck). Standard solution of 3-amino-3-carboxy~ropyZdimethyZ chloride (m.-S-methyZmethioninium chloride), 1 pmol ml-l. Dissolve 0.1997 g of DL-S-methylmethioninium chloride in 1 1 of 0.01 N hydrochloric acid. Standard solution of basic amino acids. Prepare a solution containing 1 pmol ml-l each of the five basic amino acids listed above in 0.01 N hydrochloric acid.HydrochZoric acid solution in 70% ethanol, 0.1 N. Mix 2 ml of 5 N hydrochloric acid with 98 ml of 70% ethanol. Sodium citrate bufer solution, 0.3 N. Dissolve 21 g of citric acid and 300 ml of 1 N sodium hydroxide solution in 1 1 of water. Adjust the pH of the solution to 7.00 6 0.10. Citrate-phosphate bufer solution, pH 8.0. Mix 2.8 ml of 0.1 N citric acid solution with 97.2 ml of 0.2 M disodium hydrogen orthophosphate solution. Dowex 50-X8 (100-200 mesh). SP-Sephadex C-25. From Fluka, Switzerland. From Pharmacia Fine Chemicals, Sweden. Procedure Homogenise plant samples containing 0.54.0 mg of S-methylmethionine and extract three times with the 0.1 N solution of hydrochloric acid in 70% ethanol using a ratio of plant to acid solution of 3 + 1 m/V.3 Combine the extracts and distil off the ethanol under vacuum at 50 "C.Adjust the aqueous solution that remains to pH 8.0 and pass the solution down a column (9 mm id.) containing 10 ml of Dowex 50-X8 cation-exchange resin in the ammonium form. Wash the column with 40-50ml of distilled water, elute the basic amino acids with 20ml of 2 N ammonia solution and evaporate to dryness at 50 "C. Alternatively, adjust the aqueous residue to pH 6.0 and apply it to a column containing 15 ml of SP-Sephadex C-2580 SHORT PAPERS Analyst, Voi. I04 in the sodium form. Wash the column with distilled water as before and elute the basic amino acids with 20 ml of 0.2 M citrate - phosphate buffer solution, pH 8.0.Evaporate the effluent to dryness at 50 "C. Dissolve thle residue in 1 or 2 ml of 0.1 N hydrochloric acid and apply a 0.1-ml aliquot of the solution to thlecolumn of the amino-acid analyser (100 x 5.3 mm i.d.) at 50 "C. Separate the amino1 acids by passing 0.3 N sodium citrate buffer solution through the column at a flow-rate of 22 ml h-l for 60 min. Use the standard solution of DL-S-methylmethioninium chloride as an external standard to determine the amount of S-methylmethionine in the sample, which is calculated from the area of the peak. The thin-layer chromatographic method used for the determination of S-methylmethionine is described in reference 3. $ Results and Discussion ( 6 ) Neutral amino ;Lys The chromatogram showing the separation of S-methylmethionine from the standard solution of the basic amino acids is shown in Fig.l ( a ) . The procedure described for the determination of S-methylmethionine in plant products was applied in a study of its content in certain plant products. The results obtained are given in Table I. The chromatogram of the amino acids in a cabbage sample is shown in Fig. l ( b ) . It is evident from Table I that both Dowex 50-X8 in the ammonium form and SP-Sephadex C-25 in the sodium form can be used successfully in a preliminary purification of the plant extracts. In subsequent expe:riments preference was given to Dowex 50-X8 because it is simpler to use and is more readily available. I Lvs 0.6 0.5 0.4 0.3 0.2 0.1 0 15 30 45 60 75 90 105 Time/min Fig.1. Chromatograms produced on a 100-mm column of an amino-acid analyser with 0.3 N sodium citrate solutilon (pH 7.00) as eluting agent: (a), standard solution containing 1 pmol ml-l of each amino acid; (b), 30 g of cabbage extract purified with Dowex 60-X8 in the am- monium form (0.97 mg of S-methylmethionine) ; and (c), the same sample as for (b) but after treatment at pH 10.0 for 30 min at 120 "C. MMS = S-Methylmethionine, his = histidine, lys = lysine, orn = ornithine and arg = argi- nine.January, 1979 SHORT PAPERS TABLE I DETERMINATION OF S-METHYLMETHIONINE IN PLANT PRODUCTS 81 Sample Cabbage 1 . . Cabbage 2 . . Kohlrabi 1 . . Kohlrabi 2 . . Celery 1 . . Celery 2 . . Celery 3 . . Sweet corn 1 . . Sweet corn 2 . . Dry matter, % .. 6.05 . . 6.20 .. 9.86 .. 10.60 . . 11.60 . . 11.95 . . 12.20 . . 22.34 . . 21.70 Amount of S-methylmethionine (mg per 100 g) after purification with- Dowex 50-X8 3.23 4.36 8.05 7.25 6.24 6.30 5.04 4.58 5.60 SP-Sephadex C-25 3.10 4.21 8.44 7.20 6.00 6.08 5.04 4.76 5.86 The successful application of the proposed method to the determination of S-methyl- methionine in plant products is confirmed by the fact that a peak due to S-methylmethionine is not present on the chromatograms of heat-treated samples (30 min at 120 "C, pH 10.0) of cabbage, celery and kohlrabi and no other ninhydrin-positive substance is detected in its place [Fig. 1 (c)] . Under the conditions described,*s6 S-methylmethionine decomposes completely to dimethyl sulphide and homoserine, causing an insignificant increase in the height of the peak due to neutral amino acids.TABLE I1 DETERMINATION OF S-METHYLMETHIONINE IN PLANT JUICE The S-niethylmethionine in the celery juice had been decomposed by heating before addition of further S-methylmethionine. Amount of S-methylmethionine in 30 ml of celery juice/mg Sample r- No. Added 1 0.50 0.48 2 1 .oo 0.98 3 2.00 1.94 4 3.00 3.00 5 4.00 3.90 Coefficient of Relative error, 4.1 4.0 3.5 2.0 2.8 3.0 2.6 0 2.6 2.5 Average k 2 . 3 variation, % % * Ten determinations. The accuracy of the method was tested by use of a standard-additions method. Celery juice in which the S-methylmethionine had been decomposed by heating (30 min at 120 "C, pH 10.0) was used. Amounts of 0.54.0mg of S-methylmethionine as the chloride were added to 30-ml samples of celery juice.The samples were purified with Dowex 50-X8 in the ammonium form and the amounts of the amino acid determined. The results obtained are given in Table 11. The statistical evaluation shows a high degree of reproducibility with a coefficient of variation ranging from 2.6 to 4.1%. An average accuracy of &2.3y0 was obtained. The proposed method was compared with the thin-layer chromatographic method for the determination of S-methylmethionine developed earlier.3 The reproducibility of the two TABLE I11 COMPARISON OF THE S-METHYLMBTHIONINE CONTENT OF 30ml OF CELERY JUICE DETERMINED BY TWO METHODS Mean content of Standard Coefficient of Method ten samples/mg deviation/mg variation, yo Amino-acid analyser . . .. 2.06 0.055 2.7 Thin-layer chromatography . . 2.17 0.119 5.582 SHOIlT PAPERS Analyst, Vol. 104 methods was determined by applying each one to a set of ten samples of celery juice. The test samples were purified by passing them through Dowex 50-X8 in the ammonium form. The results obtained are given in Table 111. The coefficients of variation for the proposed method and for the thin-layer chromatographic method are 2.7 and 5.5%, respectively. Thus the proposed method, which is more accurate and more reproducible than the earlier method, is recommended for the determinat:ion of the S-methylmethionine content of plant products. References 1. 2. 3. 4. 5. 6. Skodak, F., Wong, F. F., and White, L. M., Analyt. Biochenz., 1965, 13, 568. Telegdy Kovats, L., Berndorferne Kraszner, E,, and Pokolnd Shi, K., l&dnzZ. Ipar., 1974, 28, 289. Kovatcheva, E. G., and Popova, Y. G., Nahwng, 1977, 21,465. Hutschua, G. N., and Stassjak, A. B., Prikl. Biokhim. Mikrobiol., 1975, 11, 914. Bezzubow, A. A., and Gessler, N. N., Prikl. Biokhim. Mikrobiol., 1977, 13, 301. Keenan, T. W., and Lindsay, R. C., J. Dairy Sci., 1968, 51, 112. Received February 23rd, 1978 Accepted June 15th, 1978

