ultra-trace determination of copper and silver in environmental samples by using ionic liquid-based single drop microextraction-electrothermal atomic absorption spectrometry

A sensitive, selective and effective ionic liquid-based single drop microextraction technique was
developed by using ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate, C6MIMPF6, coupled
with electrothermal atomic absorption spectrometry (ETAAS) for the determination of copper and silver in
environmental samples. Dithizone was used as chelating agent. Several factors that influence the
microextraction efficiency and ETAAS signal, such as pH, dithizone concentration, extraction time, amounts of
ionic liquid, stirring rate, pyrolysis and atomization temperature were investigated and the microextraction
conditions were established. In the optimum experimental conditions, the detection limits (3 s) of the method
were 4 and 8 ng L-1 and corresponding relative standard deviations (0.1 μg L-1, n = 6) were 4.2% and 4.8% for
Ag and Cu, respectively. The developed method was validated by analysis of a certified reference material and
applied to the determination of silver and copper.