Determination of trace amounts of copper with extraction–photoacoustic spectrometry

Abstract

A sensitive method for the determination of copper in aqueous solution by pulsed laser-induced photoacoustic spectrometry after extraction is described. The copper is chelated with 1,5-diphenylcarbazide in chloroform and extracted into the chloroform phase. The optimum extraction conditions were found experimentally. By using the stepwise dilution method, the minimum absorbance that could be measured was 8.5 × 10^–6 at 6.2 mJ per pulse; this corresponds to 6.9 × 10^–3µg l^–1 of copper in chloroform. The relative standard deviation for ten measurements of an absorbance of 7.8 × 10^–3 at 0.7 mJ is 1.5%. Application of the method to the determination of copper in biological samples is also described. The results obtained were compared with those given by atomic absorption spectrometry.