ISSN:0003-2654    

DOI:10.1039/AN9790400079

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

82 SHORT PAPERS Analyst, Vol. 104 Determination of Bifunctional Compounds Part IV.* 4-lodobutaneboronic Acid as a Selective Reagent for the Trace Determination of Bifunctional Compounds C. F. Poole, S. Singhawangcha and A. Zlatkis Department of Chemistry, University of Houston, Hoirstogz, Texas 77004, USA Keywords : Gas chromatography with electron-capture detection ; bifunctional compounds ; cyclic boronic esters ; 4-iodobutaneboronic acid Polyfunctional molecules in biological systems represent a complex separation problem in analytical chemistry. One method of simplification is the use of selective reagents to aid in the isolation or determination of that part of the sample of interest. Many biologically important substances (e.g., steroids, prostaglandins, catecholamines, carbohydrates) are bifunctional, Le., contain protonic or ketone functional groups on 1,2-, 1,3- or 1,4-carbon atom systems.A useful reagent for the selective reaction of these compounds is the boronic acid group, which forms stable cyclic boronic ester derivatives1 A limitation of the alkyl and aromatic boronic acids in current use is that the derivatives are determined after gas chromatography with the flame-ionisation detector (FID) and thus no discrimination in favour of the boronic esters is obtained over the organic background. Also, the sensitivity is limited to the performance of the FID. The introduction of an electron-capturing rnoiety into the organic part of the boronic acid reagent provides the dual advantage of suitability for trace determination (high sensitivity) and discrimination against the organic background when used in gas chromatography with the electron-capture detector (ECD) .In previous studies we have evaluated substituted aromatic boronic acids for this purpose.2J As an alternative approach we reported on the properties of polynuclear aromatic boronic acids for use in high-performance liquid and thin-layer chromatography with selective fluorescence detection.4 In this paper we compare the analytical properties of 4-iodobutaneboronic acid (I) with that of the most useful of the substituted aromatic boronic acids, 2,4-dichlorobenzeneboronic acid (11). Exper:imental Apparatus troller, flash vaporisation injector (250 "C) and detector oven (300 "C) was used. For FID studies a Perkin-Elmer, Sigma 2, gas chromatograph with a constant flow con- *For details of Part I11 see reference list, p.86.Jawary, 1979 SHORT PAPERS 83 OH / I CHzC H$ H&H 2B \ OH HO\ /OH 0 Cl I I I 4-lodobutaneboronic acid 2,4-Dichlorobenzeneboronic acid For ECD studies a Victoreen 4000 gas chromatograph with a custom-designed ECD was empl~yed.~ The ECD contained a 30-mCi nickel-63 source and was operated in the pulse mode with a pulse width of 4 ps and a pulse period of 2000 ps. Chromatographic Conditions All separations were carried out with a nickel column (90 x 0.2 cm i.d.) packed with 1% OV-17 on Gas-Chrom Q (100-120 mesh) and a nitrogen flow-rate of 60mlmin-l. The derivatives of the bifunctional compounds were separated isothermally and the conditions are given in Table I.For monitoring the synthesis of the boronic acids, aliquots were removed from the reaction flask and an excess of pinacol was added. The pinacol boronates were separated by tempera- ture programming from 70 to 160°C at 8 "Cmin-1 on the above column. The elution temperatures for the 4-chlorobutaneboronate, 4-iodobutaneboronate and 1,4-butane- diboronate of pinacol were 93, 112 and 137 O C , respectively. Reagents All chemicals were of reagent grade and were obtained from a variety of sources. 4-Iodobutaneboronic acid and 2,4-dichlorobenzeneboronic acid can be obtained from Lancaster Synthesis, Lancaster. 4-Iodobutaneboronic acid was prepared for the first time in this laboratory as described below. For the preparation of the 4-chlorobutane Grignard reagent, anhydrous tetrahydrofuran (350 ml), 4-bromochlorobutane (85 g, 0.5 M), magnesium turnings (12.2 g, 0.5 M) and a crystal of iodine were heated under an atmosphere of nitrogen.Upon initiation of a spontaneous reflux, the reaction flask was plunged into an ice - water bath and the stirring continued at 0 "C until nearly all of the magnesium had been consumed and the reaction had subsided (approximately 0.5 h). Conversion of the Grignard reagent into the boronate Grignard complex with trimethylborate (52 g, 0.5 M) was carried out in an analogous manner to that described previously for aromatic boronic acid^.^^^ The Grignard complex was hydrolysed with 6 N hydrochloric acid (250 ml), the ether phase collected and the aqueous phase extracted with butan-1-01 (2 x 50 ml).* The organic phases were combined and the solvents removed in vacuo.The dibutyl 4-chlorobutaneboronate was obtained by vacuum distillation (boiling range 125-127 "C at 3.5 mmHg; yield 44.6 g, 36%) (literature value6 120-123 "C at 1.0 mmHg). The 4-chlorobutaneboronic acid was obtained by hydrolysis using an excess of 6 N hydrochloric acid with removal of butan-1-01 as its azeotrope in vacuo. The acid was recovered by vacuum filtration and dried (yield 21.4 g, 90%; melting range 143-146 "C. NMR: ClCH,, triplet 3.55 p.p.m. MS [70 eV, 150 O C , anhydride (ClC,H,BO),]: m/e 305 [M - CH,Cl], 0.1%; m/e 263 [M - C,H,Cl], 0.2%; m/e 227, 0.4%; m/e 149, 1.4%; m/e 128 [ClC,H,BO], 1.0%; m/e 56 [C,H,], 100%. Pinacol derivative (boiling range 88-89 "C at 2.5 mmHg), MS (70 eV): m/e 183 [M - Cl], 1%; m/e 169 [M - CH2C1], 16%; m/e 155, 2%; m/e 142, 2%; m/e 129 [M - C,H,Cl], 27%; m/e 113, 6%; m/e 98, 17%; m/e 85 [C,H,O], 66%; m/e 70, 18%; mle 59,44%; mle 55,28%; m/e 43 [C,H,O], 100~o}.The 44odobutaneboronic acid was prepared by refluxing overnight 4-chlorobutaneboronic acid (21.4 g) and sodium iodide (60.0 g) in anhydrous acetone (300 ml). The solution was reduced to approximately one third of its volume on a rotary evaporator and filtered while IR: Y (BOH) 3220 cm-l. broad. * The addition of water may be required for phase separation.84 SHORT PAPERS Analyst, Vol. 104 still warm, the filtrate concentrated in vacuo and the residue triturated with a warm acetone - hexane solution and filtered to remove the .remaining salts. The residue from the filtrate was recrystallised from aqueous methanol to give 4-iodobutaneboronic acid (yield 30.1 g, 84%; melting range 96-99 "C.IR: v (BOH) 3270 cm-l, broad. NMR: ICH,, triplet 3.21 p.p.m. RilS [70 eV, 150 "C, anhydride (IC,H,RO),]: m/e 503 [M-I], 27%; m/e 447 [M-C,H,I], 2.2%; m/e 391, 2.2%; m/e 375, 8.0%; m/e 319 [M-C4HsI,], 16.3%; m/e 291, 21.8%; m/e 247, 7.8%; m/e 191, 4.7%; mle 1.55, 4.8%; m/e 109, 17%; m/e 83, 19%; m/e 69, 11% ; m/e 55 [C,Hll], 100~o. Pinacol derivative (boiling range 110-111 "C at 3.1 mmHg), MS (70 eV) m/e 203, 28%; m/e 183 [M-I], 14%; m/e 163, 21%; m/e 131, 22%; nz/e 118, 49%; m/e 96, 32%; m/e 83, 66%; m/e 69, 48%; m/e 59, 73%; in/e 56, 88%; m/e 41 [C,H,] 100 yo >. Preparation of Derivatives For gas chromatography, derivatives were formed by adding equal volumes of 0.1 M solutions of the boronic acid and bifunctional compound in tetrahydrofuran to 1 .O-ml Reacti- vials with PTFE screw-cap liners followed bly a period of brief mixing on a vortex mixer.The solutions were allowed to stand for 15 min at room temperature prior to injection. Results and Discussion The introduction of an electrophore into the boronic acid group presents several problems, especially the selection of the electrophore itself and the matching of this selection to the chemical properties of boron. Also to be coiisidered are the chromatographic properties of the derivative (ie., volatility, peak shape, thermal stability, etc.). The ECD is selective for an ill-defined range of electronegative and conjugated systems to which it shows a response variation extending over a range of about 106-fold.7 Of the non- aromatic electrophores, the halogen atoms are the most convenient for the preparation of volatile derivatives.Their response towards the ECD increases in the order I > Br > C1 >F, which is, of course, the reverse order of the volatility of their compounds. The ECD response also increases synergistically with multiple halogen substitution on a single carbon atom. In terms of volatility of derivatives, this approach to providing