Extraction-spectrophotometric determination of nickel as ni-(par)(2)-(ctab)(2) complex in polymetallic sea-bed nodules and steels

A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 mug/ml with a molar absorptivity of 45 200 L . mol-1 . cm-1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04 - 0.127 mug for 5 - 25 mug of nickel.