Deep eutectic liquid organic salt as a new solvent for liquid-phase microextraction and its application in ligandless extraction and pre-concentraion of lead and cadmium in edible oils

Deep eutectic liquid organic salt was used as the solvent and a liquid phase microextraction (DES-LPME) combined with electrothermal atomic absorption spectrometry (ETAAS) was developed for separation, preconcentration and determination of lead and cadmium in edible oils. A 4:1 mixture of deep eutectic solvent and 2% nitric acid (200 mu L) was added to an oil sample. The mixture was vortexed and transferred into a water bath at 50 degrees C and stirred for 5 minutes. After the extraction was completed, the phases were separated by centrifugation, and the enriched analytes in the deep eutectic solvent phase were determined by ETAAS. Under optimized extraction conditions and for an oil sample of 28 g, enhancement factors of 198 and 195 and limits of detection (defined as 3 S-b/m) of 8 and 0.2 ng kg(-1) were achieved for lead and cadmium respectively. The method was successfully applied to the determination of lead and cadmium in various edible oils. (C) 2015 Published by Elsevier B.V.