Solidified floating organic drop microextraction combined with ETV-ICP-MS for the determination of trace heavy metals in environmental water samples

A new method of solidified floating organic drop microextraction (SFODME) combined with electrothermal vaporization (ETV)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of trace heavy metals in environmental water samples with sodium diethyldithiocarbamate (DDTC) as both chelating reagent in SFODME and chemical modifier in ETV. The factors affecting the microextraction efficiency were studied in detail and the optimal extraction conditions were established. Under the optimal conditions, the limits of detection (LODs) for SFODME-ETV-ICP-MS determination of Co, Pd, Cd, Hg, Pb and Bi were found to be 0.0060, 0.0091, 0.0020, 0.0041, 0.0170 and 0.0041 ng mL(-1), respectively, with the relative standard deviations (RSDs) of 2.8-10.0% (c=0.5 ng mL(-1), n=7). The developed method was successfully applied to the analysis of six target metals in Yangtze River and East Lake water samples with recoveries ranging from 77.7 to 119.1%. To validate the accuracy of the method, a certified reference material of Environmental Water (GSBZ50009-88) was analyzed and the determined values were in good agreement with the certified values.