The Determination of Trace Amounts of Cadmium in Rice Samples by Dual-wave Length Spectrophotometry——cd(Ⅱ)-Cadion 2B-Tween 40 System

The optimal conditions of the Cd(Ⅱ)-Cadion 2B-Tween 40 system have been studied.In the alkaline medium of NaOH,a red Cd(Ⅱ)-Cadion 2B-Tween 40 complex forms with e510nm=9.80×104 The Ka ofCadion 2B and Surface tension in the system was estimated.It was proved that K was increased and the reagent species with absorption maximum at 605nm formed.Using the dual-wave length method at 510?605nm the apparent molar absorptivity for cadmium measured was 2.60×10 The molar ratio of cadmium to Cadion 2B is estimated to be 1:3 as estimated by the molar ratio method and continuous variation method.The Beer's law is obeyed in 0~6μg Cd/25ml.Using the proposed method with TEA,IDA and CIT masking mixture,the Cd content in rice samples was determined with satisfactory results.     

稀土元素及其显色效应的研究 VI:镧-偶氮氯膦III——-钇混合多核配合物的生成

The interference of lanthanum in the spectrophotometric determination of yttrium in the form of β-type complex with chlorophosphonazo III (CPA III) is proved to be a cocoloration effect. It is due to the formation of a mixed polynuclear complex between CPA III and lanthahum-yttrium with a cyclic structure. The composition of the complex has been established to be La:CPA III:Y = 1:2:1 by the method of molar ratio. The optimal conditions for the formation of polynuclear complex and influence factors have also been studied. A "replacement type" reaction is proposed to account for the cocoloration effect.     

SPECTROPHOTOMETRIC STUDY OF BIMETALLIC TERNARY COMPLEX OF LANTHANUM——COPPER WITH ALIZARIN FLUORINE BLUE

The bimetallic ternary complex formation in the aqueous solution of La and Cu with alizarin fluorine blue (AFB) was studied by spectrophotometry.The ternary complex LaCu3(AFB)3 has maximum light absorption at 550nm.The colour reaction selectivity is fairly good and the method can be applied to the direct photometric determination of copper in lanthanum or some pure metals.A new mathematical approach to the treatment of spectrophotometric data for differentiation between mononuclear and polynuclear in solution is presented.The improvable fixed logarithm method is for complexes of the type MmBn(m=n) or MmBn(m=n).We report that La(Ⅲ) combines with AFB at pH 4.5 to form a single complex,withm=n=2,La2(AFB)2.     

4-(2-QUINOLYLAZO)-1, 3-DIHYDROXY-NAPHTHALENE——A NEW SENSITIVE ANALYTICAL REAGENT FOR TRACE COPPER DETERMINATION

The azo compound 4-(2-quinolylazo)-1,3-dihydroxynaphthalene (2-QADNm) has been synthesized and used as a new sensitive spectrophotometric and electroanalytical reagent for determination of trace amounts of copper. In dilute alkaline solutions, 2-QADNm shows a single-sweep polarographic wave at -0.95 V (vs. SCE). In the presence of copper(Ⅱ) two new waves appear at -0.52 and -0.79 V. Using the wave at-0.79 V, a trace amount of copper down to 10~(-8) mol/L can be determined. The electroanalytical characteristics of 2-QADNm and the electrochemical reaction mechanism of the copper(Ⅱ)-2-QADNm complex have been studied in detail by the use of various electrochemical techniques. In alkaline solutions, 2-QADNm forms red complex with copper(Ⅱ) which has an absorption peak at 526 nm, the molar absorptivity being 6.4×10~4 1·mol~(-1)·cm~(-1). In the presence of a non-ionic surfactant the molar absorptivity of this complex is 1.6×10~5 1·mol~(-1)·cm~(-1).     

Determination of Nickel and Palladium in Environmental Samples by Low Temperature ETV-ICP-OES Coupled with Liquid-liquid Extraction with Dimethylglyoxime as Both Extractant and Chemical Modifier

A novel method for the determination of nickel and palladium in environmental samples by low temperature ETV-ICP-OES with dimethylglyoxime(DMG)as both the extractant and chemical modifier has been developed.In this study,it was found that nickel and palladium can form complexes with dimethylglyoxime(0.05%,mass fraction)at pH 6.0 and can be extracted into chloroform quantitatively.The complexes can be evaporated into plasma at a suita-ble temperature(1400 ℃)for ICP-OES detection.Under the optimized conditions,the detection limits of nickel and palladium are 0.48 and 0.40 ng/mL,respectively,while the RSD values are separately 5.0% and 3.1%(ρ=50 ng/mL,n=7).The proposed method was applied to the determination of the target analytes in environmental samples with satisfactory results.     

