Successive spectrophotometric determination of iron(III) and copper(II) by the ion-exchange extraction with aluminum cupferrate-chloroform

• Published in: BUNSEKI KAGAKU Vol. 26; no. 7; pp. 502 - 504
• Main Author: SASAKI, Yoshimi
• Format: Journal Article
• Language: Japanese
• Published: The Japan Society for Analytical Chemistry 05.07.1977
• Subjects: Aluminum cupferrate; Copper(II); Ion exchange extraction; Iron(III); Spectrophotometry
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.26.502

Trace amounts of iron and copper were determined spectrophotometrically. Iron(III) and copper(II) were extracted with aluminum cupferrate-chloroform, and the ligand was exchanged with sodium diethyldithiocarbamate for determination of copper. In a separating funnel, an aqueous solution {(2090)ml} containing iron(III) {(10100)μg} and copper(II) {(240)μg} was adjusted to pH 4.04.5 with 1 M acetic acid-sodium acetate buffer solution, and 10.0 ml of 0.01 M aluminum cupferrate in chloroform was added. After the mixture was shaken for 3 minutes, the chloroform phase was divided into two parts: one was taken into a 1.0 cm cell and iron was determined by measuring the absorbance at 400 nm against the reagent blank. The other was transferred into another separating funnel and shaken for about 1 minute with 10 ml of 1 M sodium citrate-sodium hydroxide solution(pH 11). Then 10 ml of 0.04% sodium diethyldithiocarbamate solution was added and the content was shaken again for 30 seconds. The absorbance of the chloroform phase was measured at 436 nm for copper. As small as 0.003% of iron and 0.001% of copper in nickel and cobalt salts ( JIS 1st-grade reagent) could be determined without any perliminary separation of them from the matrix.