Determination of trace Cd and Pb in environmental and biological samples by ETV-ICP-MS after single-drop microextraction

A method based on single-drop microextraction (SDME) combined with electrothermal vaporization (ETV)-ICP-MS was proposed for the determination of trace Cd and Pb. 8-Hydroxyquinoline (8-HQ) was employed as extractant dissolved in several microliters of chloroform and then an organic microdrop was formed at the tip of the microsyringe needle to extract the interest analytes. The vaporization behavior of the metal-8-HQ chelates in graphite furnace was investigated, and the ETV temperature program was optimized. The factors that influenced the extraction efficiency of target analytes (including pH value, flow rate of sample, extraction time and organic microdrop volume) were studied. Under the optimum conditions, the detection limits of the Cd and Pb were 4.6 and 2.9 pg mL−1 with the enrichment factor of 140-fold for Cd and 190-fold for Pb, respectively. The proposed method was applied successfully to the determination of trace Cd and Pb in environmental and biological samples. In order to validate the developed method, a certified reference material of GBW 08501 peach leaves was analyzed and the determined values obtained were in a good agreement with the certified values.