SPECTROPHOTOMETRIC DETERMINATION OF SULFATE ION THROUGH COPPER(II)-AZIDE SYSTEM

被引：5
|
作者：
GUIMARAES, OM
DEANDRADE, JF
NEVES, EA
CHIERICE, GO
机构：
[1] UFSCAR,DEPT QUIM,BR-13560 SAO CARLOS,SP,BRAZIL
[2] USP,IFQSC,DEPT QUIM & FIS MOLEC,BR-13560 SAO CARLOS,SP,BRAZIL
来源：
ANALYTICAL LETTERS | 1993年 / 26卷 / 11期
基金：
巴西圣保罗研究基金会;
关键词：
SPECTROPHOTOMETRY; SULFATE DETERMINATION; COPPER-AZIDE-SULFATE SYSTEM; EQUILIBRIUM CONSTANTS;
D O I：
10.1080/00032719308017486
中图分类号：
O65 [分析化学];
学科分类号：
070302 ; 081704 ;
摘要：
An indirect and alternative method for the determination of sulfate ion has been established by spectrophotometry. The procedure is based on the formation of copper(II) monoazido species, in water/acetone medium, in which a discoloration effect of system is caused by sulfate presence. In the recommended conditions, sulfate ions can be determined in the concentration range from 40 to 5000 mg/l (ppm), at 375 nm, in natural samples of waters. The best experimental conditions were determined analysing the different factors involved. Studies about the formation equilibria of the CuN3+ and CuSO4 species were realized in water and their respective stability constants (beta1 = 225 M-1 and 7.15 M-1) were determined by spectrophotometry at 25.0-degrees-C and ionic strength 1.0 M (NaClO4). Equilibrium investigations were also made in presence of acetone. Additional studies on the ternary system Cu(II)/N3-/SO42-) indicated some evidences of mixed complexes.
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页码：2491 / 2501
页数：11
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