Spectrophotometric determination of copper (II) with sodium 2-bromo-4, 5-dihydroxyazobenzene-4'-sulfonate in the presence of cetyltrimethylammonium chloride

WAKAMATSU Yoshinobu

doi:10.2116/bunsekikagaku.25.671

Bibliographic Information

Other Title

塩化セチルトリメチルアンモニウムの存在下，２‐ブロム‐４，５‐ジヒドロキシアゾベンゼン‐４′‐スルホン酸ナトリウムによる銅（ＩＩ）の吸光光度定量
エンカセチルトリメチルアンモニウムノソンザイカ 2 ブロムー4 5 ジヒ
塩化セチルトリメチルアンモニウムの存在下2-ブロム-4,5-ジヒドロキシアゾベンゼン-4'-スルホン酸ナトリウムによる銅(II)の吸光光度定量

Search this article

Description

Sodium 2-bromo-4, 5-dihydroxyazobenzene-4'-solfonate (abbreviated as BDAS) reacts with traces of copper(II) in a neutral medium in the presence of cetyltrimethylammonium chloride (CTMAC) to form a strongly colored ternary complex. The complex has an absorption maximum at 530 nm, and the maximum absorbance was obtained in the pH range from 6.4 to 8.3. The absorbance of the complex was constant provided that the BDAS and CTMAC concentrations were more than 1.0×10^-4 M and 4.0×10^-4 M respectively. Absorbance of the reagent blank was effectively reduced by addition of excessive sodium borate.<BR>The procedure is as follows: Transfer the sample solution containing up to 26 μg of copper(II) to a 25 ml volumetric flask. Add 4 ml of 1×10^-3 M BDAS, 10 ml of 0.2 M phosphate buffer (pH 7.0) containing 0.04 M sodium borate, 3 ml of 0.01 M CTMAC and 2.5 ml of 1 M potassium chloride. Dilute to the mark with water and measure the absorbance at 530 nm using the reagent blank as a reference.<BR>Beer's law was obeyed over the range 026μg of copper(II). The apparent molar absorptivity of the ternary complex is 4.8×10⁴ cm^-1 mol^-1 l at 530 nm, and Sandell's sensitivity is 1.4×10^-3 μg cm^-2. The combining ratio of copper(II) and BDAS in the ternary complex was shown to be 1:2. Iron(III), aluminum, galium, indium, titanium(IV) and molybdenum(VI) interfered with the determination of copper (II) even when present at microgram levels.

Journal

BUNSEKI KAGAKU

BUNSEKI KAGAKU 25 (10), 671-674, 1976

The Japan Society for Analytical Chemistry

Keywords

Details 詳細情報について

Export