5－Br－PADAP作指示剂络合滴定法连续测定矿石中的锌和铜

本文在ｐＨ５．５的乙酸－乙酸钠介质中，对以５－Ｂｒ－ＰＡＤＡＰ作指示剂络合滴定法连续测定锌和铜进行了研究，对滴定的ｐＨ值及指示剂用量进行了选择，试验了锌、铜不同配比的滴定结果，研究了共存离子的干扰。实验表明，用５－Ｂｒ－ＰＡＤＡＰ作指示剂、ＥＤＴＡ作滴定剂连续测定锌和铜，滴定终点颜色变化敏锐，准确度高，锌和铜均在０～２０ｍｇ范围内与ＥＤＴＡ用量成正比，锌、铜比例在１：１０～１０：１范围内相互无影响，方法用于标样及金矿中锌、铜的连续测定，结果满意。     

5—Br—PADAP作指示剂络合滴定法连续测定矿石中的锌和铜

本文在ｐＨ５．５的乙酸－乙酸钠介质中，对以５－Ｂｒ－ＰＡＤＡＰ作指示络合滴定法连续测定锌和铜进行了研究，对滴定的ｐＨ值及指示剂用进行了选择，试验了锌，铜不同配比的滴定结果，研究了共存离子的干扰。实验表明，用５－Ｂｒ－ＰＡＤＡＰ作指示剂，ＥＤＴＡ作滴定剂连续和铜，滴定点颜色变化敏锐，准确度高，锌和铜均在０－２０ｍｇ范围内与ＥＤＴＡ用量成正比，锌，铜比例在１：１０－１０：１范围内相互无影响。方法用于标     

1—（—5—溴—2—吡啶偶氮）—2—萘酚—6—磺酸作指示剂络合滴定连续测定铝 …

在酸性溶液中加入对铝、钛过量的ＥＤＴＡ标准溶液,在ＰＨ４．０煮沸下,铝（Ⅲ）、钛（Ⅳ）与ＥＤＴＡ生成稳定的络合物。以５－Ｂｒ－ＰＡＮ－Ｓ作指示剂,用到铜标准溶液返滴定过量的ＥＤＴＡ,铝钛合量,再用置换法测定钛的量。终点变色敏锐,准确度高,方法用于硅酸盐矿物中铝钛的连续测定,结果满意。     

配位滴定法连续测定铁铝钛的研究及应用：5Br—PADAP作指示剂

以５－Ｂｒ－ＰＡＤＡＰ作指示剂，ＰＨ１．８－２．２ＥＤＴＡ滴定铁（Ⅲ）；用过量的ＥＤＴＡ在ＰＨ３煮沸下与钛和铝生成稳定的配合物，再以苦杏仁酸，氟化钾分别置换Ｔｉ－ＥＤＴＡ，Ａｌ－ＥＤＴＡ配合物中的ＥＤＴＡ，用硫酸铜回滴法于ＰＨ４．８分别测定钛和铝。     

1—（5—溴—2—吡啶偶氮）—2—萘酚—6—磺酸与铁（Ⅱ）显色反应的研究及其应用

本研究了１－（５－溴－２－吡啶偶氮）－２－萘酚－６－磺酸（５－Ｂｒ－ＰＡＮ－Ｓ）与铁（Ⅱ）的显色反应，试验表明，在ｐＨ３－１０范围内铁（Ⅱ）与５－Ｂｒ－ＰＡＮ－Ｓ型成稳定的络合物，络合物在５５０ｎｍ和７５０ｎｍ有二个吸收峰，其表现摩尔吸光系数分别为２．３１×１０＾４和１．７７×１０＾４Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１。络合物组成比为铁（Ⅱ）：５－Ｂｒ－ＰＡＮ－Ｓ＝１：２，络合物稳定常数为１．８２     

