Derivative spectrophotometric method for copper determination.

A simple, sensitive and selective method by solvent extraction-first derivative spectrophotometry is described for the determination of microamounts of copper in water by means of its reaction and extraction at pH 8.0 with 3-(4-phenyl-2-pyridinyl-5-phenyl-1,2,4-triazine) (PPT) and picrate (2,4,6-trinitro-phenol) into 1,2-dichloroethane. Copper was thus determined in the range 7.5-350 ng/ml with a detection limits (3σ) of 2.3 ng/ml. The relative standard deviations were in all instances less than 2.0%. The proposed method was successfully applied for the determination of copper in several kinds of water.