STUDY ON THE COLOUR REACTION OF COPPER(II ) WITH A NEW CHROMOGENIC REAGENT N-HEPTYL-N' -(SODIUM P-AMINO-BENZENSULFONATE) THIOUREA AND ITS APPLICATION

摘要

A new Chromogenic reagent N- heptyl- N' - ( sodium p - aminobenzensulfonate) thiourea (HPT) [1] was synthesized after the synthesis of N- allyl-N' - (sodium p - aminobenzensulfonate) thiourea (ASATu) [2]. For spectrophotometric determination of copper has been developed and the optimum condition for the colour reaction was studied in detail. In HAc - NaAc buffer solution at pH4. 5-6. 0, HPT reacts with Cu (II ) to form a blue 1:3 complex, HPT and copper-HPT exhibits an absorption maximum at 246.4 nm and 347.6 nm(△ λ = 101.2 nm). respectively. The apparent molar absorptivity is 4.51 × 10~4 L · mol~(-1) ? cm~(-1). Beer's law is obeyed in the concentration range of 5-90μg/25mL Cu( II ) . Using the masking agents, the colour reaction is free from interference by more than thirty ions investigated. Contrasted with some former methods for determination of copper[3,4], the proposed method is simple, rapid, sensitive, selective and unecessary to extract. It has been applied to the spectrophotometric determination of trace amounts of copper in human hair, milk podwer and pig liver with satisfactory results and recovery.