膜富集分光光度法测定微量锌

以５－Ｂｒ－ＰＡＤＡＰ为显色剂，用ＷＸ型混合纤维素滤膜（孔径０．６５μｍ，φ２５ｍｍ）富集微量锌，用乙醇溶解富集物（Ｚｎ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ）分光光度法测定锌，Ｚｎ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ在乙醇溶液中最大吸收波长为５５５ｎｍ，表观摩尔吸光系数１．０９×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，锌量在０．１～５．０μｇ／５ｍＬ，范围内符合比耳定律，本法灵敏度高，操作简便，应用于食品，水样中锌     

用分光光度法连续测定血清中微量铜、锌的研究

研究了在ＴｒｉｔｏｎＸ－１００存在下,在ＰＨ８．０的乙醇介质中,用５－Ｂｒ－ＰＡＤＡＰ作为显色剂,应用分光光度法连续测定血清中的铜,锌。本法具有较高的灵敏度,Ｃｕ＾２＋－５－Ｂｒ－ＰＡＤＡＰ的ε为８．５０＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,Ｚｎ＾２＋－５－Ｂｒ－ＰＡＤＡＰ的ε为９．６５＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。铜线性范围为０－０．４５ｍｇ．Ｌ＾－１,锌线性范围为０－０．４０ｍｇ．     

导数光谱法同时测定污水中微量铜和锌

本文研究了以５－Ｂｒ－ｐＡＤＡＰ作显色剂，利用三阶导数光谱法，在碱性介质中同时测定铜和锌。该法测得铜、锌的表观三阶导数摩尔吸光系数分别为１．０×１０￣５和３．０×１０￣５，同时解决了谱带相互重叠干扰的问题。对石油化工厂污水进行测定，得到满意结果。     

5-Br-PADAP-NO2--SCN-三元离子缔合物分光光度法测定微量NO2-的研究

研究了在硫酸介质中５－Ｂｒ－ＰＡＤＡＰ与ＮＯ＾－２和ＳＣＮ＾－形成三元离子缔合物的最佳条件,其表观摩尔吸光系数ε５５０＝２．４＊１０＾４Ｌ／（ｍｏｌ．ｃｍ）,缔合物组成比为ｎ（５－Ｂｒ－ＰＡＤＡＰ）：ｎ（ＮＯ＾２）：ｎ（ＳＣＮ＾＿＝１：１：１。     

水溶性新显色剂5-Br-PADN-S的制备与分析特性的研究及其用于锌的测定

报道了水溶性 １－（５－溴－２－吡啶偶氮）－２,７－萘二酚－６－磺酸（５－Ｂｒ－ＰＡＤＮ－Ｓ）的制备方法及其分析特性。研究了此试剂与锌（Ⅱ）等金属离子在水溶液中直接测定的显色反应,在ｐＨ １０．０～１１．４ 的Ｎａ２Ｂ４Ｏ７～ＮａＯＨ 缓冲溶液中,５－Ｂｒ－ＰＡＤＮ－Ｓ与锌（Ⅱ）形成２∶１ 的紫色配合物,最大吸收波长位于５４２ ｎｍ ,表观摩尔吸光系数ε５４２＝ ６．３８×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ）,锌量在０～２０ ｍ ｇ／１０ Ｌ范围内符合比耳定律。在掩蔽剂的存在下,用于人发、奶粉及矿石等试样中锌的测定,结果与ＡＡＳ法一致。     

1-(2-噻唑)-3-(8-(5-对磺酸基苯基偶氮)喹啉)-三氮烯的合成及其与铜(Ⅱ)的显色反应

合成了新试剂1-(2-噻唑)-3-(8-(5-对磺酸基苯基偶氮)喹啉-三氮烯(TCPQT),并研究了其与Cu2+的显色反应。结果表明:在pH 7.5的磷酸盐缓冲溶液中,TCPQT与Cu2+形成摩尔比为1:1的紫红色络合物,该络合物在606.5nm处有一最大吸收峰,其表观摩尔吸光系数为3.36×105L.mol-1.cm-1,Cu2+的质量浓度在0～0.4μg/mL范围内符合比尔定律,相关系数r=0.9993。方法已用于测定食品中的微量铜。     

