摘要:

ANALYST, NOVEMBER 1991, VOL. 116 1185 Spectrophotometric Determination of Trace Amounts of Copper(i1) Using the Homolysis Reaction of the Copper(i1)-N-pNitrobenzyl- 5,10,15,20=tetra kis( 4=su I p honatop henyl) porp h ine Complex Masaaki Tabata and Kentaro Kaneko Department of Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi, Saga 840, Japan N-p-N itro benzyI-5,10,15,20-tetra kis(4-su Ip honatop henyl)porp hine[p-N02Bz( Htpps)4-] was synthesized and used for the spectrophotometric determination of trace amounts of copper(ii) based on the following reaction: p-N02Bz(Htpps)4- + Cull --+ p-N02Bz[Cu(tpps)]3- + H+ -% Cu(tpps)4- + pN02BzOH. The p-nitrobenzyl group was removed to produce the non-substituted porphyrins by cleavage of the C-N bond (homolysis reaction).The reaction caused a large change in the absorption spectra and was specific for copper(ii) as this ion fitted well into the porphyrin core. Excess of zinc(ii) and palladium(ti) did not show the homolysis reaction. The acid dissociation constants of the porphyrin (-log K,) were found to be 2.51 k 0.02 and 7.70 k 0.02 at 25 "C and an ionic strength of 0.1 mol dm-3 (NaN03). Optimum conditions for the determination of copper(ii) were investigated and the method was applied to the determination of ppb levels of total copper(ii) in a river water sample and in some interstitial sea-water samples from the mud at the bottom of the Ariake Sea. The molar absorptivity was 4.22 x 105 dm3 mol-1 cm-1 and the Sandell sensitivity was 0.15 ng cm-2 of copper(ii).Keywords: Spectrophotometry; copper(ii); determination; porphyrin; homolysis reaction; interstitial sea- water Porphyrins are highly sensitive reagents for the spectropho- tometric determination of trace metals. The molar absorptivi- ties are of the order of several hundred thousand at 400-500 nm (the so-called Soret Band). A number of spectro- photometric and kinetic methods using porphyrins have been described and reviewed by Tabata and Tanaka,' Ishii2 and Yotsuyanagi et al.3 However, the absorption spectra of metalloporphyrins sometimes overlap those of metal-free porphyrins. For example, the absorption maximum of the copper(ii)-5,10,15,20-tetrakis(4-sulphonatophenyl)porphine (H2tpps4-) complex is 413 nm, which is identical with that of the free-base form of H2tpps4-.Hence, measurement of the absorbance was carried out after conversion of the metal-free porphyrin into the acidic form of the porphyrin (H4tpps2-, A,,, = 434 nm) or the lead(ir) porphyrin (Amax = 465 nm).4 This paper describes the use of N-p-nitrobenzyl-5,10,15,20- tetrakis(4-sulphonatophenyl)porphine [p-N02Bz(Htpps)4-] to solve the problem of the change in the absorption spectra for the determination of trace amounts of copper(I1) based on the following homolysis reaction: p-N02Bz(Htpps)'- + CU" -~-NO~BZ[CU(~PPS)]~- + H+ 1 H20 Cu(tpp~)'- + p-NO2BzOH (1) The N-benzylated porphyrin reacted rapidly with metal ions and the N-benzyl group was easily removed to produce the non-substituted porphyrins by cleavage of the C-N bond (homolysis reaction). The debenzylation of the metallo- porphyrin caused a large change in the absorption spectra and the homolysis reaction was specific for metal ions that fitted well into the porphyrin core. Optimum conditions for the determination of copper(i1) were investigated and the method was applied to the determination of trace amounts of copper(I1) in natural waters.Experimental Synthesis of the Porphyrin N-p-Nitrobenzyl-5,10-15,20-tetrakis(4-sulphonatophenyl)- porphine (Fig. 1) was synthesized by the method of Lavallee et al. 5,6 Firstly, tetraphenylporphine (H2tpp) was benzylated so, Fig. 1 N-p-Nitrobenzyl-5,10,15,20-tetrakis(4-sulphonatophenyl)- porphine Ip-N02Bz( Htpp~)~-] by reaction with p-nitrobenzylsulphonium tetrafluoroborate in CH&; the product [N-p-nitrobenzyltetraphenylporphine; p-N02Bz(Htpp)] was then chromatographed on a neutral alumina column using CH2CI2 as the eluent. Secondly, p-N02Bz(Htpp) was sulphonated by heating it with concen- trated sulphuric acid on a steam-bath for 48 h.The product [the fully protonated form of p-N02Bz(H5tpps)] was obtained by slowly adding water to the chilled sulphuric acid until precipitation was complete. The precipitate was washed with acetone and purified on Sephadex LH-20 resin. The purity was checked by proton nuclear magnetic resonance spectroscopy and by the absorption spectra. The yield was 10%. Reagents Sodium nitrate used for adjusting the ionic strength was obtained by recrystallization of analytical-reagent grade sodium nitrate. Other metal nitrates were of analytical- reagent grade and were used without further purification.The metal ion concentration was determined by titration with ethylenediaminetetraacetic acid. The buffer solutions were prepared by the addition of nitric acid or sodium hydroxide to solutions of sodium acetate for pH 4-6, MES [2-(N- morpho1ino)ethanesulphonic acid] for pH 6-7, EPPS "(2- hydroxyethyl)piperazine-N'-3-propanesulphonic acid] for pH7-8.5 and sodium borate for pH 8.5-10 (Wako Pure Chemical Industries, Osaka, Japan). All solutions were1186 ANALYST, NOVEMBER 1991, VOL. 116 prepared in water that had been distilled, de-ionized and then redistilled from alkaline permanganate. Copper(i1) content in the reagents and the water was checked using the proposed method; no copper(i1) was detected. All experiments were carried out at 25 "C.Apparatus Absorption spectra were recorded on a Shimadzu UV-2100 spectrophotometer. The pH values were determined with a Radiometer Ion 85 Ion Analyzer with a combined electrode (GK2401C). A 1.000 x 10-2 mol dm-3 nitric acid solution containing 0.09 mol dm-3 sodium nitrate was employed as the standard hydrogen ion concentration (-log[H+] = 2.000). From the pH meter readings in various hydrogen ion concentrations at an ionic strength of 0.1 mol dm-3 (HN03- NaN03), the pH meter and electrode system were calibrated in terms of -log[H+]. Results and Discussion Determination of the Acid Dissociation Constants of The absorption spectra of p-N02Bz(Htpps)4- in aqueous solutions were measured at various pH values and at an ionic strength of 0.1 rnol dm-3 (NaN03).Absorption maxima were observed at 450 and 436 nm in acidic and alkaline solutions, respectively. The relationship between the apparent molar absorptivities (E) of p-N02Bz(Htpps)4- at 436 and 450 nm and -log([H+]/mol dm-3) at 25 "C is shown in Fig. 2. The change is attributable to the following equilibria: p-NOZBz( Htpps)'- K"3 ~ - N O ~ B Z ( H ~ ~ P P S ) ~ - P-NO~BZ(H~~PPS)~- + H+ (1) Ka2 (I) p-N02Bz(Htpps)'- + H+ and the acid dissociation constants are defined as Ka3 = [~-NO~BZ(H~~~~S)~-][H+I/[~-NO~BZ(H~~~~S)~-], and Ka2 = 4 3 2 I 6 1 - I 0 - E E i n 4 3 i;;j m .o z 2 1 [P-NO2Bz(Htpps)4-][H+]/[p-NO2Bz(H2tpps)3-]. The appar- ent molar absorptivity is given by eqn. (2) where el, ~2 and E~ are the molar absorptivities of [p-N02Bz- (H3tpps)2-], [p-N02Bz(H2tpps)3-] and [p-N02Bz(Htpps)4-], respectively. The apparent molar absorptivity (E) is plotted against -log[H+] in Fig.2. The values of pKa and pKa3 were determined to be 7.70 k 0.02 and 2.51 k 0.d2, respectively; the solid lines in Fig. 2 are the calculated values based on the acid dissociation constants. These pKa values are smaller than those of N-methyl-5,10,15,20-tetrakis(4-sulphonatophenyl)- porphine [N-CH3(Htpps)4-] (8.82 and 3.04)' because of the electron-withdrawing effect of the p-N02Bz substituent. However, these values are very different from the pKa values (4.99 and 4.76) of the non-benzylated or the non-methylated porphyrin (Hztpps4-) .* Alkylation of any of the pyrrole nitrogens will lead to an increase in the distortion of the macrocycle.This in turn leads to an increase in the basicity of a particular pyrrole nitrogen compared with the non-N-alky- lated porphyrin. Reaction of p-NOzBz(Htpps)4- With Metal Ions The reaction of p-N02Bz(Htpps)4- with a number of metal ions (Cd2+, Co2+, Cu2+, Fe3+, Hg2+, Mg2+, Ni2+, Pb2+ and Pd2+) was investigated at pH 8 and 5. A typical change in the absorption spectra is shown in Fig. 3 for the reaction of copper(I1) with p-N02Bz(Htpps)4-. Copper(I1) rapidly forms p-N02Bz[Cu(tpps)]3- ; cleavage of the bond between the p-N02Bz group and the pyrrole nitrogen then occurs to form Cu(tpps)4- and p-N02BzOH by a nucleophilic attack of hydroxide ion. The final absorption spectrum was the same as that obtained for the reaction between copper(i1) and At pH 8, some metal ions (M) such as zinc(i1) and cadmium( xi) reacted withp-N02Bz(Htpps)4- to form metallo- porphyrins of the type p-N02Bz[M( tpps)]3-; however, debenzylation was not observed.Mercury(i1) rapidly formed p-N02Bz[Hg(tpps)]3- and the p-N02Bz group was gradually released. Cobalt(I1) formed Co111(tpps)3- to a small extent when a mixture of cobalt(1i) and p-N02Bz(Htpps)4- was heated and the mixture had been allowed to stand for a long H2tpps4-. 1 0 2 4 6 8 10 -Log[H+] Fig. 2 Plots of apparent absorptivity versus -log[H+] at (a) 450; and (b) 436nm for the determination of the protonation constants of p-N02Bz(Htpps)P- at 25 "C and an ionic strength of 0.1 mol dm-3 (NaN03). Solid lines are values calculated using -log K,, = 2.51 and -log Ka2 = 7.70 0.6 Q) 5 0.4 e $ 9 0.2 480 0 400 440 Unm Fig.3 Change in absorption spectra (indicated by the arrows) during the reaction of copper(r1) with p-N02Bz(Htpps)4- at pH 7.92, 25 "C and ionicstrength of 0.1 rnol dm-3 (NaN03). [p-NOzB~(Htpps>~-]o = 1.57 x 10-6moldm-3; [CU~~], = 3.11 x 10-6moldm-3. Reaction time: A, 0; B, 3min; C, 1 h; D, 2h; and E, 3h; F denotes the absorption spectrum after heating for 1 minANALYST, NOVEMBER 1991, VOL. 116 1187 period of time (8 h). At pH 5, however, the debenzylation reaction was observed only for copper(i1). The dependence of the rate of debenzylation on the metal ion indicates that cleavage of the C-N bond is the rate-determining step. Those metal ions that form the more stable square-planar metallo- porphyrins produce a faster homolysis reaction. Further, the electron-withdrawing effect of the p-N02 group enhances the C-N bond breaking reaction.Hence, the rapid debenzylation reaction is specific for copper(i1). A large excess of cobalt(i1) or nickel(i1) also caused the debenzylation reaction to occur to a small extent, but the rate was much slower than for copper(ii) because of the slower rate of formation of the metalloporphyrins of p-N02Bz(Htpps)4-. Other N-alkylated porphyrins such as N-methyl- and N-phenylporphyrins did not undergo the homolysis reaction. Effects of Temperature and pH on the Debenzylation of the Copper(11)-pNO~Bz(Htpps)4- Complex Debenzylation of the copper(ii)-p-N02Bz(Htpps)4- complex occurs at room temperature; however, the reaction mixture must be heated for the reaction to go to completion at trace concentrations of copper(1i) (10-7 mol dm-3 level).Heating for 6 min was sufficient for the complete formation of Cu(tpps)4-. The rate of the homolysis reaction was also dependent on pH. As the pyrrole nitrogens of the p-nit- robenzylporphyrin are fully protonated at a pH lower than 3 (pK,, = 2.51), the rate of metallation of the porphyrin becomes slower. Hence, rapid metallation of p-N02Bz- (Htpps)4- was observed at pH values higher than 4, where the p-nitrobenzylporphyrin is mainly in the diprotonated form [N-~-NO~BZ(H~~PPS)'-]. Procedure for the Determination of Copper(r1) After the optimum conditions for the debenzylation of the p-nitrobenzylporphyrin in the presence of copper(i1) had been established, the following procedure was used for the determi- nation of trace amounts of copper(i1).A 5 cm3 water sample containing 0.01-1.3 pg of copper(i1) was placed in a 10 cm3 calibrated flask. Then, lcm3 of acetate buffer (pH 5.0; 0.1 mol dm-3) and 1 cm3 of p-N02Bz(Htpps)4- (2.13 X 10-5moldm-3) were added to the sample solution. The solution was heated in a water-bath at 90°C for 7min and cooled in cold water. Distilled water was added to the mark (10 cm3) and the absorbance was measured at 413 nm against a blank solution of water (Fig. 4). The calibration graph obtained was linear in the range 1-70 ng cm-3 of copper(i1) with a correlation coefficient of 0.999. Levels of copper(i1) of a few nanograms were determined in sample solutions. Effect of Foreign Ions on the Determination of Copper(I1) Metal ions and anions usually encountered in natural water were examined to ascertain whether they interfered with the determination of copper(i1) (305 ng).The tolerance limits for the metal ions studied were: 200 pg for Ag+, Mn2+ and Zn2+; 20 yg for AP+ , Fe2+ and Ni2+ ; and 2 pg for Co2+ , Fe3+ and Pd2+. Sodium tartrate (1 X 10-3 mol dm-3) was added to prevent the hydrolysis of Al3+ and Fe3+ and the interference due to the formation of metalloporphyrins of Co2+ and Ni2+. Excess of zinc(i1) and palladium(ii) did not interfere with the determination of copper(i1). This is a notable feature of the proposed method compared with the determination of cop- per(ii) using the non-N-alkylated porphyrin (H2tpps)4- , where zinc(ii) and palladium(n) interfere with the determina- tion of copper(ii), even at amounts comparable to copper(i1).Further, the following anions (moldm-3) also did not interfere with the determination of copper(i1) using the proposed method: CI- (5.0 x 10-2), Br- (1.0 x lO-3), I- (1.0 x lo-,), SCN- (1.03 x lo-"), S042- (1.03 x lO-3), S2O32- (1.0 x 10-4) and Si03*- (1.0 x 10-4). 0.6 0 2 0.4 ([I e % 9 0.2 n " 400 440 h/nm Fig. 4 Typical absorption spectra after the homolysis reaction of ~1-N0~Bz(Htpps)~- in the presence of co per(1i): [ C U ~ ~ ] ~ : A, 0; B, 1.93 x C, 3.86 x D, 5.78 x lo-?; E, 7.71 x 10-7; F, 9.64 x and G, 11.5 X mol dm-3. pH = 4.96. (The arrows indicate the change in absorbance) Table 1 Determination of copper(i1) and results of recovery experi- ments in natural waters using the proposed method.Sample volume, 5 cm3; pH = 5.06 Sea-water* River water Cu" found yg CU" CU" CU" 0 0.014 0 0.053 0.134 0.045 0.113 0.129 0.098 0.149 0.231 0.141 0.225 0.246 0.195 0.246 0.329 0.239 0.338 0.355 0.293 0.344 0.427 0.337 Average: 0.017 Average: 0.052 0.134 0.044 addedyg addedlyg addedlyg A B C 0.003t 0.OlOt 0.027t 0.009t * An interstitial sea-water from the mud at the bottom of the t Values in yg cm-3. Ariake Sea. Three samples (A, B and C) were analysed. Determination of Copper@) in Natural Waters The proposed method was applied to the determination of copper(i1) in a river water sample and in interstitial sea-water samples from the mud at the bottom of the Ariake Sea. The results are shown in Table 1 together with the recovery of copper(i1) from these natural waters.Nanogram amounts of copper(ii) were determined successfully and the values were checked by atomic absorption spectrometry (AAS); however, AAS gave a large background noise for the determination of ppb levels of copper. Conclusion The N-p-nitrobenzylated porphyrin studied showed the fol- lowing features for the determination of copper(i1): (1) the metallation reaction of the p-nitrobenzylporphyrin was faster compared with the non-benzylated porphyrin (H,tpps4-); (2) the debenzylation reaction was found to depend on the metal ion and the reaction was rapid for copper(x1) as this ion formed a square-planar metalloporphyrin; (3) a large change in the absorption spectra was observed after debenzylation of the1188 ANALYST, NOVEMBER 1991, VOL. 116 metalloporphyrin; and (4) the molar absorptivity was high (4.22 x lo5 dm3 mol-1 cm-1) and the Sandell sensitivity was 0.15 ng cm-2 of copper(I1). The sensitivity of the proposed method is comparable to AAS. In addition, the proposed method is simple, and copper(I1) in natural waters can be determined directly. This work was supported in part by a Grant-in-Aid for Scientific Research (No. 03640498) and a Grant-in-Aid (No. 02245212) on the Priority Area of ‘Molecular Approaches to Non-equilibrium Processes in Solutions’ from the Ministry of Education, Science and Culture, Japan. We also thank the Ito Science Foundation for its support. References 1 Tabata, M., andTanaka, M., TrAC, Trends Anal. Chem. (Pers. Ed.), 1991, 10, 128. 2 Ishii, H . , Bunseki, 1981, 865. 3 Yotsuyanagi, T., Hoshino, H., and Igarashi, S . , Bunseki, 1985, 496. 4 Itoh, J . , Yotsuyanagi, T., and Aomura, K., Anal. Chim. Acta, 1975, 74, 53. 5 Lavallee, D. K., White. A . , Diazy, A . , Battioni, J.-P., and Mansuy, D., Tetrahedron Lett., 1986, 27, 3521. 6 Lavallee, D. K., personal communication. 7 Funahashi, S . , Ito, Y . , Kakito, H., Inamo, M., Hamada, Y . , and Tanaka, M., Mikrochim. Acta, Part I , 1986, 33. 8 Tabata, M., and Tanaka, M., J. Chem. SOC., Chem. Commun., 1985,42. Paper 1102302 K Received May 16th, 1991 Accepted July 19th, 1991

