Spectrophotometric investigation of trace copper and silver complexes witha new chromogenic ligand, o-methylbenzenediazoaminobenzene-p-azobenzene

The synthesis of o-methylbenzenediazoaminobenzene-p-azobenzene (o-MDAP) was made. At pH 12, copper and silver formed a sensitive complex with o-MDAP. The characteristics of copper and silver complexes have been determined. Th e results showed that the formed complexes were Cu(o-MDAP)(2) and Ag(o-MDAP ), respectively. Their true molar absorptivities were equal to epsilon = 7. 79 x 10(4) L mol(-1) cm(-1) at 510 nm and 2.21 x 10(4) L mol(-1) cm(-1), an d their overall stability constants were K = 3.41 x 10(9) and 1.80 x 10(4) respectively. The precision of copper and silver determinations was 2.3% an d 3.1%, respectively.