a high detector response is feasible only with chlorine and fluorine substituents. Alkyl groups with multiple fluorine substituents are particularly attractive from the volatility point of view, as the boiling-points of their compounds are increases little over those of the hydrocarbon analogues with the same number of carbon atoms, in spite of the increase in relative molecular mass8 However, fluoralkyl compounds respond poorly to the ECD unless the possibility exists for some further interaction (stabilisation of the captured electron) as in the heptafluoro- butyrates, for example (fluoroalkyl chain and ester carbonyl group).The 3,3,4,4,5,5,5- heptafluoropentyldimethylsilyl ethers responld only poorly to the ECD.S Features of the chemistry of alkyl boron compounds that are important to this study are the thermal migration of halogens to boron, with olefin elimination for alkyl boron compounds with halogen substituents on 01, /3, y carbon atoms (reviewed by OnaklO), and the neighbouring group effect observed with the same compcunds, which results in diminished hydrolytic stability (reviewed by Mattesonll) .These properties are not exhibited by A-substituted alkyl boron compounds.11~12 Consequently, it was considered that the best compromise between derivative stability (thermal and hydrolytic), chromatographic volatility and response to the ECD would be represented by the derivatives formed with 4-iodobutane- boronic acid. Based on our experiences of different approaches to the synthesis of 4-iodobutaneboronic acid, the most convenient reaction is the halicle ion exchange between 4-chlorobutaneboronic acid and sodium iodide. Attempts to prepare the 4-iodobutaneboronic acid directly with 1,4-diiodobutane resulted in the preferential formation of the bis-Grignard reagent under all conditions.The use of tetrahydrofuran as solvent (preferable to diethyl ether) and carrying out the reaction at ice-bath temperatures, minimises the formation of the bis-Grignard reagent with 4-bromochlorobutane. Under these conditions the yield of 4-chlorobutane Grignard reagent is high (>80%) and after the formation of the dibutyl boronic acid esters, purification of the products can be achieved by vacuum distillation through a short columnJanuary, 1979 SHORT PAPERS 85 packed with glass beads. The halide ion-exchange reaction can be forced to completion when the boronic acid is employed but not with the dibutyl esters, and this avoids a difficult separation problem (dibutyl 4-chlorobutaneboronic acid ester, boiling range 125-127 "C a t 3.5 mmHg, and dibutyl 4-iodobutaneboronic acid ester, boiling range 133-136 "C at 3.2 mmHg).A representative series of bifunctional compounds was selected to investigate the range of application and chromatographic properties of the new reagent. The distant position of the iodine substituent with respect to boron had little effect on the reactivity of the boronic acid group, neither was it displaced in solution under conditions required for derivative formation, nor under the conditions and temperature required for gas chromatography. In keeping with our observations on the use of aromatic boronic acids, chromatographically stable derivatives were not formed with propane-l,3-dithiol, methylguanidine, ethylene- diamine, 3-aminophenol, malonic acid or pentane-l,5-di01.~3~ The aromatic carboxylic acids either failed to react or produced derivatives that degraded rapidly on standing and are of limited use for trace analysis.Neither of the 4-halobutaneboronic acids formed a stable derivative with propane-l,3-diamine but did produce a derivative peak with 3-hydroxy- propionic acid in contrast to 2,4-dichlorobenzeneboronic acid. All other compounds pro- duced stable derivatives with good gas-chromatographic peak shapes ; the results are summarised in Table I. The 4-iodobutaneboronates are significantly more volatile than the 2,4-dichlorobenzeneboronates (approximately 2-3.5-fold) and are the most volatile of the electron-capturing boronic acid reagents prepared to date.2J TABLE I RETENTION TIME DATA FOR BIFUNCTIONAL COMPOUNDS AS THEIR BORONATE DERIVATIVES 4-Chlorobutane- 4-Iodobutane- 2,4-Dichlorobenzene- Column Compounds boronate boronate boronate temperature/"C Ethylene glycol . ... 0.05 0.17 0.60 120* Pinacol . . .. .. 0.09 0.26 0.70 120* Pentane- 1,S-diol . . .. 0.10 0.31 1.15 120* Butane-1,3-diol . . . . 0.21 0.60 2.02 120* Lactic acid . . . . . . 0.13 0.45 1.14 120* 3-Aminopropan-1-01 .. 0.13 0.48 1.21 120* 2-Aminobutan-1-01 . . .. 0.14 0.45 1.18 120* Propane-1,3-diamine . . - - 1.36 120* Catechol . . . . ,. 0.36 1 .oo 2.54 l6Ot cis-Cyclohexane- 1,S-diol . . 0.29 0.87 2.64 150t o-Phen ylenediamine . . 0.59 1.47 2.94 200: D,L-Mandelic acid . . .. 0.52 1.28 2.60 200: Salicylic acid .. . . 0.52 1.30 2.70 200t Anthranilic acid . . .. - - 6.90 200: * Internal standard C,,, Rt = 9.6 min.t Internal standard C,,, Rt = 3.7 min. $ Internal standard CZ4, Rt = 1.9 min. The response of the ECD is markedly temperature dependent, and is an important par- ameter in optimising the detector sensitivity.13 Most derivatives fall into one of two classes, non-dissociative or dissociative, illustrated below for the simplified example of the molecule AB14 : AB + e- s AB- AB + e- -+ A- + B- non-dissociative dissociative The bond-breaking process (dissociative mechanism) is favoured by high detector tempera- tures and so is the detector response for derivatives of this type. The converse is also true and non-dissociative type compounds are best determined at low detector temperatures. To gain some insight into the mechanism of the ECD response and to establish the optimum detector temperature for analysis, the 4-iodobutaneboronate and the 2,4-dichlorobenzene- boronate of pinacol were chromatographed over a range of detector temperatures. The86 SHORT PAPERS Analyst, Vo,?.104 results are summarised in Fig. 1, in the form. of a graph of l.nAT3/2 versus 1/T ( A is the peak area for a constant mass of derivative and T is the absolute detector temperature). The slope of the lines indicates that the electron-capture mechanism is dissociative (at least up to 325 “C) for both derivatives and the optimum detector temperature for maximum response is 325 “C. The detection limits for pinacol were established as 16 x 10-l2 g for the 4-iodo- butaneboronate and 2 x g for the 2,4-dichlorobenzeneboronate. 9.5 - ’ 1.5 1.75 2.0 I T x 103 Fig.1. Graph of In AT3I2 uersus 1/T for: A, 2.4-dichlorobenzene- boronate; and B, 4-iodobutane- boronate derivative of pinacol. Conclusions The 4-iodobutaneboronates and the 2,4-dichlorobenzeneboronates are useful comple- mentary reagents for the trace analysis of bifunctional compounds by gas chromatography with electron-capture detection. Their range of reactivity is similar, although the 2,4- dichlorobenzeneboronates are probably preferable for amine-containing compounds. When maximum sensitivity is required, the 2,4-diclhlorobenzeneboronates should be selected but when a more volatile derivative is needed, then the 4-iodobutaneboronates are preferred. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. References Darbre, A,, in Blau, K., and King, G. S., Editors, “Handbook of Derivatives for Chromatography,” Poole, C. F., Singhawangcha, S., and Zlatkis, A, Chromatographia, 1978, 11, 347. Poole, C. F., Singhawangcha. S., and Zlatkis, A, J . Chromat., 1978, 158, 33. Poole, C. F., Singhawangcha, S., Zlatkis, A., and Morgan, E. D., J . Nigh Resolution Chromat. Fenimore, D. C., and Davis, C. M., J . Chromat. Sci., 1970, 8, 519. Miginiac, L., and Blais, J., J . Organometall. Chem., 1971, 29, 349. Poole, C. F., Chemy Ind., 1976, 479. Chambers, R. D., “Fluorine in Organic Chemistry,” John Wiley, New York, 1973, pp. 140 and 274. Morgan, E. D., and Poole, C. F., J . Chromat., 1974, 89, 225. Onak, T., “Organoborane Chemistry,” Academic Press, New York and London, 1975, p. 124. Matteson, D. S., Prog. Boron Chem., 1970, 3, 117. Hawthorne, M. F., J . Am. Chem. SOC., 1969, 82, 1886. Poole, C. F., J . Chromat., 1976, 118, 280. Wentworth, W. E., and Chen, E., J . Gas Chroniat., 1967, 5, 170. Heyden, London, 1977, pp. 262-316. Chromat. Commun., 1978, 1, 96. NOTE-References 2, 3 and 4 are to Parts I, 11 and 111 of this series, respectively. Received Julie 6th, 1978 Accepted August 15th, 1978