ISSN:0003-2654    

DOI:10.1039/AN9911601185

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYST, NOVEMBER 1991, VOL. 116 1189 Study of Hypersensitive Colour Reactions of Tin(iv) With 2,6,7-Trihydroxyphenylfluorone Derivatives in the Presence of Nitrilotriacetic Acid and Mixed Surfactants Dong-jin Wang, Zeng-hong Xie, Qing-lian Wu, Yu-jun Song and Shun-yu Jin Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, People's Republic of China The hypersensitive colour reactions of tin(1v) with three 2,6,7-trihydroxy-9-phenyI-3-fluorone derivatives, namely 4,5-di bromophenylfluorone (4,5-DBPF), o-hydroxyphenylfluorone and o-nitrophenylfluorone, in the presence of both nitrilotriacetic acid and cetyltrimethylammonium bromide-Tween-80 are described. It is shown that the molar absorptivities of these complexes are 1.42 x 106 (560 nm), 1 .O x 106 (525 nm) and 1.03 x 106 (538 nm) dm3 mol-1 cm-1, respectively, indicating that the proposed technique is the most sensitive spectrophotometric method for the determination of tin(1v) developed so far.The system has been investigated in detail. The tin(1v) complex is formed at pH 2.8-3.9. Beer's law is obeyed for tin(1v) in the range 0.05-0.7 pg per 10 mi. The complex is stable for at least 2.5 h. The molar ratio of tin(1v) to 4,5-DBPF was found to be 1 : 4. Tolerance limits are given for 27 foreign ions by using tartrate, mandelic acid and lactic acid. The method was successfully applied to the determination of trace amounts of tin(iv) in a zinc-base alloy, a lead-copper alloy and alloy steels with low molybdenum contents. Keywords: Tin(1v) determination; spectrophotometry; 2,6,7-trihydroxypheny/f/uorone derivative; mixed surfactants Since cetyltrimethylammonium bromide (CTMAB) was found to increase greatly the sensitivity of the tin(1v)-Pyro- catechol Violet (PV) system, 1 the micellar solubilization spectrophotometric determination of tin(iv) has been de- veloped extensively.2-22 The most widely used acidic dyes are PV,1-4 Gallein,S Pyrogallol Red (PR)6 and Bromopyrogallol Red (BPR).7 These methods have not proved satisfactory with respect to sensitivity (E < 105) and selectivity.The sensitivity of the tin(iv) system is high,g but the selectivity is low, and its application is restricted. The phenylfluorone method, the use of 2,6,7-trihydroxy- phenylfluorone (2,6,7-THPF) derivatives for the determi- nation of tin(iv), has been suggested for the improvement of sensitivity, but the procedure requires that tin(rv) iodide should be extracted into benzene9.10.12 or toluene.2 Recently, the use of THPF derivatives as chromogenic reagents for tin(rv) has been studied.The most extensively used derivatives are 4,5-di bromophen y 1 fluorone( 4,5-DB PF) ,l5,16 0- hydroxy- phenylfluorone(o-HPF) ,17,18 o-nitrophenylfluorone(o- NPF),18 disulphophenylfluorone(DSPF),19 2' ,4'-dichloro- phenylfluorone(DCPF)20 and o-chlorophenylfluorone(o- CPF).21,22 These methods have improved selectivity, but the best value for the molar absorptivity of the complexes is only 2.01 x 105 dm3 mol-1 cm-1.1* It has been shown that 4,5-DBPF is a sensitive reagent for the determination of many metal ions.23-31 This paper describes a system for the determination of tin(1v) with both high sensitivity and selectivity. The reactions of tin(1v) with 4,5-DBPF, o-HPF and o-NPF in the presence of nitrilo- triacetic acid (NTA) and mixed surfactants have been studied.The results show that the method is hypersensitive and the foreign ions which usually interfere with the determination of tin, such as A P , C P , Wvl, Bill1, Vv, Fell1, Nil1 and Z P , can be tolerated in the presence of masking agents. Experimental Apparatus All absorbance measurements were made with a Model 721 spectrophotometer (Xiamen Analytical Instruments, Xiamen, China). A Leichi Model 25 pH meter (Shanghai Leichi Instruments, China) was used for all pH measure- ments. Reagents All chemicals used were of analytical-reagent grade and were obtained from Shanghai Chemical Reagent Factory, China, unless stated otherwise; all solutions were prepared with doubly de-ionized water.Tin(1v) stock solution, 100 pg ml-1. Dissolve metallic tin (purity 99.9%) in HCI (1 + 1) by heating on a water-bath (50-60 "C). Dilute the stock solution with 20% HCl to give a working solution of 1.0 pg ml-1. 4,5-Dibromophenylfluorone, 1.0 X 10-3 mol dm-3. Dis- solve 47.8 mg of 4,5-DBPF (synthesized in this laboratory) in 1 ml of 6 mol dm-3 HC1 and<dilute to 100 ml with absolute ethanol. Store in a brown bottle. Nitrilotriacetic acid solution, 0.20 rnol dm-3. Dissolve NTA (Shanghai First Reagent Factory, China) in 1 mol dm-3 NaOH solution. Cetyltrimethylammonium bromide solution, 5.0 X rnol dm-3. Buffer solution, pH 3.1.Mix 0.02 rnol dm-3 potassium hydrogen phthalate and 0.1 rnol dm-3 HCl. Adjust the solu- tion to pH 3.1 using a pH meter. Polyoxyethylene sorbitan monooleate( Tween-80) solution, Potassium sodium tartrate solution, 20% d v . Ascorbic acid solution, 10% d v . Mandelic acid solution, 2% d v . Obtained from the Beijing Third Chemical Reagent Factory, China. Lactic acid solution ( 1 + 4), v/v. Obtained from the Shanghai Xinhai Lactic Acid Factory, China. 2,4-Dinitrophenol solution, 0.04% d v . 4% V/V. General Procedure Transfer an aliquot of the solution containing less than 0.70 pg of tin(iv) into a 10 ml calibrated flask. Add 1.0 ml of NTA and three drops of 2,4-dinitrophenol solution. Adjust the acidity of the solution with 10% NaOH solution until a yellow colour appears, then add 1 rnol dm-3 HCI dropwise until the yellow colour disappears.Add 2.3 ml of buffer solution (pH 3.1), 1.0 ml of 4,5-DBPF, 1.0 ml of Tween-80 and 0.8 ml of CTMAB solution. Dilute to the mark with water and mix thoroughly. Heat the contents on a water-bath at 45 "C for 12 min, and1190 ANALYST, NOVEMBER 1991, VOL. 116 allow to cool under running water to room temperature. Measure the absorbance at 560 nm in a 0.5 cm cell against a reagent blank. Application Weigh accurately about 500 mg of zinc alloy into a beaker, add 10 ml of HCI (1 + 3) and heat the sample gently until it dissolves. Add 8-10 drops of 30% H202 slowly and expel H202 by boiling the solution for 5-6 min. Cool the solution, transfer it into a 25 ml calibrated flask and dilute to the mark with water.Take 1.0 ml of the solution for the determination of tin, then carry out the Recommended Procedure. Weigh accurately about 500 mg of lead-copper alloy into a beaker, add 10 ml of HN03 (1 + 3) and heat the sample gently until it dissolves. Add 3 mol dm-3 H2S04 until PbS04 and Ag2S04 are precipitated completely. Filter and wash the precipitate, with 1 mol dm-3 HzSO4, into a 25 ml calibrated flask and dilute to the mark with water. Take 1.0ml of the solution and carry out the Recommended Procedure. Weigh accurately 100-500 mg of alloy steel into a beaker, add 25 ml of H2SO4 (1 + 4) and allow to stand for 7-10 min. Add 5 4 ml of 30% H202, simmer the sample until it dissolves and boil it for 8-10 min. Add 30% NaOH solution to the solution until Fe(OH)3 is precipitated completely and add an excess of 5 ml of 30% NaOH.Heat the precipitate on a water-bath at 50-60 "C for 5 min. Transfer the mixture into a 100 ml calibrated flask and dilute to the mark with water. Heat the contents on a water-bath at 50-40 "C for 30 min (or allow to stand overnight). Take 1 .O ml of the clear solution and carry out the Recommended Procedure (substitute ascorbic acid for mandelic acid). Prepare a blank solution in the same way. Recommended Procedure Transfer an aliquot of the sample solution (or standard solution) into a 10 ml calibrated flask. Add 1.0 ml of NTA, 0.5 ml of 20% tartrate solution and 0.2 ml of 2% mandelic acid (or 0.5ml of 10% ascorbic acid for alloy steel). Adjust the acidity of the solution as described under General Procedure.Add 2.3 ml of buffer solution (pH 3.1), 1.0 ml of 4,5-DBPF, 1.0ml of Tween-80, 0.8ml of CTMAB and 0.6ml of lactic acid and proceed as described under General Procedure. Construct a calibration graph in the same way. 0.6 8 8 a CrJ 0.4 0.2 0 500 540 580 620 Wavelengthhm Fig. 1 Absorption spectra of tin(1v) complexes in the presence of NTA, Tween-80 and CTMAB (against a reagent blank). 1, 43- DBPF; 2, o-HPF; and 3, o-NPF. Amount of SnlV, l.Opg, using a 0.5 cm cell Table 1 Comparison of spectral characteristics for the determination of tin(rv) System of PH chromogenic reaction range PV-CTMAB 2.2 PR-CDMBAB* 1.0-1.8 BPR-CPB 0.9-1.9 BPR-CPB-Tween-80 2.62-2.94 Phenylfluorone- CTMAB 0.35-O.907 4,5-DBPF-CPB 1.2-1.37 0-HPF-CTMAB 0.25-1.75t U-NPF-CTM AB 0.075-1.257 DSPF-CPC 2-3 DCPF-CTMAB 0.6-2.lt U-CPF-CTMAB 1.0-1.57 NTA-0-NPF-CTMAB- Tween-80 2.5-3.4 NTA-o-HPF-CTMAB- NTA-4,5-DBPF- Tween-80 2.8-3.7 CTMAB-Tween-80 2.8-3.9 hlnaJ nm 662 480 550 530 510 540 510 512 540 5 14 510 538 525 560 * Cetyldimethylbenzylammonium bromide.t Sulphuric acid, 1 mol dm-3. Molar absorptivity/ 105 dm3 mol- cm- Reference 0.95 1 0.65 6 0.30 7 3.72 8 1.19 1.51 1.79 2.01 0.40 1.5 1.92 10.3 11.0 14.2 12 15 17,18 18 19 20 21 This paper This paper This paper Results and Discussion Absorption Spectra A comparison was made of the colour reactions of tin(1v) with three derivatives of 2,6,7-THPF, viz., 4,5-DBPF, o-HPF and o-NPF in the presence of NTA and mixed surfactants. The results show that the molar absorptivities of the complexes are of the order of 106 dm3 mol-1 cm-1.The 4,5-DBPF system is the most sensitive of the three systems (as shown in Fig. 1 and Table 1). Hence the 4,5-DBPF system was studied in detail. The absorption spectra of tin(rv) complexes are shown in Fig. 2. When NTA solution is not added (curve 2), the complex is insoluble (it is necessary to dissolve the complex by adding 1.5 ml of ethanol). In the absence of Tween-80 and the presence of NTA (curve 3), the complex is also insoluble (it is required that the complex be dissolved by using 2.5 ml of ethanol) and the absorbance of the complex is low. In the presence of both NTA and CTMAB-Tween40 (curve l), the complex can be dissolved and the absorbance of the complex (A,,, = 560 nm) is significantly increased.Hence the Tween- 80 acts as both a solubilizing and sensitizing agent for the complex. It is possible that hydrolysis and polymerization of tin(1v) do not occur when using NTA, because of the order of addition of tin(iv), NTA and NaOH solution as a neutralizing agent. It is probable that the NTA and tin(1v) form an intermediate compound first. Conversely, in the absence of NTA, it is possible to hydrolyse and polymerize tin(1v) on neutralizing the tin(1v) directly with NaOH solution. There- fore, the sensitivity and solubility of the tin(1v) complex in the presence of NTA (curve 1) are better than in the absence of NTA (curve 2). Effect of pH A comparative study was made of the effect of three buffer solutions on the sensitivity of the complex. The order of the buffer solutions giving the best sensitivities was potassium hydrogen phthalate-HC1, acetic acid-sodium acetate and urotropine-HCl, and therefore the first named buffer solution was selected.The results show that the maximum absorbances are obtained in the pH range 2.7-3.9 and, therefore, a buffer solution of pH 3.1 was used in all subsequent experiments. Effect of Temperature and Stability of the Complex A constant maximum absorbance was obtained when the solution was heated on a water-bath at 42-48 "C for 10 min and at 45 "C for 1&15 min. A further study was carried out by heating the reactants at 45 "C for 12 min, with the maximum absorbance of the complex remaining constant for 2.5 h.ANALYST, NOVEMBER 1991, VOL. 116 1191 1 0.4 P) s 0.2 e 8 n a 0 -o.2 t V' I I 1 I 1 1 500 540 580 620 Wavelengthhm Fig.2 Absorption spectra of tin(rv) complexes (against a reagent blank). 