Simultaneous spectrophotometric determination of cobalt,copper and nickel using 1-（2-thiazolylazo）-2-naphthol by chemometrics methods

The simultaneous determination of cobalt, copper and nickel using 1-（2-thiazolylazo）-2-naphthol （first figure of this article） by spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences. By multivariate calibration methods, such as partial least squares （PLS） regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction （OSC） is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 550-750-nm range for 21 different mixtures of cobalt, copper and nickel. Calibration matrices were formed from samples containing 0.05-1.05, 0.05-1.30 and 0.05-0.80 μg·mL^-1 for cobalt, copper and nickel, respectively. The root mean square error of prediction （RMSEP） for cobalt, copper and nickel with OSC and without OSC were 0.007, 0.008, 0.011 and 0.031,0.037, 0.032 μg· mL^-1, respectively. This procedure allows the simultaneous determination of cobalt, copper and nickel in synthetic and real samples and good reliability of the determination was proved.     

SYNTHESIS OF MESO-TETRA (4-METHOXYPHENYL-3-SULFONATE) PORPHINE AND SPECTROPHOTOMETRIC STUDY OF COLOUR REACTION WITH COPPER

In this paper meso-tetra (4-methoxyphenyl-3-sulpho) Porphine (TMPPS_4) was synthesized and its colour reaction with copper was studied. It was found to be a highly sensitive and highly selective reagent for the direct spectrophotometric determination of ultramicro amount of copper. The apparent molar absorptivity of the complex is 3.72×10~5L/mol·cm. Beer's law is obeyed for Cu(Ⅱ)of 0～1.4μg/10ml. The interference of 21 different ions and 6 kinds of salts were examined and found to be minimal. The complex formation of Cu(Ⅱ) with TMPPS_4 is generally slow at room temperature<<25℃>, but the reaction can be accelerated in the presence of NH_2OH·>HCl and completed within 5min. At PH 5.2 the Soret band of TMPPS_4 overlaps almost completetely with that of the complex. Therefore, the complex formation is taken to completion at this PH. Then the Soret band of TMPPS_4 shifted away from that of the complex by acidification.This simple and rapid method has been successfully applied to the direct determination of Cu in Al-alloys, industrial water, foods and human hair.     

阿莫西林与维多利亚蓝B的显色反应及应用

The color reaction of amoxicillin with victoria blue B was studied.A novel visible spectrophotometric method for the determination of amoxicillin has been established.Under pH 8.50～10.5 condition,victoria blue B reacteds with amoxicillin to form red ion association complex.The maximum absorption wavelength was at 630nm and the apparent molar absorptivity(ε) was 2.67×10~4 L·mol~(-1)·cm~(-1) and the linear ranges was 0～5.5 mg·L~(-1).Amoxicillin obey Beer's law in definite concentration range.The optimum reaction conditions and the methodological precision were studied simultaneity.The method was simple and rapid and sensitive for the determination of amoxicillin.This method has been applied to the determination of amoxicillin is in the city sell amoxicillin medicament is in point and average recovery at 98.2%～101.0%.     

Spectrophotometric Determination of Cimetidine through Charge-transfer Reaction with 1,5-Dichloroanthraquinone as a π-Electron Acceptor

Cimetidine reacting with 1,5-dichloroanthraquinone in acetone solution can produce a charge-transfer complex that shows a strong absorption peak at 343 nm. The absorption value at 343 nm increased with cimetidine concentration in the range of 0.01—0.5 μg/mL, with regression coefficient of 0.9995 and detection limit of 0.006 μg/mL. This simple and sensitive method has been successfully applied to determine cimetidine in tablets and capsules, with average recovery of (98.47±0.92)% and (97.07±1.16)%, respectively. Furthermore, the mole ratio of the complex between cimetidine and 1,5-dichloroanthraquinone is 2∶1, and the mechanism of charge-transfer reaction is explored.     