ISSN:0003-2654    

DOI:10.1039/AN9790400082

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

January, 1979 SHORT PAPERS 87 Spectrophotometric Determination of Silver with Ammonium 2-Cyano-3-iminodithiobutyrate Motomu Muraoka and Tatsuo Yamamoto and Tatsuo Takeshima Department of Chemistry, Faculty of Science, Josai Ufliversity, Keyaki-Dai, Sakado-Shi, 350-02, Japan Department of Chemistry, Faculty of Science, Chiba University, Yayoi-Cho, Chiba-Shi, 280, Japan Keywords : Silver determination ; spectrophotowetry ; ammonium 2-cyano-3- iminodithiobutyrate ; salver complex Dithizone (diphenylthiocarbazone)lY2 and rhodanine derivativesl~~ have long been used for the spectrophotoinetric determination of silver ions, although various other reagents have also been These reagents contain a thiocarbonyl group. Many other sulphur- containing reagents, such as 4,4’-bis (die t hylamino) t hiobenzophenone ,6 sodium diet hyldithio- carbamate2J3p9 and tetraethylthiuram disulphide2 have also been reported for the spectro- photometric determination of silver.We have found that ammonium 2-cyano-3-iminodithiobutyrate (CIDT) is also an excellent reagent for the determination of silver. The reagent reacts sensitively and fairly selec- tively with silver ions in an aqueous solution to form a brillant pink - red complex com- pound. The advantages of this method are that the reagent does not absorb at the point of maximum absorbance of the silver - CIDT complex and the range of determination is fairly wide (0.4-10 pg ml-l), The free acid of CIDT is also sensitive to silver ions, but it could not be used for the present purpose because it is insoluble in water.The silver - CIDT complex is insoluble in all common organic solvents and therefore cannot be extracted with solvents that are not miscible with water, such as chloroform, carbon tetrachloride and benzene. All other homologues of CIDT were insensitive to silver. The effects of pH and of various ions on the absorbance of the silver - CIDT system have been studied and an attempt has been made to elucidate the stoicheiometry of the system. In this paper, we describe a spectrophotometric determination of silver with this reagent. CIDT can also be used for the identification of silver ions in qualitative analysis. The reagent is soluble in water and therefore is easy to use. Experimental Apparatus A Hitachi, Model EPS-3T, recording spectrophotometer was used for measuring the absorp- tion spectra and a Hitachi, Model 101, spectrophotometer was used for the determination of silver.Reagents All chemicals used were of analytical-reagent grade and distilled and de-ionised water was used. Preparation of CIDT reagent. CIDT was prepared freshly from /3-iminobutyronitrile and carbon disulphide in the presence of sodium tert-pentyl oxide.lO The crude free acid, 2-cyano-3-iminodithiobutyric acid, was converted into its ammonium salt (CIDT) by passing ammonia gas into a solution of the acid in diethyl ether, and the CIDT obtained was purified by recrystallisation from ethanol - hexane (1 + 1) and stored in a brown bottle. Pure CIDT contains 7.1% of water after being dried over silica gel for 2 d. Reagent solution. A solution containing 50 mg of reagent in 100 ml of water was prepared freshly before use.Silver rtitrate solution. A 2.15 X lo-* M solution of silver nitrate was prepared and stored in the dark. Buffer solution. Michaelis buffer solution was prepared by adding 200 ml of 0.1 M sodium acetate solution to 800 ml of 0.1 M acetic acid. Solutions of lower concentrations were prepared by dilution of this solution.88 SHORT PAPERS Analyst, Vol. 104 Procedure Transfer 10.0 ml of an aqueous solution containing 11-330 pg of silver into a 25-ml calibrated flask and dilute with water to approximately 15 ml, add 2.5 ml of sodium acetate - acetic acid buffer solution in order to adjust the pH to 4.0-6.0 and then add 2.5 ml of CIDT reagent (50mg of CIDT in 100ml of water). Dilute the mixture to volume with water.Allow the mixture to stand for 10 min and then measure the absorbance at 565 nm against a reagent blank solution prepared under similar conditions. Results and Discussion CIDT produced different colours with various metal ions. The visual detection limits and the colours of the CIDT-metal systems are given in Table I. The sensitivity of CIDT to nickel(I1) was inferior to that of 2-aminocyclopent-l-ene-1-dithiocarboxylic acid, which has a sensitivity to this ion superior to that of dinnethylg1yoxime.ll TABLE I VISUAL DETECTION LIMITS AXD COLOURS OF COMPLEXES OF AMMONIUM 2-CYANO-3-IMINODI'~HIOBUTYRATE AND METAL IONS Ion .. .. 2(1i). . . .. Ni(I1) . . .. Pb(I1) . . . . CU(I1) . . .. Au(II1) . . .. Hg(I1) .. .. Fe(II1) . . .. Visual detection limit/pg ml-1 0.2 0.2 0.2 0.4 0.6 1 5.5 9 Colour Pink - red Yellow Violet Yellow Brown Yellow Yellow Green Absorption graphs for the silver - CIDT complex and CIDT in water are shown in Fig.1. The complex showed a maximum absorbance at 565 nm. The molar absorptivity is 1.27 x 104 1 mol-l cm-l. The effect of pH on the absorbance of the silver - CIDT complex was examined (Fig. 2). The absorbance did not change between pH 4 and 9. The absorbance at a pH below 1.5 could not be measured because of the precipitation of the silver - CIDT complex and silver was precipitated as hydroxide above pH 10.8. 