1, Sn-NTA4,5-DBPF-CTMAB-Tween-80; 2, Sn-4,5- DBPF-CTMAB-Tween-80 (system containing 15% ethanol); and 3, Sn-NTA-4,5-DBPF-CTMAB (system containing 25% ethanol). Amount of SniV, 0.8 pg, using a 0.5 cm cell Effect of the NTA and 4,5-DBPF Concentrations The effect of the NTA and tartrate concentrations on the absorbance of complexes was examined, and the results show that the sensitivity of the NTA system is higher than that of the tartrate system. When 0.4-1.4 ml of 0.20 rnol dm-3 NTA and 0.8-1.2 ml of 1.0 X 10-3 rnol dm-3 4,5-DBPF solutions were added, the maximum absorbances were obtained. Therefore, 1.0 ml volumes of each reagent were subsequently used.Effect of Mixed Surfactants The effect of mixed surfactants on colour reactions have been studied previously.24-36 The use of mixed surfactants gave better analytical characteristics than single surfactants for solubilized reactants, viz., synergistic sensitizing effect [e.g. , Pt"4,S-DBPF complex, CTMAB, E = 5.58 X 105; CTMAB- octyl phenyl polyglycol ether (OP), E = 8.32 x 105];24-27,3@36 solubilizing and stabilizing effect (e.g., in the presence of CTMAB and CTMAB-Triton X-100, the FeIII-4,5-DBPF complex is insoluble and soluble, respectively, and stable for 25 min and for 4 h, respectively);28-35 and broadening of the optimum acidity interval in colour reactions (e.g., Wv14,5- DBPF complex; CTMAB, 1.7-2.2 rnol dm-3 HCI and CTMAB-OP, 2.0-2.8 mol dm-3 HC1).25?29-35 These phe- nomena are universal.31-36 It might be deduced that the microenvironment of mixed micelles in mixed surfactants is different from that of a single surfactant and the changes observed in analytical parameters primarily result from the formation of their mixed micelles.It is possible that the mixed micelles form a proper, close and orderly arrangement in space.34~35 In other words, the formation of mixed micelles of the mixed surfactants plays an important role in the synergism of colour reactions. Hence, as can be seen from Fig. 2, the sensitivity and solubility of the tin(1v) complex in the presence of CTMAB and Tween-80 (curve 1) are better than those in the absence of Tween-80 (curve 3). Fig. 3 shows the effect on sensitivity of various cationic surfactant systems, with a fixed 1 .O ml volume of non-ionic surfactant Tween-80, [CTMAB > cetylpyridi- nium bromide (CPB) > cetylpyridinium chloride (CPC)] and of various non-ionic surfactant systems, with a fixed 0.8 ml volume of CTMAB (Tween-80 > Tween-60 > Triton X-100).Therefore, 0.8 ml of 5.0 X 10-2 rnol dm-3 CTMAB and 1.0 ml of 4% Tween-80 were used. Composition of the Complex The tin(1v) to ligand ratio in the complex was studied by both Job's continuous variations method37 and the molar ratio 0, s 0.3 - e n u. 0.2 . 0.1 I I I 1 0 0.4 0.8 1.2 1.6 Vol u me/m I Fig. 3 Effect of various surfactants (5.0 X 10-2 rnol dm-3) on absorbance. 1, CTMAB; 2, CPC; and 3, CPB with 1.0ml of Tween-80. Amount of SniV, 0.6 pg Table 2 Tolerable limits of foreign ions in the presence of tartrate, mandelic acid and lactic acid [tin(rv) taken, 0.60 pg] Tolerance ratio, Tolerance ratio, Ion added (ion : SnIv) Ion added (ion : Snlv) 1667 lo00 916 833 667 417 333 250 167 83 83 ZriV Fell1 Sb"', TaV MoV1 A P , Agl Nb" ~ 0 ~ 3 - N03- HC03- so42- * 0.5 ml of 10% ascorbic acid solution was added.67 17 250* 17 8 5 4 4.17 X 103 1.33 x 103 1.67 x 103 667 method.38 The results show that the molar ratio of tin(1v) to 4,5-DBPF is 1 : 4. Beer's Law and Sensitivity Beer's Law is obeyed for tin(rv) in the range of 0.05-0.70 pg per 10 ml (1 cm cell) with a calibration graph represented by A = 0.581~ + 0.011 where A is the absorbance at 560 nm and cis the concentration of tin(1v) (pg per 10 ml). The correlation coefficient is 0.9988 and the molar absorptivity of the complex is 1.42 X 106 dm3 mol-1 cm-1.So far the proposed method has proved to be the most sensitive of all the spectrophotometric methods for the determination of tin(1v). Precision and Accuracy Under optimum conditions, for the addition of 0.50pg of tin(iv), the mean recovery is 101%. The standard deviation (SD) and relative standard deviation (RSD), calculated from eight replicate analyses, are 0.013 pg and 3.1%, respectively. The method was applied successfully to the determination of tin in zinc alloy, lead-copper alloy and alloy steel. Table3 shows that the values obtained by the proposed method are in reasonable agreement with certified values. The precision and accuracy are satisfactory. Interferences The effects of some masking agents on absorbance were examined.The results show that the absorbances are not reduced when a fixed amount of tartrate, mandelic acid and ascorbic acid are added before the formation of the tin complex, and lactic acid is added after the formation of the tin complex. In the presence of masking agents, the tolerable1192 ANALYST, NOVEMBER 1991, VOL. 116 Table 3 Comparison of results for the determination of tin. All values in % Certified Proposed 95% confidence Sample type value method SD level RSD (%) Zinc-base alloy (Benxi Alloy Factory) 0.0032 0.0032 0.00010 0.0033 f 0.0001 3.0 0.0032 0.0034 0.0032 0.0032 0.0026 0.0025 0.0026 0.0027 0.034 0.035 0.034 0.033 0.0073 0.0068 0.0071 0.0068 0.048 0.054 0.050 0.047 Pb-Cu alloy (Beijing Steel Institute) 0.0029 0.0026 O.ooOo7 0.0026 f 0.0001 2.7 Alloy steel (Shanghai Materials Institute) 0.035 0.034 0.00099 0.034 k 0.001 2.9 Alloy steel (Shanghai Materials Institute) 0.0074 0.0072 0.00024 0.0070 k 0.0003 3.4 Alloy steel (W3CrV) (Beijing Steel Institute) 0.050* 0.050 0.0028 0.049 f 0.003 5.7 *100 yg of TilV and 0.5 pg of SnIv were added (tin content added to the sample corresponds to 0.050%).limit of foreign ion is taken as a relative error not greater than &5% in the recovery [0.6 pg of tin(1v) per 10 ml]. The results are given in Table 2. The tolerance of Zn" is very large, hence the method can be applied directly to the determination of tin in zinc alloy, but TiIV and GelV cause serious interference. Fortunately, when NaOH solution is added to the sample solution, as tin is an amphoteric element, Ti1", FelI1, Coil and ions form precipitates in the form of hydroxides, in solutions where A102-, Pb022-, VO3-, Cr02- and W042- coexist with SnIV (their tolerances are large); Mo can be present in an 8-fold excess.Hence the method can be applied to the determination of tin in alloy steels containing low amounts of Mo without extraction of tin(1v) iodide into benzene or tol~ene.2~9JOJ2~14 This paper describes a method that can be used for the determination of tin in water, cans and minerals melted with Na202. Conclusion A detailed study has been made of the colour reaction of tin(1v) with 4,s-DBPF in the presence of NTA and CTMAB- Tween-80 and its application. The main advantages of the proposed method are hypersensitivity, simplicity in operation and rapidity of results without extraction of tin(1v) iodide into benzene or toluene.The results of the analysis of practical samples show that the precision and accuracy are satisfactory. References Dagnall, R. M., West, T. S., and Young, P., Analyst, 1967,92, 27. Ashton, A., Fogg, A. G., and Burns, D. T., Fresenius 2. Anal. Chem., 1973,264, 133. Ashton, A., Fogg, A. G., and Burns, D. T., Analyst, 1973,98, 202. 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Ding, J.-c., Fenxi Huaxue, 1978, 6 , 242. Mori, I., Bunseki Kagaku, 1970, 19,455. Wyganowski, C., Mikrochirn. Acta, Part I , 1979,399. Tran, H. C., Nemcova, I., Nemec, I., and Suk, V., Anal. Chim. Acta, 1980, 115,279. Xu, Y.-x., Zhao, Y.-p., and Ci, Y.-x., Fenxi Huaxue, 1987,15, 1028.Luke, C. L., Anal. Chim. Acta, 1967, 39,404. Agterdenbos, J., and Vlogtman, J., Talanta, 1972, 19, 1295. Yamazaki, M., Mori, I., and Enoki, T., Bunseki Kagaku, 1973, 22,112. Zhang, D.-l., Xu, H.-p., and Lin, X.-t., Fenxi Huaxue, 1976,4, 218. Kulkarni, V. H., and Good, M. L., Anal. Chem., 1978,50,973. Asmus, E., and Weinert, H., Fresenius 2. Anal. Chem., 1970, 249, 179. Antonovich, V. P., Suvorova, E. N., and Shelikhina, E. I., Zh. Anal. Khim., 1982,37,429. Liu, J.-c., and Liu, J.-p., Fenxi Huaxue, 1984, 12, 143. Xu, G.-h., and Shen, H.-x., Fenxi Huaxue, 1982, 10,334. Shen, H.-x., and Wang, L.-s., Huaxue Shiji, 1983, 5 , 262. Nazarenko, A. Yu., Zh. Anal. Khim., 1988,43,269. Ye, N.-x., Xi, G.-q.. and Liang, D.-z., Yejin Fenxi, 1987,7,26.Liu, R.-p., Gao, S., and Qin, G.-r., Fenxi Huaxue, 1989, 17, 602. Chen, T.-s., and Hug, Y., Yejin Fenxi, 1988, 8, 18. Pan, Q.-h., Wang, D.-j., Cai, Z.-g., He, W.-j., Xiao, Z.-j., Wu, P.-r., and Huang, Y.-x., Huaxue Shiji, 1985, 7,321. Wang, D,-j., Shi, S.-w., Fu, Y.-c., and Pan, Q.-h., Huaxue Shiji, 1983, 5 , 337: Chem. Abstr., 1984, 100,95705d. Wang, D.-j., Chen, J.-h., Bai, J.-y., and Pan, Q.-h., Huaxue Shiji, 1984, 6 , 139; Chem. Abstr., 1984, 101, 182949a. Wang, D.-j., Chen, J.-h., Bai, J.-y., and Pan, Q.-h., Gaodeng Xuexiao Huaxue Xuebao, 1983,4,809; Chem. Abstr., 1984,100, 61036~. Wang, D.-j., Zhuang, J.-y., Zhuang, Y.-p., Tian, S.-j., and Pan, Q.-h., Fenxi Huaxue, 1990, 18,766. Wang, D.-j., Liao, W.-p., Huang, X.-d., and Pan, Q.-h., Fenxi Huaxue, 1987, 15, 689; Chem. Abstr., 1988,108, 123613h. Zhuang, J.-y., Wang, D.-j., Shu, H., and Pan, Q.-h., Fenxi Huaxue, 1987, 15, 874; Chem. Abstr., 1988, 108, 123621j.ANALYST, NOVEMBER 1991, VOL. 116 30 Wang, D.-j., Xie, G.-z., Zhang, W.-c., and Pan, Q.-h. , Huaxue Shiji, 1985, 7 , 33. 31 Wang, D.-j., Chen, T.-m., Xie, Z.-h., Tian, S.-j., and Pan, Q.-h., Acfa Chim. Sin., 1991, 49,70. 32 Zhang, G.-z., and Shi, H.-m., Huuxue Shiji, 1987, 9, 85. 33 Qi, W.-b., and Zhu, L.-z., Bull. Anal. Test., 1986, 5 , 1. 34 Zeng, Y.-x., Rock Miner. Anal., 1986,5, 169 and 253. 35 Zeng, Y.-x., Rock Miner. Anal. , 1987,6, 1. 36 Qi, W.-b., and Zhu, L.-z., Gaodeng Xuexiao Huaxue Xuebao, 1986, 7,406. 1193 37 Job, P., Ann. Chim., 1928, 9, 113. 38 Yoe, J. H., and Jones, A. L., Znd. Eng. Chem. (Anal. Ed.), 1944, 16, 111. Paper 1100044F Received January 3rd, 1991 Accepted July 8th, 1991

