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

A simple and sensitive field detection and spectrophotometric method for de termination 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 c oloured Cu(II)-PAN-(TX-100)-DPBA complex in chloroform shows maximum absorb ance at 520 nm with molar absorptivity value of 1.14 x 10(5) l mol(-1) cm(- 1). The detection limit of the method is 2 ng ml(-1) organic phase. The sys tem obeys Beer's law up to 0.6 mu g Cu(II) ml(-1) in organic solution. Most of the common metal ions generally found associated with copper do not int erfere. The repeatability of the method was checked by finding relative sta ndard deviation (RSD) (n = 10) value for solutions each containing 0.2 mu g 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 determinat ion of copper in soil and airborne dust particulate samples. (C) 1999 Elsev ier Science B.V. All rights reserved.