Ultra-Trace Determination of Copper and Silver in Environmental Samples by Using Ionic Liquid-Based Single Drop Microextraction-Electrothermal Atomic Absorption Spectrometry

Abstract

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