1 .o 0.8 W 0.6 -E 8 n a 0.4 0.2 '0 400 450 500 550 600 650 Wavelengthhm Fig. 1. Absorption spectrum of silver - CIDT complex. A, Absorption spectrum of silver - CIDT complex veysus reagent blank, [Ag] = 9.24 x M, and B, absorption spectrum of CIDT (0.004%) in water.January, 1979 SHORT PAPERS 89 0.8 1 I (0 3 6 9 12 PH Fig.2. Effect of pH on absorbance of silver - CIDT com- plex, [Ag] = 8.62 x M. The acidity of the solution was adjusted by addition of sulphuric acid, sodium acetate - acetic acid buffer, sodium carbonate - sodium hydrogen carbonate buffer or sodium hydroxide. The pH values given are the readings obtained with a glass electrode immediately before the addition of the CIDT. The silver - CIDT system follows Beer’s law at the absorbance maximum of 565 nm over the concentration range of 0.4-lo pug of silver per millilitre of solution. The range was extended to 14 pg ml-l when the absorbance of the system was measured at 560 nm.The stability of the silver - CIDT complex remained unchanged for 2 h, but the colour began to fade after 3 h. The composition of the silver - CIDT complex was studied by the molar ratio method. A 2.29 x M silver solution and a 1.09 x 10-3 M CIDT solution were used; the final silver ion concentration was 9.54 x M. Fig. 3 indicates that a 1 : 1 complex is formed. The rising portion of the molar ratio graph does not extrapolate back to zero. This is attributable to an excess of silver ions, which interfere with the formation of the silver - CIDT complex or denature the complex. The shape of the graph was also the same as that obtained when silver acetate was used. It appears from the nature of silver and the range of absorbance by the chromophoric groups in CIDT reagent that the species which brings about the coloration is not the silver salt, silver 2-cyano-3-iminodithiobutyrate, but the silver - CIDT complex.Silver diethyldithiocarbainate8~~ does not show an absorbance above 400 nm. Two homologues of CIDT, 2-cyano-3-imino-3-phenyldithiopropionic acidlo and 2-aminocyclopent-1 -ene-l-dithiocarboxylic acid1lYl2 produce only a yellow colour when Mol CIDT per mol of si!ver Fig. 3. Molar ratio plot for silver - CIDT complex. [Ag] = 9.54 x M.90 SHORT PAPERS silver ions are added. Further, silver nitrate solution produced a yellow colour momentarily when CIDT reagent was first added, which then turned pinkish red. From the above results, coupled with the fact that the methyl ester of CIDT does not exhibit a coloration with silver or any other metal ions, it can be concluded that the silver - CIDT complex has the compo- sition Ag,(CIDT),, which has a twelve-membered ring structure because the amino and dithiocarboxyl groups in the enamine form of CIDT can be in the trans positions.2-Aminocyclopent-l-ene-l-dithiocarboxylic acid cannot form a corresponding complex with silver ions because the amino and dithiocarboxyl groups are in the cis positions. Although the amino and dithiocarboxyl groups in the enamine form of 2-cyano-3-imino-3- phenyldithiopropionic acid are in the trans positions, the compound is insensitive to silver ions as the steric hindrance by the phenyl group makes the formation of a complex with the ion impossible. M silver solution and a 1.000-cm cell.When present in concentrations of 400 p.p.m., Na+, K+, Fe2+, U022+, SO,2-, NO3-, EDTA2-, tartrate, borate, thiosulphate, chlorate and acetate did not interfere, but M@+, Ba2+, Mn2+, AP+ and Cr20,2- interfered slightly, Addition of 125 p.p.m. of Zn2+ precipitated the silver - CIDT complex, but 35 p.p.m. of Zn2+ did not. The main inter- ferents are Fez+, Co2+, Ni2+, Cu2+, Pb2+, Hg2+, Au3+, Cl-, CN- and SCN- ions. On addition of EDTA as the masking agent (at levels of 50400 times the concentration of the foreign ions) to the solution containing interfering foreign ions such as Ni2+, Co2+, Pb2+ and Fe3+, the interference was suppressed and the silver - CIDT complex formed quantitatively. Copper(I1) ions, in the presence of EDTA, caused the silver - CIDT complex to precipitate; mercury(I1) ions could not be masked by EDTA.The effects of various ions were investigatedL by using a 8.40 x 1. 2. 3. 4. 6. 6. 7. 8. 9. 10. 11. 12. References Sandel, E. B., “Colorimetric Determination of Traces of Metals,” Third Edition, Interscience, New Koch, 0. G., and Koch-Dedic, G. A., “Handbuch der Spurenanalyse,” Springer, Berlin, 1964, p. 273. Snell, F. D., and Snell, C. T., “Colorimetric Methods of Analysis,” Volume 2A, Van Nostrand, Dagnall, R. M., and West, T. S., Talunta, 1964, 11, 1533. El-Ghamry, M. T., and Frei, R. W., Analyt. Chem., 1968, 40, 1986. Cheng, K. L., Mikrochim. Acta, 1967, 820. Prazybylowicz, E. P., and Zeuhlke, C. W., in Kolthoff, I. M., and Elving, P. J., Editors, “Treatise Sudo, E., J . Chem. SOC. Japan, 1952, 73, 626. Bode, H., 2. Analyt. Chem., 1956, 144, 165. Muraoka, M., Yamamoto, T., Yamaguchi, S., Tonosaki, F., Takeshima, T., and Fukada, N., J . Chem. Soc., Perkin Trans. I , 1977, 1273. Yokoyama, M., and Takeshima, T., Analyt. Chem., 1968, 40, 1344. Takeshima, T., Yokoyama, M., Imamoto, T., Akano, M., and Asaba, H., J . Org. Chem., 1969, 34, York, 1959, p. 802. Princeton, N.J., 1959, p. 23. on Analytical Chemistry,” Part 11, Volume 4, Interscience, New York, 1966, p. l., 730. Received July 3rd, 1978 Accepted August 14th. 1978

