The use of 1-[pyridyl-(2)-azo]-naphthol-(2) in the presence of TX-100 and N, N′-diphenylbenzamidine for the spectrophotometric determination of copper in real samples

Abstract

A simple and sensitive field detection and spectrophotometric method for determination of copper described herewith is based on the formation of a red coloured species of copper(II) with 1-[pyridyl-(2)-azo]-naphthol-(2) (PAN), TX-100 and N, N′-diphenylbenzamidine (DPBA) at pH range 7.8–9.4. The red coloured Cu(II)-PAN-(TX-100)-DPBA complex in chloroform shows maximum absorbance at 520 nm with molar absorptivity value of 1.14×10 5 l mol −1 cm −1. The detection limit of the method is 2 ng ml −1 organic phase. The system obeys Beer’s law up to 0.6 μg Cu(II) ml −1 in organic solution. Most of the common metal ions generally found associated with copper do not interfere. The repeatability of the method was checked by finding relative standard deviation (RSD) ( n=10) value for solutions each containing 0.2 μg ml −1 of Cu(II) and the RSD value of the method was found to be 1.5%. The validity of the method has been satisfactorily examined for the determination of copper in soil and airborne dust particulate samples.