Dispersive Liquid-Liquid Microextraction of Silver Ion in Food Samples and Determination by Using Flame Atomic Spectroscopy

In this work, a procedure for preconcentration of silver using dispersive liquid–liquid microextraction with the reagent dithizone as complexing reagent was developed. At pH 2, silver ions are complexed with dithizone and extracted into the fine droplets formed when mixing carbon tetrachloride (extraction solvent), ethanol (disperser solvent) and the sample solution. After extraction, the phases are separated by centrifugation and silver is determined in the enriched phase by FAAS. After extraction, the enrichment factor was 73.21. The detection limit of the method was 30.4 ng mL and the relative standard deviation for ten determinations of 0.1 μg mL-1 silver was 3.19 %. The results for the determination of silver in environmental water samples (tap water, well water, mineral water), tea and pepperbush have demonstrated the applicability of the proposed method.