ISSN:0003-2654    

DOI:10.1039/AN9911601189

出版商:RSC    

年代:1991

数据来源: RSC

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ANALYST, NOVEMBER 1991, VOL. 116 1195 Rapid and Selective High-performance Liquid Chromatographic Method for the Determination of Michler‘s Ketone in Methyl Violet 2B Sava R. Lukac ASTBLrippen Laboratories Inc., 4027 New Castle Avenue, New Castle, DE 19720, USA A high-performance liquid chromatographic method for the determination of ppm levels of Michler’s ketone (MK) in Methyl Violet 2B (MV) is described. The direct determination of MK in a methanolic solution of MV is made possible by the presence of a spectral window between 300 and 400 nm in the spectrum of MV. This simple isocratic high-performance liquid chromatographic method gave a limit of detection for MK of 1 ppm. Keywords: Michler‘s ketone; isocratic high-performance liquid chromatography; ultraviolet detection Michler’s ketone [4,4’-bis(dimethylamino)benzophenone] (MK) is frequently present as an ‘impurity’ in triphenyl- methane dyestuffs or it can be found as a major photodegra- dation product in other types of dyes.’ For screening purposes, a rapid and simple analytical procedure to deter- mine low levels (ppm range) of MK is needed.The usual extraction methods used are not convenient for Methyl Violet 2B (MV), as there is no marked difference in the solubilities of these two compounds in any common solvent. A direct sampling of the original sample under reversed-phase isocratic 300 400 500 600 700 Wavelengthlnm Fig. 1 Spectrum of A, MK superimposed on the spectrum of B, MV (approximate concentrations, 1 X 10-4 and 8 x 10-5 mol dm-3, respectively) 3.81 9.14 I Time/min Fig.2 Chromatogram of MV recorded at 350 nm. Peak A corresponds to MK (45 ppm) in the presence of a 200-fold excess of the dye (detector attenuation, 1; integrator attenuation, 3) conditions, even with a high content of organic phase, leads to masking of the peak of MK by the broad peak of MV. In this paper, advantage was taken of a spectral window in the spectrum of MV to develop a simple method for the detection of small amounts of MK in MV. Experimental A sample of crystalline MV was dissolved in methanol. The highest possible concentration of MV that passed through a 0.45 pm syringe filter was about 1%. This solution was directly injected using a 20 yl loop onto a 250 x 4.6 mm i.d. 5 pm ODS VAL-U-PAK HP column (Regis Chemical Co., Morton Groe, IL, USA).The mobile phase used was 30% water in methanol with a flow rate of 1 ml min-1. The eluted compounds were detected by a variable-wavelength ultra- violet/visible (UVNIS) detector set at 350 nm. The MK (Aldrich) standard solutions were prepared in methanol. The signal from the detector was fed to a recording integrator and the areas of the peaks were used for the quantitative analysis. Results The UVNIS spectra of MV and MK presented in Fig. 1 show that it is possible to use the spectral window between 300 and 400 nm for the detection of MK in the presence of a large amount of MV. This approach allowed MV to be screened rapidly for the presence of MK down to the pprn level without any sample preparation procedure. A typical chromatogram of the analysis of MV for the presence of MK is shown in Fig. 2. This chromatogram shows the results obtained for a 200-fold excess of the dye over MK. When a higher dilution of MV is permitted (below 0.5%), the large tailing peak of MV completely disappears at this wavelength. A linear regression of the analysis of the standard solutions performed under the described conditions resulted in a correlation coefficient of 0.999 for concentrations of MK between 1 and 20 ppm. The limit of detection for MK at a dye concentration of 1%, determined by spiking the methanolic dye solution, was found to be 1 ppm. The author thanks G. Segal for technical assistance. Reference 1 Voyksner, R. D., Pack, T. W., Haney, C. A., Freeman, H. S . , and Hsu, W.-N., Biomed. Environ. Mass Spectrom., 1989, 18, 1079. Paper 1 I01 520F Received March 25th, 1991 Accepted July 3rd, 1991