ISSN:0003-2654    

DOI:10.1039/AN9790400087

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

A lzalyst , Jaizuary , 1979 Book Reviews 91 RADIOCHROMATOGRAPHY. THE CHROMATOGRAPHY AND ELECTROPHORESIS OF RADIOLABELLED COMPOUNDS. By T. R. ROBERTS. Journal of Chromatography Library, Volume 14. Pp. x + 174. Amsterdam, Oxford and New York: Elsevier. Distributed by Elsevier North-Holland in the USA and Canada. 1978. Price 539.95; Dfl90. In this book the author has set out to describe and discuss the various radiochromatographic and radioelectrophoresis methods. The book is divided into eight chapters, which include an introduction to the use of radioisotopes in the laboratory, radioactivity detectors used in chromato- graphy, and the technique as used in paper, thin-layer, column and gas - liquid chromatography and electrophoresis. Each of the chapters covering the various techniques is arranged attractively, with an intro- duction and a section on the development of the type of chromatography in question, followed by the selection of a method for a particular application.The chapter on radio-electrophoresis reviews paper, thin-layer and polyacrylamide gel electrophoresis methods. Some applications of the methods available are given in most of the chapters and there is a final section devoted to miscellaneous applications. References are to be found a t the end of each chapter, and safety aspects are not forgotten, The radioactivity detectors that have been used in radiochromatography are discussed- ionisation detectors (proportional and Geiger - Muller counters), scintillation counters, auto- radiography, spark chambers and semiconductor detectors.Examples are given of those available commercially. Applications are given of studies in the fields of pesticide and drug metabolism, biochemical separations, radiosynthesis and radiochemical purity determinations, among others, and the chapter on miscellaneous applications of radioisotopes includes separations, for example, in soil leaching studies and in the continuous monitoring of radioactivity in animals. The book is the 14th volume in the Journal of Chromatography Library and is a worthy addition. I t is a useful review work with something under 400 references and the author, who has specialised in work in the pesticides field, has made it easy and interesting to read in addition to being informative. D. SIMPSON LABORATORY HANDBOOK OF PAPER AND THIN-LAYER CHROMATOGRAPHY.By J. GASPARIC and J . CHURACEK. Ellis Horwood Series in Analytical Chemistry. Pp. 362. Chichester: Ellis Horwood. New York, London, Sydney and Toronto: John Wiley. Distributed by John Wiley in Australia, New Zealand, South- east Asia, Europe and Africa and by Halsted Press in North and South America and the rest of the world. 1978. Price LlS. Translation Editor, R. A. CHALMERS. I t is interesting, albeit a little surprising, to see yet another book about paper and thin-layer chromatography. This one is described as a handbook and its authors are members of the academic field in Czechoslovakia-Dr. GaspariE is Head of the Department of Physical Chemistry in the Faculty of Pharmacy at Charles University, Hradec KrAlov6, and Dr.ChurAEek is Head of the Department of Analytical Chemistry at the Technical University, Pardubice. Early chapters of the book are given over to the principles and techniques of paper and thin- layer chromatography and cover all the details necessary for the preparation and documentation of chromatograms. Mention is made of qualitative and quantitative techniques, the use of preparative layers and the relationships between chromatographic behaviour and chemical structure. An international list of firms supplying equipment and materials is also provided. All this information is to be found under Part I of the volume. Part I1 covers the applications and mentions over one thousand substances that have been chromatographed. Groups dealt with include hydrocarbons, halogen derivatives, alcohols, phenols, ethers, 0x0 compounds, organic peroxides, carbohydrates, carboxylic acids, lipids, steroids, terpenes, 0- and N-heterocyclic compounds, amines and nitro compounds, hydrazines and related substances, sulphur and organic phosphorus compounds.In addition, mention is made of organometallic compounds, vitamins, antibiotics, alkaloids, synthetic dyes and some inorganic and radioactive substances.92 BOOK REVIEWS Analyst, Vol. 104 The book contains very little in the way of explanation of extractions from, for example, industrial compounds. It might be debatable whether or not a handbook should include these features, and in fairness it should be pointed out that there are over 1200 references in all, where no doubt the reader could obtain more detailed methods. This could well be a very useful volume for a laboratory worker who wishes to look up a particular compound in the index but the reviewer feels that a word of warning should be given when mention is made of toxic products such as aflatoxins, with perhaps a note on how they should be handled (or preferably not handled).Nonetheless the book could be most helpful as an introductory work and a t a cost of around fIl8 for 362 pages might be regarded as reasona'ble value for money a t present prices. D. SIMPSON INELASTIC ELECTRON TUNNELLING SPECTROSCOPY. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE AND SYMPOSIUM ON ELECTRON TUNNELLING, UNIVERSITY O F MISSOURI- COLUMBIA, USA, MAY 25-27, 1977. Springer Series in Solid- State Sciences.Pp. viii + 242. Berlin, Heidelberg and New York: Springer-Verlag. 1978. Price DM58; $29. Edited by T. WOLFRAM. Almost traditionally the development and subsequent exploitation of analytical techniques, in their now multifarious forms, pass from the hands of the physicist to the chemist and then to the analyst. Inelastic electron tunnelling spectroscopy (IETS) since its inception in 1966 has, in my view, reached about half-way along that sequence-I make no predictions as to its future. Nonetheless, the present status of the technique, in virtually all its existing aspects, is contained in this book. These Proceedings, the collected conference papers given by the leaders of the few groups actively involved specifically with the method or very closely related techniques, will theref ore serve admirably as a guide to IETS to all interested.The early work--theory and practice, more recent developments, likely progress and possible applications-are all admirably brought together and summarised. Clearly the book will serve both as an excellent introduction to the technique and as a handy reference for those already actively involved with the method. In summary it provides a unique, very highly sensitive method of electronically monitoring the vibrational modes of molecular adsorbates on a metal oxide surface. The technique has been developed by a number of laboratories for the study of the surface chemistry of such adsorbates on aluminium oxide. More recently applications have included the physi- and chemisorption of hydrocarbons, catalysis by metal particles, detection of trace amounts of organics in air and water and studies of biological molecules and electron damage to such molecules.IETS has also been used to investigate adhesives and work is in progress on the corrosion of aluminium and its alloys. Though as yet less successfully than vibrational molecular behaviour, electronic transitions have also been observed. A word of caution: while the book does fully review the technique it says little about the experi- mental difficulties and practical requirements. Not least of these is the provision of liquid helium. Finally, as a sign of the times, the book for its size is expensive. What then does IETS offer? NORMAN M. D. BROWN DEVELOPMENTS IN FOOD ANALYSIS TECHNIQUES-1. Edited by R.D. ICING. Pp. x f 323. London: Applied Science. 