A novel method for the spectrophotometric determination of cefradine by using sodium nitroprusside as chromogenic reagent

A novel method is developed for the determination of cefradine by using sodium nitroprusside as chromogenic reagent. The experiment indicates that a russety product is formed by the reaction of cefradine with sodium nitroprusside in basic solution, and the maximum absorption wavelength （λmax） of russety product is 505 rim. And the sensitization of tetradecyl benzyl dimethyl ammonium chloride for the reaction of cefradine with sodium nitroprusside is remarkable, The apparent molar absorption coefficient （5505） is 2.81 × 103 L/mol cm. The linear equation isA = 0.0657 ＋ 0.00804C （μg/mL） in the range of 1.50-55.0μg/mL of cefradine with a correlation coefficient r = 0.9992, and the detection limit is 1.38 p,g/mL. This method has been applied to determine cefradine in capsule and tablet samples.     

Extraction and spectrophotometric determination of zinc in coal fly ash and pond sediments with 2-[2-(3,5-dibromopyridyl)azo]-5-dimethylaminobenzoic acid

An extraction-spectrophotometric method is described for the determination of traces of zinc with 2-[2-(3,5-dibromopyridyl)azo]-5-dimethylaminobenzoic acid. The reagent forms a stable, blue 1:2 zinc/reagent complex that can be extracted into chloroform. The apparent molar absorptivity of the zinc(II) complex is 1.26 × 10⁵ l mol^?1 cm^?1 at 610 nm in chloroform. The reagent is relatively selective; interferences from cobalt, copper and nickel can be masked with dimethylglyoxime and aluminium and iron with a mixture of sodium fluoride and triethanolamine. The method is applied to the determination of zinc in coal fly ash and pond sediments with good precision and accuracy.     

Extraction-spectrophotometric determination of trace iron (II) in sea water with 2-[2-(3,5-dibromopyridyl)azo]-5-diethylaminobenzoic acid

An extraction-spectrophotometric method is described for the determination of traces of iron(II) with 2-[2-(3,5-dibromopyridyl)azo]-5-diethyl-aminobenzoic acid. The reagent forms a stable and blue 12 iron/reagent complex that can be extracted into chloroform. The apparent molar absorptivity of the iron(II) complex is 1.09 × 10⁵ 1 mol^–1 cm^–1 at 624 nm in chloroform. The reagent is relatively selective; interferences from cobalt, copper, nickel and vanadium can be removed by using dimethylglyoxime and EDTA. The method is applied to the determination of iron (II) in sea water and aluminium alloys with good precision and accuracy.     

新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸分光光度法测定微量钴

近年来,杂环偶氮苯甲酸类显色剂取得了较快的发展。由于氨基取代结构对试剂性能有较大的影响^[1],因此本文合成了新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸,(TAEB)并研究了它与钴的显色反应。     

2-[2-(6-Methylbenzothiazolyl)azo]-5-Diethylaminobenzoic acid as a new analytical reagent for the spectrophotometric determination of nickel

A new thiazolylazo chromogenic reagent, 2-[2-(6-methylbenzo-thiazoly)azo]-5-diethylaminobenzoic acid (6-Me-BTAEB), has been synthesized. Its chromogenic reaction with microamounts of nickel in the presence of sodium dodecylsulfate (SDS) has been thoroughly studied. 6-Me-BTAEB reacts with nickel(II) in weak acid medium containing appropriate amounts of SDS to form a blue-violet complex with high sensitivity, good selectivity and high stability. The composition is found to be 1:2 (nickel to 6-Me-BTAEB) and its absorption maximum is at 650 nm with an apparent molar absorptivity of 1.67 × 10⁵l mole^–1 cm^–1. Beer's law is obeyed over the range 0-0.4 g of nickel per ml. The proposed method has been applied to the direct determination of nickel in aluminium alloys, pure magnesium and low alloy steels at the 0.2–0.3% (w:w) level with satisfactory results.     