ISSN:0003-2654    

DOI:10.1039/AN9911601195

出版商:RSC    

年代:1991

数据来源: RSC

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ANALYST, NOVEMBER 1991, VOL. 116 1197 BOOK REVIEWS Milk. Ongoing Activities and Future Prospects. Annali dell’lnstituto Superiore di Sanita Edited by S. Caroli, E. Coni and E. Sabbioni. Ann. 1st. Super. Sanita, 7990, vol. 26(2), pp. 707-775. lstituto Superiore di Sanita. Price $20.00: Lit22 000. ISSN 0021- 2571. This slim volume of a Journal contains seven papers describing the analytical work, on both human and cows’ milk collected in Italy, carried out up to about mid-1989 by various research groups within the Institute. Some of the research groups are currently collaborating with other groups outside Italy through international organizations, such as the World Health Organization. The papers contain summaries of comparable data produced by other countries. This puts the Italian data into perspective, enabling world-wide trends to be indicated and widens the value of the publication.The analytical topics covered in this publication are the measurement of levels of radioactivity (following the Cher- nobyl incident), selected metals, total protein and individual amino acids, total lipid and individual fatty acids, poly- chlorobiphenyls (PCBs), polychlorodibenzodioxins (PCDDs) , polychlorodibenzofurans (PCDFs) , p p’-DDE, p,p’-DDT and some antimastitis drugs. Data have been obtained from adequately sized groups of samples for the various topics. The analytical techniques employed are generally those recommended internationally so that the references are a useful source of this type of information. The general conclusion that can be made from the papers is that human milk continues to be safe for infant feeding, but that in some instances the margin of safety is not high and that further monitoring, on a world-wide scale, is required.From an analytical point of view it is very useful to bring together in one publication different topics on milk, because the danger of becoming a specialist in one particular topic is that the significance of other aspects of this complex natural product can easily be overlooked. For those working on the analytical aspects of milk, this is a useful publication at a reasonable cost. Similar publications for other countries, including the UK, would be welcome. Terry M . Jefferies Principles and Practice of Analytical Chemistry. 3rd Edition By F. W. Fifield and D.Kealey. Pp. xii + 521. Blackie. 1990. Price f 19.95. ISBN 0-216-92920-2. This is the third edition of one of the early student textbooks for the teaching of modern analytical chemistry at college and early university level. It follows the now conventional combination of classical and instrumental methods and for most modern courses the techniques covered are well selec- ted. As would be expected, it is largely biased towards instrumental techniques, but includes chapters on pH, com- plexation, solubility equilibria and titrimetry. Taking as an example the chapter on separation techniques, a whole variety of forms of chromatography are considered together. Whilst this unifies some of the theory, it does so at the expense of clarity. High-performance liquid chromato- graphy (HPLC), section 4.2.2., includes ion chromatography.Within this section, subsection 1 (not 4.2.2.1.) is ‘Solvent Delivery Systems’. After HPLC are 4.2.3. ‘Supercritical Fluid Chromatography,, 4.2.4. ‘Thin-layer Chromatography’ and only then 4.2.5. ‘Ion-Exchange Chromatography,. This chapter in particular suffers from poor sequencing of material, a very confusing choice of section numbering and an inade- quate use of fonts and type sizes to distinguish levels clearly. Attempts to explain the optimization of a separation by overlapping resolution maps, ion chromatography and super- critical fluid chromatography have not been successful and as elsewhere, an attempt to mention all the techniques has been the downfall. I have always had reservations about the formatting and presentation of this book and the latest edition is no exception.Illustrations have changed a lot since the book was first produced, and there is now a very distinct difference between the recent figures and those originating from the first edition. In places it is difficult to read the figure labelling and legends owing to the small character size and poor reproduc- tion. Fig. 8.1, the sodium energy level diagram, has no units for the energy axis and specifies the units incorrectly on the transitions. These errors were present in the first edition. The book presentation now appears dated and I fear that it might also be rather too wordy for some modern readers. For those requiring a gentler alternative to the terse notes obtained from lectures and some books, however, this book might still be a fairly good option.Alan G. Howard An Introduction to Laboratory Automation By Victor Cerda and Guillermo Ramis. Volume 770 in Chemical Analysis: A Series of Monographs on Analytical Chemistry and its Applications. Pp. xiv + 321. Wiley- Interscience. 1990. Price f 55.1 5. ISBN 0-471 -61 81 8-7. This is, in some ways, a curious book. It is clearly written by two chemists who, in their own words, have learnt about the subjects described through a ‘self-educational’ process. However, it contains little of what many would class as automatic chemistry: sample manipulation, reagent mixing, hydraulics, etc. Instead it focuses five out of the nine chapters (207 pp. out of 304) on basic analogue, digital and computer electronics.Of the remaining chapters, Chapter 1 is a very brief (6 pp.) introduction to the stages in automating laboratory processes, Chapters 7 and 9 deal with specific types of laboratory instrumentation and robotics, and Chapter 8 describes six applications from the authors’ laboratories. The chapters on analogue and digital electronics are fairly comprehensive in scope but necessarily limited in detail. A complete beginner would readily appreciate the principles involved with the various devices, but my own self-educational process in this area suggests that reference to good practical electronics texts would be needed before working circuits could be constructed. Similarly with the chapter on micro- processor design and coding. The principles of design and coding will be useful but it is limited to the chosen processor, the Intel 8085.The chapter on communications, however, is timeless and really useful in describing the main serial and parallel communications protocols and how they are programmed in high level languages. Anybody who is mystified by RS232 or lEEE 488 will find this chapter an excellent starting point. The descriptions of instrumentation and robotics have to be selective for reasons of space. The chapter on robotics is very brief, only 15 pp., with 10 of these taken up with the principles of motors and position sensors. Robots as such, are squeezed into the last 5 pp., almost as an afterthought. In comparison, the chapter on instrumentation will be valuable to those wishing to use off-the-shelf instruments in an automation system.Again the focus is on the communications between the instruments and the computer, but the descriptions of status and control systems, together with fragments of programs, establish the principles for using any instrumentation in this way.1198 ANALYST, NOVEMBER 1991, VOL. 116 The six applications described in Chapter 8 demonstrate clearly what can be achieved in automation. Unfortunately, there is little attention given to the systems level control and design, which ensures that the mix of electronics, mechanics and hydraulics actually works reliably. A final curiosity of the book is the bibliography; about half of the non-specific instrument references are to Spanish language texts. This book will provide a good introduction to the principles of electronics, interfacing and communication with instruments to someone unfamiliar with the subjects; it does not provide practical advice on how to make complete systems work reliably.Anyone contemplating incorporating one of the named instruments in a system will find Chapter 7 a useful complement to the instrument manufacturer’s manuals, but f55 may be too high a price for this. R. L. Tranter Chromatographic Analysis of Alkaloids By Milan Popl, Jan Fahnrich and Vlastimil Tatar. Chromat- ographic Science Series. Volume 53. Pp. viii + 667. Marcel Dekker. 1990. Price $150.00 (US and Canada); $180.00 (all other countries). ISBN 0-8247-8140-6. This book essentially covers the same topic as the extensive reviews by Verpoorte and Baerheim-Svendsen .1,2 In the preface to this new book the authors state their intentions of surveying the more recent literature, discussing particular criteria in the choice and application of published methods to a given problem, and assisting with the analysis of, as yet, unresolved alkaloid mixtures.Chapter 1 provides basic information on alkaloid classifica- tion, nomenclature, chemical structure and occurrence. Chapter 2 discusses the physico-chemical properties of alka- loids relevant to chromatography, particularly to LC, which is the dominant method of their chromatographic analysis. The dissociation properties of alkaloids are discussed, not only in aqueous solution but very commendably, also when organic solvent-water mixtures are employed as in reversed-phase LC separations.This is a topic to which few chromatographers, unfortunately, give much thought. Included is a discussion of UVNIS absorption and electrochemical properties of com- mon alkaloids. These methods of detection, along with the addition of fluorescence and refractive index detection are returned to in Chapter 5. One questions why this division was necessary; some contradictions also seemed to result between the two electrochemistry sections. However, useful tables of data have been collected by the authors from diverse sources. Chapter 3 contains a brief summary of chromatographic theory with a generalized description of a column chromato- graph (for GC or LC). Chapter 4 begins with an outline of the particular intrumentation and techniques utilized in GC.Although these sections are of necessity fairly brief, some readers will be frustrated by the lack of references to guide them in further reading. Chapter 4 concludes with a review of about 100 references of GC analyses, the most recent being from 1986. Chapter 5, Liquid Chromatography, gives an excellent and very useful description of the separation mechanisms used in LC. Not only are the basic mechanisms covered but also, as the authors promised in the preface, particular problems and techniques relevant to alkaloid analysis are fully discussed. The chapter deals essentially with HPLC, although the authors make limited use of this name and there is little discussion of column particle size effects. About 500 applica- tions of column LC to alkaloid analysis are discussed with the most recent being from 1986-87.Apart from the section on (column) LC detectors mentioned above, and the generalized remarks in Chapter 3, there is no systematic description of the instrumentation for HPLC. Some readers might have appre- ciated an outline summary or recommendations for further reading. The format of Chapter 6 on thin-layer chromatography is more similar to the GC chapter, with a brief description of apparatus, separation mechanisms and a discussion of applica- tions including about 200 references, the most recent again being from 1986 to 1987. Chapter 7 contains details of sample preparation pro- cedures and extraction techniques, but is dominated by an extensive tabulated summary of the GC, column LC and TLC analysis conditions for a wide variety of alkaloids taken from about 500 references.The format of this chapter has allowed references from up to 1988 to be included. The chapter concludes with a dicussion of the separation of the alkaloids, class by class, using the three chromatographic methods. This has allowed comparisons of relative method suitability to be made although there is some repetition of material from previous chapters. Chapter 8 is a brief conclusion of this technique comparability theme. A number of illustrative chromatograms from the literature are included. Some of these are fairly crudely re-drawn from the original diagrams with the consequence that information on peak shape is lost. This is a pity considering the importance of the data for these compounds, the properties of which often make them difficult to analyse.The reviews of both TLC and GC are much less extensive than those produced by the previous authors although this probably reflects the domi- nance of the use of HPLC for alkaloid separations over the last 10 years. Despite the rather high price of this book and the publication lag that has led to the exclusion of very recent material, it will appeal to workers in the field, particularly for its coverage of column LC separations not available in the earlier reviews. D. V. McCalley References 1 Verpoorte, R., and Baerheim-Svendsen, A., Chromatography of Alkaloids, Journal of Chromatography Library, Elsevier, Amsterdam, 1983. 