1978. Price i(25. This book is the first of a series that will be devoted to a discussion of recent development in techniques of food analysis. Such a series will be an interesting addition to the bookshelves of food analysts as a reference work giving an initial understanding of particular techniques. Being written in review format it cannot, I think, be considered a basic working aid to the analyst, because although some sections provide detailed. descriptions of equipment, reference elsewhere will need to be made for information on the practical applications of techniques in particular analyses. In addition the dynamic state of food analysis development is likely to date quickly those sections where applications are discussed in greater detail.Of the ten contributions to the book, five (Chapters 4-7, 10) discuss a particular technique,January, 1979 BOOK REVIEWS 93 its uses and equipment and three (Chapters 1, 2 and 9) consider a particular food class and techniques that may be used in its analysis. Of the remaining two chapters, Chapter 8 gives an informative and illustrative insight into the factors that must be considered in the automating of a laboratory. The discussion is based on the contributor’s own experiences and summarises the basic benefits (mostly economic) of such laboratory organisation. Chapter 3, dealing with the role of water in foodstuffs, is, perhaps, out of place in this volume when compared with the subject matter of the other sections. Although undoubtedly of value to the food technologist the thermodynamic, electrical and nuclear behaviour of water and its molecular and sub-molecular components will be of a more limited interest to food analysts.Most of the chapters dealing with particular techniques provide good reviews on the present state-of-the-art and applications. Recent developments are generally discussed well (e.g., capillary columns and head-space analysis) although the chapter on atomic-absorption spectro- scopy is, perhaps, deficient in this respect giving, as an example, no mention of the more recent Teflon bomb sample preparation procedures. The chapters concerned with methods of analysis of particular food classes are all well written leading the reader through, sometimes, detailed discussion on relevant techniques.It would have been useful if the section on the Determination of Nitrogen and Estimation of Protein in Foods could have been expanded to include more information on the determination of individual proteins and protein fractions in view of the current interest in non-meat proteins and calculation of meat contents. This is, in summary, a readable and enjoyable (apart from the price) volume, which might have been improved if not presented as ten discrete contributions. Areas of overlap occur between sections dealing, on the one hand, with a technique with reference to a particular food component and, on the other hand, a food component with reference to a particular technique. However, most contributions have provided a very full list of references and, if the volume is used as a starting point, these will guide the reader to sources of more detailed information.R. WOOD ANALYTICAL NOTES: A SUMMARY OF INORGANIC METHODS OF CHEMICAL ANALYSIS. By H. J. BONIFACE. Pp. 64. Wolverhampton : Sigma Technical Press. 1978. Price k3.50 (softback). The book is the distillation and concentration of a large number of years of experience that the author has gained as an industrial analytical chemist and deals with the determination of some thirty industrially important elements at both the major and trace levels. The elements are arranged in alphabetical order starting with aluminium and finishing with the combination of zirconium and hafnium. Each element receives two pages (as a single sheet) of attention, the format being identical for each element.Each sheet contains information on the preparation of standards, reactions that are used in the analysis, methods of separation for the element of interest from others, then methods of determination (gravimetric, titrimetric, molecular spectro- photometric, atomic-absorption spectroscopic, polarographic, spectrofluorimetric and gas- chromatographic methods) followed by applications of the methods and references. What is a little surprising in view of their industrial usage, is that emission spectrometry (using for example arcs) and X-ray fluorescence methods are not included. Is such a book useful? The reviewer believes yes; in fact while reading it, he used the book to answer a question on the telephone. The question was, “How can I determine sulphur in leaves ?” So many scientists use analytical chemistry, especially with the popularity of instruments, but who have little breadth of experience in the variety of elements or matrices in which they are encountered that a quick reference book of this type may well be extremely valuable.There are notable exceptions in the elements covered, e.g., mercury is not included, which is surprising in view of the current analytical interest in the element. The book is reasonably well packaged; there are minor errors, but that is only to be expected with the volume of information presented in such a slim volume. It can be recommended for analytical laboratories, especially those receiving enquiries for procedures from other scientists.G. NICKLESS94 BOOK REVIEWS Analyst, Vol. 104 DEVELOPMENTS IN CHROMATOGRAPHY-1. Developments Series. Edited by C . E. H. KNAPMAN. Pp. x + 245. London: Applied Science. 1978. Price L15. Persumably the present volume is the firsit of a projected series covering all aspects of the development of chromatographic methods, although the Preface to this volume is brevity itself. However, there are six such chapters each written by a single author who is an accepted authority on the particular topic; the chapters are fairly well balanced as far as length is concerned, each being about 40 pages long, and the bias of the book is towards gas chromatography. The subjects covered range from the fundamentals of the technique, i.e. , solute - solvent interactions through to the now accepted and demanded applications of chromatographic methods, i.e., to continuous refining studies and forensic science.The chapter on the characterisation of solute - solvent interactions in GLC is in its logical position of being first, as it is the exploitation of this interaction that allows separations to be achieved. The chapter discusses interaction forces, and the approaches that have been adopted to evaluating these forces leading logically to the possible relationship between activity coefficient and structure. In turn we progress to stationary phase classifi cation, where the most interesting feature is the possible substitution of fully hydrogenated Apiezon M in place of squalane as the non-polar standard in the well known McReynolds classification.If this substitution is satis- factory then a modified list of preferred phases for the observation of rentention data is near. Finally, the chapter is completed with a section discussing those stationary phases showing special selectivity ; metal complexes, bentonites and liquid crystals all receive attention. The second chapter describes the developments that have taken place over the last 20 years in taking analytical-scale chromatography into the preparation and even production-scale process, especially for the continuous separation of mixtures. The section on moving column systems is particularly interesting because these systems seem to be the most successful so far suggested. Perhaps the third chapter should have followed directly after Chapter 1, in that it discusses in great detail the gas-chromatographic separation of isomers differing only in molecular structure.Besides H-bonding and the “ortho effect,” separations also depend to a great deal on weak reversible metal - solute complexes. The detailed work that has “exploited” steric effects and molecular shapes of solutes is also included. There could be said to be some overlap with Chapter 1. The most conventional chapter is the fourth, which reviews gas-chromatographic detectors and the author has wisely limited his remarks to some six types of detectors, indeed one could say the most popular of their types today. The detectors in which no major developments have been made in recent years are omitted. However, discussion is also made of detector response and base-line noise.The fifth chapter is concerned with gel-permeation liquid chromatography and summarises very ably the various theories of the technique and the methods available for the calibration of GP columns. There is included a full detailed treatment of the procedure needed to derive the relative molecular mass distribution of a polynneric sample via GPC. The chapter is completed by a timely section on the practical aspects of GPC. The last chapter may again be called a classical paper where the chromatographic developments in forensic science and the various techniques are discussed in great detail. Of specific interest are sample storage and preparation as well a s modern liquid chromatography, which has an invaluable number of applications in this area, but obviously its full potential and possible range of operations has not yet been reached.Obviously the price is a disadvantage to the private owner but the book should be available in research labora- tories and major libraries. A good start to a series: it holds out the promise of more good to come. G. NICKLESS The book is well presented, has clear diagrams and many valuable references. ATMOSPHERIC POLLUTION 1978. Edited by MICHEL M. BENARIE. Proceedings of the 13th International Colloquium, Paris, France, April 25-28, 1978. Studies in Environmental Science I . Pp. xii + 291. Amsterdam, Oxford and New York: Elsevier. 