Spectrophotometric determination of zinc in copper-base alloys with TAN

TAN reacts with zinc(II) forming a red complex with composition 1:2 Zn(II)-TAN and absorption maximum at 582 nm. Zinc can be determined with this reagent in the presence of Triton X-100, in the pH range 6.20-8.00 with a molar absorptivity of 4.5×10⁴ l/mol/cm Beer's Law was obeyed up to least 1.55 g/ml. Copper interference was eliminated with a mixture of thiosulfate and ascorbic acid and nickel separated by precipitation with dimethylglyoxime. The proposed method was used for zinc determination in several copper-base alloys and the results of analysis in comparison with certified values indicated that the procedure was accurate and precise. A derivative procedure is also proposed, allowing zinc determination with high sensitivity (5-400 ng/ml).     

Adsorptive Preconcentration for Voltammetric Measurements of Trace Level of Iron (III) With 2- (2- Thiazolylazo)-4-Methylphenol

Abstract

This paper describes an electrochemical stripping procedure for ultratrace measurements of iron, in which preconcentration is achieved by the adsorption of a iron-[2-thiazolylazo)-4- methyl phenol] complex onto a static mercury drop electrode Cyclic voltammetry was used to characterize the interfaciai and redox behavior. For a 5 minute preconcentration time, the detection limit found was 1.8 × 10^?0mol/1. Optimum experimental conditions were found by the use of a stirred triethanolamine (pH 8.6) solution with 2-[2-thiazolylazo- 4- methyl phenol] concentration of 1.0 × 10^?5 mol/1, a preconcentration potential of ?0.46V and linear scan mode. With preconcentration for 30 sec., calibration plots for iron are linear for the 5–29 μ g/1 range. Possible interferences by masking agents and several trace ions have been investigated. The interference of copper and uranium are eliminated by addition of CyDTA and carbonate ion respectively. Simultaneous determination of iron with copper and nickel is possible. The merits of the aforementioned procedure are demonstrated in the analysis of fresh water.     

2-(3,5-二溴-2-吡啶偶氮)-5-二乙氨基苯酚作络合滴定指示剂连续测定铁和铝

对2-(3,5-二溴-2-吡啶偶氮)-5-二乙氨基苯酚作铁(Ⅲ),铜(Ⅱ)的配位滴定指示剂进行了研究.在pH1.8～2.0时用EDTA标准溶液滴定铁(Ⅲ).在滴定铁(Ⅲ)后的溶液中,加入对铝过量的EDTA标准溶液,在pH3.8～4.0煮沸下,铝(Ⅲ)与EDTA生成稳定的络合物,过量的EDTA用硫酸铜标准溶液滴定,从而测定铝(Ⅲ).     

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.     

Pre-concentration procedure for determination of copper and zinc in food samples by sequential multi-element flame atomic absorption spectrometry

In this paper is proposed a simultaneous pre-concentration procedure using cloud point extraction for the determination of copper and zinc in food samples employing sequential multi-element flame atomic absorption spectrometry (FS-FAAS). The reagent used is 1-(2-pyridylazo)-2-naphthol (PAN) and the micellar phase is obtained using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) and centrifugation. The optimization step was performed using Box-Behnken design for three factors: solution pH, reagent concentration and buffer concentration. A multiple response function was established in order to get an experimental condition for simultaneous extraction of copper and zinc. Under the optimized experimental conditions, the method allows the determination of copper with a limit of detection (3sigma(b)/S, LOD) of 0.1 microg L(-1), precision expressed as relative standard deviation (R.S.D.) of 2.1 and 1.3% (N=10), for copper concentrations of 10 and 50 microg L(-1), respectively. Zinc is determined with a LOD of 0.15 microg L(-1) and precision as R.S.D. of 2.7 and 1.7% for concentrations of 10 and 50 microg L(-1), respectively. The enhancement factors obtained were 36 and 32 for copper and zinc, respectively. The accuracy was assessed by analysis of certified reference materials, namely, SRM 1567a - Wheat Flour and SRM 8433 - Corn Bran from National Institute of Standards & Technology and BCR 189-wholemeal flour from Institute of Reference Materials and Measurements. The method was applied to the determination of copper and zinc in oats, powdered chocolate, corn flour and wheat flour samples. The copper content in the samples analyzed varied from 1.14 to 3.28 microg g(-1) and zinc from 8.7 to 22.9 microg g(-1).     