2 Verpoorte, R., and Baerheim-Svendsen, A., Chromatography of Alkaloids, Journal of Chromatography Library, Elsevier, Amsterdam, 1984.Electroanalysis of Biologically Important Compounds By J. P. Hart. Ellis Horwood Series in Analytical Chem- istry. Pp. 213. Ellis Horwood. 1990. Price f42.50. ISBN 0-1 3-2521 07-5. This short book draws the analyst’s attention to the many electroanalytical techniques now available for the trace determination of biologically significant molecules. An intro- ductory chapter on electroanalytical methods is followed by a chapter on each of four important classes of these compounds. The first chapter on electroanalytical methods contains basic but essential information on voltammetry and polaro- graphy. A concise guide to the different types of methods including pulse, square wave, linear sweep and cyclic voltam- metry is followed by an introduction to stripping voltammetry.Experimental considerations are briefly and rather uncritically dealt with, and the chapter concludes with a look at electrochemical detection for both liquid chromatography (LCEC) and flow injection analysis. The value of this narrow account of a broad subject is perhaps debatable. It was rather surprising that in a book devoted to what are often ultra-trace determinations, stripping voltammetry merits a mere page. However, the author does reference several more extensive treatments. As electroanalysis is still regarded as something ofANALYST, NOVEMBER 1991, VOL. 116 1199 a ‘black art’ by many, the value of this introductory chapter might be that the subject is introduced in a comparatively painless, logical and non-overwhelming manner. The electroanalysis of purine and pyrimidine bases com- prises Chapter 2. Like the succeeding chapters it is written in the style of a review article. There is an almost total lack of critical comment throughout the book as to the value of the methods that are quoted as examples.Again, in common with the succeeding chapters, classification of the examples quoted is in terms of the electroanalytical methods employed. The analysis of amino acids, peptides and proteins is covered in Chapter 3. Here, attention is drawn to the significance of the highly sensitive stripping techniques for the determination of cysteine-related compounds such as the penicillins, and to LCEC procedures, including such well- known pre-column derivatizations as that with phthalaldehyde and mercaptoethanol. Chapter 4 covers vitamin analysis; both water and fat- soluble vitamins are considered.A useful summary table is given for the electroanalysis of the various B vitamins, and this sort of compilation could have been used to much greater effect throughout the book. In common with other chapters the references are not as up to date as would have been desirable. Finally, a brief chapter is devoted to the electroanalysis of selected coenzymes. Nicotinamide adenine dinucleotides are dealt with in some detail, with the analysis of other nucleotides with coenzyme functions restricted to a summary table. The chapter also covers the important coenzyme groups, pterins, ubiquinones and ubiquinols. Emphasis in this chapter is rightly placed on the LCEC methods.Overall, reading this book is like reading a menu comprised only of hors d’ouvres, with the main courses missing. Nevertheless, the author has provided a useful quick reference on electroanalytical methods for numerous biologically im- portant compounds, which are indexed at the end of the text. For this reason the book certainly deserves a place on the library shelf. A . D. Woolfson Flow Injection Analysis. A Practical Guide 60 Karlberg and Gil E. Pacey. Techniques and Instrumen- tation in Analytical Chemistry 70. Pp xii + 372. Elsevier. 1989. Price $1 17.00; Df1240.00. ISBN 0-444-88014-3. This book has grown out of the training courses run by the authors and, as such, borrows somewhat from the literature produced by the company employing the first named author.It is true that there is more in this text than can be obtained from the various Tecator bibliographies and the little booklet ‘An Introduction to the Use of Flow Injection Analysis,’ but possessors of this set of literature would perhaps be expecting more from the additional material promised in a text with this title. As the authors themselves point out, the text is intended as a practical guide and this approach is adopted immediately. The factors controlling the value of the dispersion coefficient at the peak maximum are introduced via the results of experiments in which these factors are varied, albeit between rather restricted upper and lower bounds. Readers who baulk at pages of equations describing diffusion-correction processes and secondary-flow patterns will be relieved to find only qualitative explanations of the dispersion process.It was something of a disappointment, though, not to see a more realistic picture of the effects of dispersion under the conditions of laminar flow in a pipe. The notion of the compact, hollow closed circular bullet bolus is perpetuated. The chapter devoted to ‘Components of FIA’ is good. There is much useful information of a practical nature here which is not available elsewhere, and this chapter, together with the chapter on ‘Developing a Flow Injection Procedure,’ should prove useful to newcomers to the methodology. Between these two chapters, information on ‘Detectors in FIA’ and ‘Sensitivity Enhancement, Matrix Modification and Conver- sion Techniques’ is provided.The second of these chapters illustrates the versatility of flow injection and is only open to the criticism that, at 21 pages, it is too short. There is an even shorter chapter (14 pages) on ‘Utilization of the Concentra- tion Gradient’ which is probably the right length for this topic for a book of this sort. After the chapter detailing the development of a spectrophotometric method for the determi- nation of iron, are three applications chapters covering: ( i ) ‘Water, Agriculture, Soil and Environment’; (ii) ‘Pharmaceut- ical, Clinical and Biotechnology’; and (iii) ‘Food and Feed’. These chapters contain methods for 9 , 7 and 6 determinands, respectively, in a variety of matrices. A final, rather thinly referenced, chapter deals with possible applications of flow- injection procedures in ‘Process and Quality Control’.The remaining 120 pages are taken up with the bibliography. A total of 1392 references (1975-1988) have been included. Papers in languages other than English have been excluded, as have theses, reports, and uncommon and less accessible journals. There are extensive subject indices, but no author index. The authors adopt an easy, relaxed style based on a ‘question and answer’ format and the text is illustrated with a large number of diagrams. While these are clear, they appear to have been produced by a rather primitive drawing program. It’s no big deal and does nothing really to detract from the tutorial flavour of this book. As it costs somewhat less than a basic rotary injection valve, there is no reason why labora- tories in which flow-injection experiments are performed should not have a copy.Julian Tyson Thin-Layer Chromatography. Reagents and Detection Methods, Physical and Chemical Detection Methods. Fundamentals, Reagents 1. Volume 1A Hallmut Jork, Werner Funk, Walter Fisher and Hans Wimmer. Pp. xv + 464. VCH Verlagsgesellschaft. 1990. Price DM148.00. ISBN 3 527 27834 6 (VCH Verlags- gesellschaft); 0 89573 876 7 (VCH Publishers). This book is divided into two parts. Firstly, there is an extensive section dealing with physical methods of detection, which varies from detection with iodine to the detection of radioisotopes. The description of the various techniques is fairly detailed for most subjects. However, the section covering radio-detection is fairly brief, probably because another volume is to be published on this subject in the future.Part 1 also includes detailed descriptions of some chemical methods of detection, e . g . , pre- and post-chromatographic derivatization. Then follows a number of hints to aid the expert chromatographer, including the choice of stationary phase and how to document the results obtained from TLC plates. Part 2 is a very useful and comprehensive list of reagents used to aid detection of components on TLC plates. There is also a description of how these reagents should be used and what results should be expected when detecting particular components. The list is in alphabetical order, and hence is easy to use. There are many useful references in the book, and the index and contents are full and easy to follow as well.Overall, the book is a useful addition to, and complements recent publications in the area of TLC. R. J. Ruane1200 ANALYST, NOVEMBER 1991, VOL. 116 Nuclear Magnetic Resonance in Agriculture Edited by Philip E. Pfeffer and Walter V. Gerasimowicz. Pp. 441. CRC Press. 1989. Price f156.50. ISBN 0-8493- 6864-2. This book is divided into three main sections on in vivo NMR, in vitro NMR and solid-state methods applied to intact polymers and materials. There is also a short final section on NMR imaging. The first section, on in vivo NMR, contains an introduction to high-resolution NMR and an account of its applications, mainly to plants. This is certainly comprehensive, if somewhat uncritical in approach.More specific issues are taken up in the following three chapters, which deal with 31P studies in higher plant cells, metabolism in hypoxic maize root tips and NMR studies of intact seeds. The total section, 112 pages in length, almost makes a complete book in itself and, for giving a snap-shot of the current situation, would be worth having. The next section, on in vitro methods contains four chapters and at 160 pages in length would also represent a small book. The first chapter concerns the use of NMR in the structure determination of plant derived natural products and is really a description of the various solution-state NMR methods that can be used. This is a very readable chapter but, as plant derived chemicals require exactly the same treatment as any other chemicals, one must question why a special chapter is required when there is plenty to read in the literature on this subject.There are also some curious gaps. The two dimen- sional method COSY (homonuclear correlation spectroscopy) is dealt with, but the NOESY (nuclear Overhauser effect spectroscopy) method is not considered, there is also an absence of discussion of many of the newer relayed COSY methods and of the rotating frame Overhauser effect experi- ments. As the latter have proved invaluable in the study of plant polysaccharides this omission is surprising. The next two chapters on photosynthesis and food proteins are both by the same author, Prof. I. C. Baianu, and largely consist of reviews of his own work in these areas. As high resolution NMR of food proteins is not an area where Prof.Baianu has contributed much to the literature lately, the review inevitably perhaps, has a slightly old fashioned air about it. Much of the detail on preparation of cereal proteins is unhelpful and misses the newer classifications that are being developed on the basis of molecular biological approaches. His reports on the CPMAS (cross-polarization magic angle spinning) spectra of cereal proteins also ignore much of the contemporary work that has been carried out on the analysis of these spectra. The next section on water interactions with proteins is by T. F. Kumosinski and H. Pessen. This chapter is really a re-statement of their 1985 review on this subject with some additional material. The area has developed considerably since that time and their analysis, which was, to say the least, heterodox in the original, cannot be said to have persuaded many workers in the mean time. Curiously, it is the very area where Prof. Baianu has been an active publisher of stimulating research and one is left to wonder about the curious choices of authorship. The final section, contains an introduction to solid-state NMR and its applications to the study of soils and related systems, a chapter on cellulose, intact cell wall matrices, wood and lignin, metabolic studies by double cross-polarization methods and a discussion of solid-state NMR methods applied to plant materials. The last section is in effect a review of solid-state methods which makes the introductory chapter rather redundant. (The introductory chapter is also spoilt by having text on pages where the figures referred to are not visible, an unfortunate feature throughout the book, and by some confusion of homogeneous and heterogeneous line shapes.) Other than these problems the section as a whole is quite useful and, again, is of book length. The cost of this book is not high when one considers the total size-it is, in effect, three short books with an additional chapter. The problem is the unevenness of quality, as separate books the first and third sections with the additional chapter might be worth purchasing, provided the price were suffi- ciently low. The second section would be difficult to recom- mend, the combination of all three sections produces a book containing more than many readers might wish to know and which at best will date quickly. At the asking price it is not a book that can be wholeheartedly recommended. P. S. Belton