5—（2—苯并噻唑偶氮）—8—氨基喹啉作为镍的光度分析试剂及应用研究

研究了新试剂 5- (2 -苯并噻唑偶氮 ) - 8-氨基喹啉与镍的显色反应。在弱碱性介质中 ,阳离子表面活性剂溴化十六烷基三甲基铵存在下 ,试剂与镍形成 3∶ 1的蓝色配合物 ,其最大吸收波长位于 61 0 nm处 ,表观摩尔吸光系数为 1 .2 6× 1 0 5L· mol-1· cm-1,镍的浓度在 0～ 8.0μg/2 5ml范围内 ,符合比耳定律。应用于铝合金中微量镍的测定 ,获得了满意的结果。     

新试剂5-(2'-氨基-4'-羟基苯偶氮)邻苯二甲酰肼(AHPP) 的合成及其光度法测定钴

本文新试剂5-(2'-氨基-4'-羟基苯偶氮)邻苯二甲酰肼的合成,并研究了该试剂用于光度法测定钴的反应条件,钴与试剂在pH7.7-9.0(0.06mol.L~-1Na~2B~ 4O~ 7-HCI缓冲介质)时形成稳定配合物,最大吸收位于542nm处,摩尔吸光率为5.7×10~L.mol~-~1.cm~-~1,配合物的组成为1:2的Co:AHPP,钴浓度在0-1.02×10~-~4mol.L~-~1范围内符合Beer'slaw.试验了共存离子的影响,发现除Cu(Ⅱ),Ni(Ⅱ)略有干扰(可掩敝)外,其它常见离子均允许大量存在,该法直接用于不锈钢和维生素B~1~2 中钴的测定.     

Sensitive spectrophotometric determination of nickel(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

A simple, selective and highly sensitive procedure for spectrophotometric determination of nickel has been developed. At pH 5.5, nickel reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in water-ethanol medium to form a red-violet complex which has two absorption maxima, at 520 and 56Onm. The molar absorptivity at 56Onm is 1.26 x 10(5) l.mole(-1).cm(-1). Beer's law is obeyed for 0-15 mug of nickel. Nickel in aluminium alloys and electroplating waste-water has been determined by this method.     

Spectrophotometric determination of nickel in biological samples using 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene

A new sensitive and selective chromogenic reagent, 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene (ABHPT), was synthesized. It has been found that ABHPT reacts with nickel(II) in a borax buffer solution (pH 10.0) to form 2: 1 red complexes with the maximum absorption at 530 nm. The apparent molar absorptivity of the complex is 2.6 × 10⁵ L/(mol cm). Most metal ions can be tolerated in considerable amounts, whereby only zinc and mercury may interfere with the determination of nickel(II). Nevertheless, this can be easily eliminated by prior separation with sulfhydryl dextran gel. A new method for the spectrophotometric determination of trace nickel(II) was developed. Beer’s law is obeyed for 0–15 μg of nickel(II) in 25 mL of solution. The limit of quantification, limit of detection, and relative standard deviation are 0.74 ng/mL, 0.25 ng/mL, and 1.0%, respectively. The method has been applied to the determination of trace nickel(II) in biological samples with satisfactory results. The text was submitted by the authors in English.     

Selective determination of cobalt using polyurethane foam and 2-(2-benzothiazolylazo)-2-p-cresol as a spectrophotometric reagent

The present work describes a selective, rapid and economical method for the determination of cobalt using the 2-(2-benzothiazolylazo)-p-cresol (BTAC) as a spectrophotometric reagent associated with a solid extraction on polyurethane foam. The BTAC reacts with Co(II) in the presence of Triton-X100 surfactant forming a green complex with maximum absorption at 615 nm. The reaction is used for cobalt determination within a pH range of 6.50-7.50, with an apparent molar absorptivity of 1.62 x 10(4) L mol(-1) cm(-1). Beer's Law is obeyed for a concentration of at least 1.60 microg ml(-1). A selective procedure is proposed for cobalt determination in the presence of Fe(II), Hg(II), Zn(II) and Cu(II) up to milligram levels using masking agents. Polyurethane foam is used for the preconcentration and separation of cobalt from thiocyanate media and this procedure is applied to its determination in nickel salts and steel alloys.     

8-喹啉偶氮显色剂QADCB的合成及其分析性能的研究

报道了8-喹啉偶氮显色剂2-(8-喹啉偶氮)-5-二羧甲氨基苯甲酸(QADCB)的合成、提纯与鉴定,研究了其与Co(Ⅱ)、Ni(Ⅱ)、Fe(Ⅲ)的显色反应,对QADCB与Co(Ⅱ)的显色反应作了研究。在pH5.9的缓冲体系中,试剂与Co(Ⅱ)形成棕红色配合物,其最大吸收波长位于650nm,表观摩尔吸光系数为4.2×104L.mol-1.cm-1,钴量在0~20μg/25mL范围内符合比耳定律。方法简便、快速,选择性较好,已用于纯铜、维生素B12中微量钴的测定,结果满意。