Cloud point extraction of trace cyanide from environmental waters for indirect flame atomic absorption spectrometric determination

Abstract

A method has been developed for indirect determination of cyanide in environmental waters based on cloud point extraction (CPE), preconcentration and determination by flame atomic absorption spectrometry (FAAS). The method was based on reduction of Cu(II) to Cu(I) in the presence of cyanide and complexation of the produced Cu(I)(CN)₂⁻ with gallocyanin (GC⁺) as an ion-pairing reagent at pH 4.0, followed by its extraction into polyethyleneglycol mono-p-nonylphenylether (Ponpe 7.5). Selectivity was improved with the use of suitable masking agents. Various factors influencing separation and preconcentration of cyanide have been investigated, and conditions were optimized, allowing determination of cyanide in the range of up to 1.2 mg L⁻¹ with a detection limit of 0.00045 mg L⁻¹. The method has been applied to the determination of cyanide in environmental waters, the results being in agreement with those obtained by a reference method.

Keywords:

• cyanide
• gallocyanin
• environmental waters
• ion-associate complex
• cloud point extraction
• flame atomic absorption spectrometry

Acknowledgments

The present study was performed as a part of the project number F-365 financed by the Scientific Research Projects Fund of Cumhuriyet University, CÜBAP. The authors are grateful to Dr Mehmet Akçay for linguistic preparation and scientific contributions to the manuscript.