ISSN:0003-2654    

DOI:10.1039/AN9911601197

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYST, NOVEMBER 1991, VOL. 116 CUMULATIVE AUTHOR INDEX JANUARY-NOVEMBER I991 Abbas, Nureddin M., 409 Abdallah, Amin M. A., 663 Abollino, Ornella, 1167 AgatonoviC-KuStrin, S., 753 Akiyama, Hideaki, 501 Al-Ani, A. M., 1067 Alarie, Jean Pierre, 117 Albero, Ma. Isabel, 653 Alegret, Salvador, 473 Aleixo, Luis M., 947, 1181 Alemany, M. T., 735 Alexiades, Costas A., 361 Alfassi, Zeev B., 35 Ali, M. A., 1067 Aller, A. J., 735 Al-Tamrah, S. A., 183 Altesor, Carmen, 69 Alvarado, Jose, 721 Alvi, S. N.. 405 Alwarthan, A. A., 183 Analytical Methods Committee, 415, 421, 761, Anderson, Fiona, 165 Anderson, Ian G. M., 691 AntonijeviC, Biljana, 477 Anwar, Jamil, 1025 Anzano, Jesus M., 1025 Apak, Regat, 89 Apostolakis, John C., 233 Apparao, N. V. R., 847 Appriou, Pierre, 815 Armfield, Susan J., 569 Arowolo, Toyin A., 595, 1135 Arryanto, Yateman, 1149 Asif, Mohammad, 1071 Askal, Hassan F., 387,861 Asselt, Kees van, 77 Attiyat, Abdulrahman S., 353 Aubeck, Ralph, 811.1001 Avdeeva, Elga N., 715 Aydin, Hasan, 941 Baba, Jun-ichi, 45 Bachas, Leonidas G., 581 Backheet, Enaam Y., 861 Bajic, Stanley J., 1059 Balasubramanian, N., 207 Baldo, M. Antonietta, 933 Banerjee, Amalendu, 95 1 Banerjee, Gopal Chandra, 951 Barcelo, Damia, 681 Bark, L. S., 1149 Barnes, Ramon M., 489 Barnett, Neil W., 701 Basak, Bidyut, 625 Baykut, Fikret, 89 Beaumier, Marc, 1019 Beh, S. K., 459 Belal, F., 1085 Bendtsen, Anders Broe, 647 Bergeron, Mario, 1019 Berlot, Pedro E., 313 Bermejo-Barrera, A., 1033 Bermejo-Barrera, M. P., 1033 Bhattacharya, Utpal, 625 BiCaniC, Dane, 77 Birch, Brian J., 123, 573 Birnie, Albert, 601 Bisagni, E., 159 Blain, Stephane.815 Blais, J., 159 Bodrin. Georgiy V., 715 Bond, A. M., 257 Bontempelli, Gino, 797 Bosque-Sendra, Juan M., 871 Bowyer, James R., 117 Bratinova, Stefanka P., 525 Brauchle, Christoph, 811, 1001 Braven, Jim, 1005 Brinkman, Udo A. Th., 891 Brown, Richard H., 437 Brugman, Anita E., 891 Bull, Christine R., 781 Bunaciu, Andrei A., 239 Cacho, Juan, 399 Camara, Carmen, 1029 Candillier, Marie-Paule, 505 Canesi, Laura, 605 Can0 Pavon, J. M. ,757 Cardwell, Terence J., 253, 1051 Carlos de Andrade, J o ~ o , 905 Carlsson, Jan, 787 Carmona, Manuel, 1075 Cattrall, Robert W., 253, 1051 CaviC-Vlasak, Biljana A., 881 Cavrini, V., 723 Cepeda, A., 159 Cerda, Victor, 913, 1171 Chan, Wing Hong, 39,245 Chang, Hsien-Chang, 793 Chang, Wen-Bao, 213 Chang, Xijun, 965 Chao, Xihuan, 965 Chattaraj, Sarnath, 739 Chattopadhyay, Partha, 1145 Chaurasia, Anupama, 641 Chen, Danhua, 171, 1095 Chen, Guo Nan, 253 Chen, Zeweng, 273 Cheng, Vincent K.W., 957 Cherian, Lata, 667 Cheung, Yu Man, 39 Chiswell, Barry, 657 Christian, Gary D., 1043 Christopoulos, Theodore K., Ci, Yun-Xiang, 213, 297 Ciesielski, Witold, 85 Cladera, Andreu, 913 Clarke, Lionel J., 1121 Cohen, Arnold L., 15 Collins, Kenneth E., 905 Corbini, Gianfranco, 731 Corti, Piero, 731 Cogofre$, Vasile V., 239 Costa-Bauza, A., 59 Covington, Arthur K., 135 Cowan, Faye J., 339 Crane, Michael, 701 Cresser, Malcolm S., 141, 595, Cross, Graeme J., 1051 Cruces Blanco, C., 851 Daily, Simon, 569 Daniele, Salvatore, 933 Das, Arabinda K., 739 Das, Pradip K., 321 Dawson, Bernard S.W., 339 Dawson, Brian, 1063 de Faria, Lourival C., 357 de la Calle Guntiiias, Maria Beatriz, 1029 de la Guardia, Miguel, 1159 de la Torre, M., 81 de Oliveira Neto, Graciliano, De Rosa, Michael, 721 Deacon, Marian, 897 Deb, Manas Kanti, 323 Debayle, Pascal, 409 Dempsey, Eithne , 997 Deorkar, N. V., 961 Desai, M. A., 463, 1113 DeVasto, Joseph K., 443 Devi, Surekha, 825 Diamandis, Eleftherios P., 627 Diaz Garcia, M. E., 1141 Dol, Isabel, 69 Dona, Anne-Marie, 533 Donati, Marco, 933 Donnelly, Garret, 165 627 1135 357,947 Downs, Mark E. A., 569 Dreassi, Elena, 731 Duncan-Hewitt, Wendy C., 881 Dutt, Sachchidananda, 951 Ebdon, Les, 1005 Edmonds, Tony E., 573 Edwards, Anthony C., 601 Efstathiou, Constantinos E., El Taras, M. F., 1085 Elagin, Anatoly, 145 El-Din, M.Sharaf, 1085 Ellis, Andrew T., 333 Emara, Kamla M., 861 Eppelsheim, Christian, 1001 Ertas, F. Nil, 369 Esmadi, Fatima T., 353 Estela, JosC Manuel, 913, 1171 Evans, Denley, 803 Evans, Otis, 15 Farjam, Aria, 891 Favier, Frederic, 479 Favier, Jan-Paul, 77 Feher, Zsofia, 483 Feng, Y. P., 469 Fernindez Muhio, Miguel A., Fernandez-Band, Beatriz, 305 Fernandez-GBmez, F., 81 Fernandez-Romero, J. M., 167 Ferreira, Mhica, 905 Ferris, Marie M., 379 Fleming, Paddy, 195, 909 Florido, Antonio, 473 Fogg, Arnold G., 249, 369, 573, Forteza, Rafael, 1171 Fouques, Dominique, 529 Frampton, Nicholas C., 1005 Fu, Chengguang, 621 Fung, Waikwong, 751 Gaind, Virindar S., 21 Garcla de Torres, A., 757 Garcia Mateo, J. V., 327 Garcia Sanchez, F., 851 Garcla-Olalla, C., 735 Garrigues, Salvador, 1159 Georgiou, Constantinos A., 233 Gielen, Johannes W.J., 437 Glab, Stanislaw, 453 Godinho, Oswaldo E. S., 947, Gomez, Enrique, 913 Goodlet, G., 469 Gordon, Rhea L., 511 Gosavi, Kalpana , 1011 Gowing, Charles J. B., 773 Grases, F., 59 Gratteri, P., 723 Grayeski, Mary Lynn, 443 Griepink, Bernardus, 437 Guitart, Ana, 399 Gupta, V. K., 391, 667 Gushikem, Yoshitaka, 281 Guzman, Miguel, 1043 Hafez, Medhat Abd El-Hamied, 663 Haggett, Barry G. D., 569 Hamilton, Ian C., 253 Hampp, Norbert, 811, 1001 Handel, Henri, 815 Hansen, Elo Harald, 647 Harper, Alexander, 149 Harris, N. K., 469 Hart, John P., 123, 803, 991 Hase, Ushio, 835 Hasegawa, Kunihiko, 821 Haskins, Neville J., 901 Haswell, Stephen J., 333 Hatfield, Christine , 1043 373 269 63 1 1181 1201 Haukka, Suvi, 1055 Hawke, David T., 333 Hayashi, Hidenori, 923 Hazra, Banasri, 951 HCbert, AndrC, 1019 Hemmila, Ilkka, 1155 Hendrix, James L., 49 Hernandez Cordoba, Manuel, Hernandez Orte, Puri, 399 Hight, Susan C., 1013 Himberg, Kimmo, 265 Hiratani, Kazuhisa, 923 Hironaka, Takashi, 695 Hitchman, Michael L., 1131 Hocquellet, Pierre, 505 Hofstetter, Alfons, 65 Hollander, Jacobus C.Th., 437 Holttinen, Sirkku, 1155 Hong, Jian, 213 Hong, Pingkay, 751 Hong, Sung O., 339 Hozumi, Masami, 1037 Hua, Chi, 929, 1117 Hulanicki, Adam, 453 Husager, Lars, 691 Husain, Sajid, 405 Ibrahim, F., 1085 Imai, Kazuhiro, 609 Imasaka, Totaro, 1037 Ioannou, Pinelopi C., 373 Ionescu, Mariana S., 239 Ishibashi, Mumio, 609 Ishibashi, Nobuhiko, 1037 Ishida, Junichi, 301 Ishida, Ryoei, 199 Islam, M.M., 469 Israel, Yecheskel, 489 Ivanova, Christina R., 525 Jab, M. S., 743 Jacobs, Betty J., 15 Jain, Archana, 641 Jain, M. C., 847 Jana, Nikhil R., 321 Jaselskis, Bruno , 1059 Jqdrzejewski, Wlodzimierz, 85 Jerrow, Mohammad, 141 Jiang, Jian, 395 Jie, Niaqin, 395 Jin, Shunyu, 1189 Jones, Michael H., 449 Jordan, Phillip H., 991 Jorge, Manuel, 1117 Kabachnik, Martin I., 715 Kakizaki, Teiji, 31 Kalpana, G., 847 Kaneko, Kentaro, 1185 KapetanoviC, V., 1175 Kataky, Ritu, 135 Kaveeshwar, Rachana, 667 Keating, Paula, 165 Keramidas, Vissarion Z., 361 Khan, Shaukat H., 585 Kharoaf, Maher A., 353 Khopkar, S. M., 961 Kielbasinski, Piotr, 85 Kipling, Arlin L., 881 Kirschenbaum, Louis J., 1167 Knochen, Moises, 69 Kolbe, Ilona, 483 Kolotyrkina, I. Ya., 707 Koncki, Robert, 453 Konishi, Tetsuro, 261 Konstantianos, Dimitrios G., Koshizaki, Naoto, 923 Koshy, Valsamma J., 847 Koupparis, Michael A., 233 Krylova, Svetlana A., 715 Kubota, Lauro T., 281 517, 831 3731202 Kudzin, Zbigniew H., 85 Kumar, B.S. M., 207 La Porta, E., 723 Lam, Yuet W., 957 LamLeung, Svei Y., 957 Lan, Chiren, 35 