1978. Price $47.75; Dfl105. This book is the first of a series “Studies in Environmental Science,” which will include mono- graphs, multi-author works and conference proceedings concerned with some aspect of the environment or an associated problem.The volume reviewed contains 53 papers selected fromJanuary , 1979 BOOK REVIEWS 95 the 80 presented at the 13th of a series of biennial colloquia and follows a similar pattern to that published after the 12th Colloquium (reviewed, Analyst, 1977, 102, 987). One significant difference is that all of the papers are in English and printed in a more uniform format. The papers included cover all aspects of air pollution except legal and economic, although there is a tendency to concentrate on engineering applications or, as the Editor states in the Preface, “how-to-do” rather than “why.” This is in keeping with the current trend and suggests that the sponsors of the work described apparently prefer products rather than insight. To select and publish such a comprehensive collection of papers within about three months of a conference is no mean task and all concerned are to be congratulated on their efforts.The book is well produced, achieves its objectives and will be useful to those who wish to keep abreast of developments in the field of air pollution. The photographs and diagrams are clear; the legends on some of the latter, however, have not always been translated into English, but this in itself is not a serious criticism. A. F. SMITH VIRUSES AND TRACE CONTAMINANTS IN WATER AND WASTEWATER. Edited by JACK A. Pp. xiv + BORCHARDT, JAMES K. CLELAND, WILLIAM J. REDMAN and GORDON OLIVIER. 249. Ann Arbor, Mich.: Ann Arbor Science Publishers. 1977. Price kl8.60. The present volume is a compilation of papers that were presented at a seminar held biannually and intended to familiarise operators and engineers in the water and wastewater industries with the basic information concerning trace organics and inorganics and viruses likely to be present. The first two sections on viruses plus their removal from water and trace organics are almost devoid of analytical methods although analytically derived data are encountered frequently. Of particular interest to analytical chemists may be the sequence of reactions discussing the chlori- nated organic compounds produced in water and sewage systems, especially via the haloform reaction. In a similar vein is the next chapter on the reactions between trace organics in water and ozone.The third section is a little more familiar territory in that it describes the toxicity of heavy metals to aquatic biological forms and to man. Even more familiar is the paper describing the use of atomic-absorption spectrometry in water quality analysis where the instrumental require- ments, flame atomisation procedures, potential interferences, use of solvent extraction, graphite furnace atomisation, hydride generation and flameless determination of mercury are all described. The remainder of the section discusses the methods for the removal of heavy metals from water. Section IV is biased towards the Standards that American workers have to operate to or under. Although the philosophy is relevant, the numbers and data are probably not.Thus I doubt if this volume, although of great interest to the specialist water engineer, will be of much further interest to analytical chemists, However, as with all these Ann Arbor Science books, it is well produced and most clearly set out, although for the price charged it should be. G. NICKLESS FOURIER TRANSFORM INFRARED SPECTROSCOPY. APPLICATIONS TO CHEMICAL SYSTEMS. Volume Pp. viii + 311. New York, I. San Francisco and London: Academic Press. 1978. Price $25; L16.25. Edited by JOHN R. FERRARO and LOUIS J. BASILE. This book consists of seven chapters, each of which is a self-contained review of the following topics: (l), Matrix Isolation Studies with FT - IR; (2), Applications of FT - IR to Synthetic Polymers and Biological Macromolecules ; (3), Infrared Emission Spectroscopy ; (4), Gas-chromato- graphy and FT - IR; ( 5 ) , High-pressure Infrared Interferometry; (6), Current and Past Research in Far Infrared Interferometry; and (7), FT - IR: Applications to National Technical Problems. Each review is written by authors active in that field and while this has not resulted in much overlap, the breadth of treatment is uneven.Chapters 1, 3 and 5 are fairly general introductions to their respective techniques together with summaries of the results obtained up to 1977 using FT - IR spectrometers. Chapter 4 is a narrower but deeper discussion of the sampling constraints in “on the fly” GC - IR. The inter-related factors of GC-column type, infrared-cell volume and path length are covered as well as the advantages of dual-beam FT instruments in overcoming ADC dynamic range problems of single-beam interferometers. Chapter 6 traces the historical96 BOOK REVIEWS Analyst, Vol. 104 development of far infrared spectroscopy and! instrumentation with reference to examples of its application to vapour phase molecular rotations, heavy atom vibrations, crystal lattice vibration modes, ring motions and group torsional vibrations.Results from both dispensive instruments and interferometers are discussed, with the latter naturally predominating. A feature emphasised in a number of the contributions that is not confined to FT - IR instru- ments is the advantages of spectrum subtraction and data manipulation that are possible with digitised spectra. These are especially apparent in Chapter 2 where most of the results discussed could have been obtained with a digitised dispersive infrared spectrophotometer, albeit at the cost of lengthy spectrum accumulation times in some instances.Examples described in this section include obtaining spectra of single phases in heterophase (semicrystalline and amorphous) polymers, the study of fracture mechanisms and the effects of fillers, and also a very brief mention of biological macromolecules. The final chapter surveys those aspects of “national technical problems” where FT - IR has potential application. The problem areas are identified as atmospheric pollution, space explora- tion and energy-related problems, on the basis that the US Government has set up agencies specifically to investigate these areas (EPA, NASA and ERDA). Even though the infrared spectrum of Jupiter’s atmosphere, obtained using a FT - IR instrument flying at an altitude of 12.4 km above the Earth’s surface, is impressive, the pot-pourri of topics presented in this chapter should either have been given more space or omitted altogether.Overall, this is a well produced volume with few errors, but is unlikely to find its way into many analysts’ personal libraries. C. P. RICHARDS TREATISE ON ANALYTICAL CHEMISTRY. PART 11. ANALYTICAL CHEMISTRY OF INORGANIC AND ORGANICOMPOUNDS. SECTION A. SYSTEMATIC ANALYTICAL CHEMISTRY OF THE ELE- MENTS. Volume 10. ANTIMONY, ARSENIC, BORON, CARBON, MOLYBDENUM AND TUNGSTEN. Edited by I. M. KOLTHOFF and PHILIP J. ELVING with the assistance of ERNEST B.SANDELL. Pp. xviii + 566. New York, Chichester, Brisbane and Toronto: John Wiley. 1978. Price L24.40; $43.85. The other two Parts, I and 111, of this comprehensive three-part treatise on analytical chemistry, deal with Theory and Practice, and Analytical Chemistry in Industry, respectively. I t is unlikely that any up-to-date analyst will be unaware of the periodic release of the various volumes com- prising this series, which, in toto, are planned to cover a very wide field of analytical chemistry and its associated disciplines. To date, it has been my pleasure to review many of the books in this series, in The Analyst, and, after a careful perusal of this one, it would ease my current assignment simply to repeat the favour- able impressions that I have already committed. to print. The analytical chemistry aspects of these six: elements are dealt with in this volume in a (now established) thorough manner ; on this occasion all elements are allocated about the same number of pages, the general presentation of each following a fairly regular pattern. For example, Tung- sten is dealt with under main headings such as Properties of Tungstevz and I t s Compounds, Dissolu- tion of Tungsten, Tungsten Alloys and Tungsten-containing Materials, Separation From Other Elements, Titrimetric Methods, Optical Methods, Radiochemical Methods, Determination in Speci=fic Materials, and Recommended Procedures. As in the earlier books that I have reviewed, the individual subjects in this one are compre- hensively covered by (seven) internationally recognised experts, in addition to the three named Editors. The book is well balanced in the presentation and adequately reinforced with nearly 3 500 references. However, under Carbon, I felt that some of the supporting detail was hardly necessary, and suspected that some readers might be given a false impression of this Section by its reference (p 135) to “A more recent method. . .,” when :in fact, the method referred to appeared in print, in detail, over 20 years ago. Apart from these relatively minor criticisms and the appearance of an odd (obvious) spelling mistake in this, and some of the other Sections, the high technical standard of the series is herein maintained. W. T. ELWELL

ISSN:0003-2654    

DOI:10.1039/AN9790400091

出版商:RSC    

年代:1979

数据来源: RSC