Synergistic extraction and spectrophotometric determination of copper(II) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol: analysis of alloys, pharmaceuticals and biological samples

A simple and selective spectrophotometric method was developed for the determination of copper(II) with 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol [2',4'-dinitro APTPT] as a chromogenic reagent. The procedure was based on the synergistic extraction of copper(II) with 2',4'-dinitro APTPT in the presence of 0.5 mol L(-1) pyridine to give green colored ternary complex of a molar ratio 1:2:2 (M:L:Py) in the pH range 8.7-10.5. It exhibits a maximum absorption of colored complex at 445 nm and 645 nm in chloroform against the reagent blank. Beer's law was followed in the concentration range 10-80 μg mL(-1) of copper(II) and optimum range of 20-70 μg mL(-1) the metal as evaluated from Ringbom's plot. The molar absorptivity and Sandell's sensitivity of copper(II)-2',4'-dinitro APTPT-pyridine complex in chloroform are 0.87×10(3) L mol(-1)c m(-1) and 0.072 μg cm(-2), respectively. The interfering effects of various cations and anions were also studied, and use of suitable masking agents enhances the selectivity of the method. The proposed method is rapid, reproducible and successfully applied for the determination of copper(II) in binary and synthetic mixtures, alloys, pharmaceutical formulations, environmental and fertilizer samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer also tested the validity of the method.     

Determination of transition metal ions in tobacco as their 2-(2-quinolinylazo)-5-dimethylaminophenol derivatives using reversed-phase liquid chromatography with UV-VIS detection

This paper reports the utilization of solid-phase extraction and the reversed-phase high-performance liquid chromatography for the determination of six important transition metal ions: iron, cobalt, nickel, copper, zinc and manganese in tobacco with 2-(2-quinolinylazo)-5-dimethylaminophenol (QADMAP) as chelating reagent. Iron, cobalt, nickel, copper, zinc and manganese ions react with QADMAP to form colored chelates in the medium of acetic acid-sodium acetate buffer solution (pH 4.0). These chelates can be enriched by solid-phase extraction with Waters Sep-Pak-C18 cartridge, and eluted the retained chelates from cartridge with tetrahydrofuran. The chelates were separated on a Waters Nova-Pak-C18 column (150x3.9 mm, 5 microm) by gradient elution with methanol (containing 0.5% of acetic acid) and 0.05 mol/l pH 4.0 acetic acid-sodium acetate buffer solution as mobile phase at a flow-rate of 0.5 ml/min. The detection limits of iron, cobalt, nickel, copper, zinc and manganese are 10, 12, 8, 13, 17 and 22 ng/l, respectively. This method had been applied to the determination of iron, cobalt, nickel, copper, zinc and manganese in tobacco with good results.     

用靛蓝胭脂红-H_2O_2流动注射化学发光法测定水样中的铜(Ⅱ)

在Na2CO3-NaHCO3缓冲溶液中,铜(Ⅱ)对H2O2氧化靛蓝胭脂红的反应具有明显的催化作用.基于此,结合流动注射技术,建立了测定铜(Ⅱ)的化学发光新方法;研究了影响化学发光强度的各种因素.结果表明,在最佳试验条件下,铜(Ⅱ)浓度在1.0×10-8"1.0×10-5 mol·L-1范围内与发光强度呈线性关系,检出限为4.1×10-10 mol·L-1.将该方法用于水样中铜(Ⅱ)的测定,结果满意.