Landry, Jacques, 529 Langelaan, Fred G. G. M., 437 Laskar, Subrata, 625 Latawiec, Adam P., 749 Lauriault, Ginette, 1063 Lhzaro, F., 81 LeBelle, Michael J., 1063 Lee, Albert Wai Ming, 39, 245 Lee, Yishiuan, 615 Leonard, Michael A., 379 Leonard, Raymond G., 897 Li, Huiping, 727 Li, Jie, 309 Lin, Changshan, 277 Lin, Chenghuang, 1037 Lin, Liming, 919 Linares, Pilar, 305 Lingeman, Henk, 891 Liu, Daojie, 497 Liu, Renmin, 497 Liu, Shaopu, 95 Liu, Weiping, 273 Liu, Xuezhu, 277 Liu, Zhaolan, 213 Liu, Zhongfan, 95 Locascio, Guillermo A., 313 Lopez, Eugenia, 871 Lopez Garcia, Ignacio, 517, 831 Lovgren, Timo, 1155 Lu, Qiongyan, 273 Lu, Xiaohu, 747 Lubbers, Marcel, 77 Lucas, S., 463 Lukac, Sava R., 1195 Luo, Xingyin, 965 Luque de Castro, M.D. , 81, 167, 171, 305, 1095 Lyons, David J., 153 McCallum, Leith E., 153 McDonnell, M. B., 463 McLaughlin, Kieran, 11 17 MacLaurin, Paul, 701 Madrid, Yolanda , 1029 Mahuzier, G., 159 Malvankar, Purnima L., 1081 Mandal, Dinabandhu, 951 March, J. G., 59 Marquez, Manuel, 721 Marr, Iain, 141 Marsel, Joie, 317 Martinez Calatayud, J., 327 Martinez-Lozano, Carmen, 857 Masuda, Toshihiko, 501 MatoviC, Vesna, 477 Matsue, Tomokazu, 793 Matthies, Dietmar, 65 Mattusch, Juergen, 53 Mazzocchin, Gian A., 933 Mazzucotelli, Ambrogio, 605 Meaney, Mary P., 1117 Menjyo, T., 257 Mentasti, Edoardo, 1167 Mesley, Robert J., 975 Metcalf, Richard C., 221 Mikolajczyk, Marian, 85 Miller, James N., 3 MilosavljeviC, Emil B., 49 Milovanovi6, Lj., 1175 Minggang, Lu, 747 Mishra, Neera, 323 Mishra, Rajendra Kumar, 323 Mitchell, Robert, 901 Mitrakas, Manassis G., 361 Miyaki, Yoshinori, 821 Molina, Francisca, 871 Moody, G.J., 459,469 Moreira, JosC C., 281 Moreira, Josino C., 249, 369 Morimoto, Kazuhiro, 27 Moritz, Werner, 589 Motomizu, Shoji, 695 Mueller, Helmut, 53 Mukhtar, Sarfraz, 333 Mukkala, Veli-Matti, 1155 Muller, Lothar, 589 Muiioz de la Peiia, Arsenio, 291 Nagaosa, Y., 257 Nageswara Rao, R., 405 Nakagawa, Genkichi, 45 Nakamura, Masaru, 301 Nakatani, Helena S ., 947 Nambiar, O.G.B., 1011 Nathan, S. S., 1145 Nedeljkovid, Mirjana, 477 Nelson, John H., 49 Nesterova, Nina P., 715 Neto, Graciliano Oliveira, 1181 Nicholas, C. V., 463 Nicholson, Patrick E., 135 Nieuwenhuize, Joop, 347 Niinivaara, Kauko, 265 NikoliC, Sneiana D., 49 Nobbs, Peter E., 153 Norasiah, S . , 743 Nose, Kazuko, 711 Nucci, Lamberto, 731 Nukatsuka, Ishoshi, 199 O’Connell, Gregory R., 1051 O’Dea, John, 195 O’Fagain, Ciaran, 929 O’Halloran, Kelvin R., 657 Ohzeki, Kunio, 199 Ojanpera, Ilkka, 265 Okada, Tatsuhiro, 923 O’Kennedy, Richard, 165 Omar, Nabil M., 387 Ortiz Sobejano, Francisca, 517, Osborne, William J., 153 Oscarsson, Sven, 787 Oshima, Mitsuko, 695 Ozsoz, Mehmet, 997 Pal, Tarasankar, 32 1 Pilivan, Cornelia, 239 Pambid, Ernest0 R., 409 Papeschi, G., 723 Parker, David, 135 Parker, Glenda F., 339 Parry, Susan J., 1071 Pascal, Jean Louis, 479 Pasquini, Celio, 357, 841 Patel, Khageshwar Singh, 323 Patel, R.V., 847 Peck, David V., 221 Peddy, Rao V. C., 847 PCrez Parajon, J., 1141 PCrez Pavon, Jose Luis , 1043 PCrez-Bendito, Dolores, 1075 Pkrez-Ruiz, Tomas, 857 Petrucci, Giuseppe, 1025 Petrukhin, Oleg M., 715 Petty, John D., 1051 Pharr, Daniel Y., 511 Pickral, Elizabeth A., 511 Pinto, Ivan, 285 Pinzauti, S . , 723 Pocklington, W. Dennis, 975 Poley-Vos, Carla H., 347 Polikarpov, Yury M., 715 Polosuchina, Irena B., 715 Ponzano, Enrica, 605 Popova, Sijka A., 525 Porta, Valerio, 1167 Potts, Philip J., 773 Powell, Francis E., 631 Price, Richard J., 1121 Prince, Patrick K., 581 Proctor, Christopher J., 691 Prognon, P., 159 Prownpuntu, Anuchit, 191 Pungor, Erno, 483 Purohit, Rajesh, 825 Putatunda, Anuva, 951 Rader, Jeanne I., 1013 RaduloviC, D., 753 Rahman, I.Ab., 743 83 1 ANALYST, NOVEMBER 1991, VOL. 116 Raimundo Jr., Ivo M., 947, RajakoviC, Ljubinka V., 881 Ramanathan, Subramaniam, Rao, Bh. Gopal, 867 Ravindranathan, T., 1011 Rees, Glan, 803 Rios, Angel, 171 Rivaro, Pao!a, 605 Robards, Kevin, 549 Robles, L. C., 735 Rodriguez Gonzalo, Encarnacion, 1043 Rogatinskaya, Svetlana L., 715 Rohwedder, Jarbas JosC Rodrigues, 841 Romagnoli, R., 937 Roianska, Barbara, 521 Ruan, Chuanmin, 99 RdiiEka, Jaromir, 1043 Sagar, Kamal A., 1117 Sakai, Tadao, 187 Sakurada, Osamu, 31 Saleh, Gamal A., 387, 861 Saleh, M. I. , 743 Salinas, Francisco, 291 Sanchez, Catalina, 653 Sanchez Rojas, F., 757 Sanchez-Pedreiio, Concepcion, Santoni, G., 723 Sanz-Medel, A., 1141 Sargi, L., 159 Sarkar, Mitali, 537 Sarzanini, Corrado, 1167 Saunders, Kevin J., 437 Savard, CCline, 1063 Schiavon, Gilberto, 797 Sciarra, Gianfranco, 731 Scollary, Geoffrey R., 253, 1051 Scullion, S.Paul, 573 Selnau, Henry E., 511 Sepaniak, Michael J., 117 Sharma, Devender K., 867 Sharma, Narendra K., 867 Sherigara, B. S . , 285 Shi, Yingyo, 273 Shijo, Yoshio, 27 Shinde, Vijay M., 541, 1081 Shivhare, Priti, 391 Shpigun, L. K., 707 Si, Zhi-Kun, 309 Silva, Manuel, 1075 Simal Lozano, Jesus , 269 Simonovska, Breda, 317 Singh, Raj P., 409 Slater, Jonathan M., 1125 Smyth, Malcolm R., 897, 929, Soledad Duran, Maria, 291 Soledad Garcia, Ma., 653 Somasiri, Loku L. W., 601 Song, Yujun, 1189 Soutar, Ian, 671 Stoyanoff, Robert E., 21 Straws, Eugen, 77 Su, Zhixing, 965 Suetomi, Katsutoshi, 261 Sugawara, Kazuharu, 131 Sugihara, Hideki, 923 Sultan, Salah M., 177, 183 Sundaramurthi, N.M., 541 Swanson, Linda, 671 Tabata, Masaaki, 1185 Taga, Mitsuhiko, 31, 131 Takahashi, Hitoshi, 261 Takeda, Kikuo, 501 Takeda, Yasushi, 609 Tan, G. H., 941 Tanaka, Shunitz, 31, 131 Tatehana, Miyoko, 199 Thaku, Hari K., 867 Thomas, J. D. R., 459,469 Thompson, Michael, 881 Thompson, Robert Q., 117 1181 1131 653 997, 1117 Tikhomirov, Sergei, 145 Titapiwatanakun, Umaporn, Tom&, Virginia, 857 Tong, Po Lin, 245 Toniolo, Rosanna, 797 Townshend, Alan, 701 Toyo’oka, Toshimasa, 609 Troll, Georg, 65 Tsai, Suhjen Jane, 615 Tsang, Kwok Yin, 245 Tseng, Chia-Liang, 35 Tsysin, G. I., 707 Tutem, Esma, 89 Tuzhi, Peng, 727 Uchida, Isamu, 793 Udupa, H.V. K., 285 Uehara, Nobuo, 27 Ueno, Akinori, 793 Ureiia Pozo, M. E., 757 Vadgama, P., 463, 1113 Val, Otilia, 857 Valchrcel, Miguel, 81, 171, 305, ValdCs-Hevia y Temprano, M. van Delft, Wouter, 347 van den Akker, Adrianus H., van den Berg, Constant M. G., van Rensburg, Sophia D. Janse, van Staden, Jacobus F., 807 Vandendriessche, Stefaan, 437 Vasiljevii, M., 753 Vazquez, M. L., 159 Verchere, Jean-Fraqois, 533 Verma, Archana, 641 Verma, Balbir C., 867 Verma, Krishna K., 641 Vetere, V. F., 937 Viarengo, Aldo, 605 Vo-Dinh, Tuan, 117 Volynsky, Anatoly, 145 Vuori, Erkki, 265 Wada, Hiroko, 45 Wahdan, Tarek M. Abd El-Fatah, 663 Walker, Ronald F., 975 Wang, Dongjin, 1189 Wang, Fang, 297 Wang, Joseph ,997 Waris, Matti, 265 Watt, Esther J., 1125 Werner, Gerhard, 53 Wilson, B. William, 449 Winefordner, James D., 1025 Worsfold, Paul J., 549, 701 Wotring, Vanessa J., 581 Wring, Stephen A., 123 Wu, Qinglian, 1189 Wu, Weh S., 21 Xie, Zenghong, 1189 Xu, Qiheng, 99 . Xu, Yongyuan, 1155 Yamada, Hiroshi, 793 Yamaguchi, Masatoshi, 301 Yamaguchi, Tokio, 501 Yang, Mohsiung, 35 Yebra-Biurrun, M. C. , 1033 Yoshimura, Kazuhisa, 835 Yoshioka, Hiroe, 821 Yuchi, Akio, 45 Zenki, Michio, 711 Zhan, Guangyao, 965 Zhang, Xiao-song, 277 Zhao, Guiwen, 747 Zhao, Naixin, 919 Zhao, Yi, 621 Zhong ing, Yang, 727 Zhu, 8 uiyun, 309 Zhukov, Alex F., 715 ZivanoviC, Lj., 753 Zolotov, Yury A., 707 Zotti, Gianni, 797 191 1095 C., 1141 347 585 807

ISSN:0003-2654    

DOI:10.1039/AN9911601201

出版商:RSC    

年代:1991

数据来源: RSC