In Situ Solvent Formation Microextraction in the Presence of Ionic Liquid for Preconcentration and Speciation of Arsenic in Saline Samples and Total Arsenic in Biological Samples by Electrothermal Atomic Absorption Spectrometry

摘要

In this modality, the extraction phase is formed in situ while simultaneously extracting analytes. First, a water-miscible ionic liquid (IL) ([Hmim][BF₄]), capable of complete dissolving in the aqueous solution, was added to the sample. Then, an ion-exchange reagent (NaPF₆) was added to obtain the hydrophobic IL ([Hmim][PF₆]) that acted as the analyte extractant to form the cloudy homogeneous solution for the preconcentration and speciation of trace amounts of As (III) and As (V) with electrothermal atomic absorption spectrometry (ETAAS) detection. In situ solvent formation microextraction is a simple and rapid method for extraction and preconcentration of metal ions from sample solutions containing high concentration of salt. Some effective factors that influence the microextraction efficiency were investigated and optimized. Under the optimum experimental conditions, the limit of detection (3 σ) and the enrichment factor were 6 ng L-1 and 198, respectively. The obtained relative standard deviation was 4.78%. The proposed method was successfully applied for the determination of As (III) and As (V) in water samples, food salts, and total As in biological samples.