Abstract
The ion-pair extraction of univalent copper with 3,6-dithiaoctane in the presence of each of 15 univalent anions into a small volume of chloroform at a pH of less than 7 was studied. Of these anions, picric acid, Bromothymol Blue, and cobalt(III)-dihydroxyazobenzene complex gave a quantitative extraction of copper (>99%) and Bromocresol Green, EO, PO, and Co-5-Br-PAPS complex a constant, but a slightly lower, extraction (85 - 95%) at their corresponding pH ranges, respectively. The direct nebulization of 50 µL of the chloroform extract into a fuel-lean air-acetylene flame gave a sensitive signal height without any background correction from chloroform. The present method was successfully applied to the determination of copper in three standard botanical, one standard zoological, and four standard geological reference materials.
