Single-Drop Microextraction Combined with Low-Temperature Electrothermal Vaporization ICPMS for the Determination of Trace Be, Co, Pd, and Cd in Biological Samples

A new method of single-drop microextraction combined with low-temperature electrothermal vaporization (LTETV)-ICPMS was proposed for the determination of trace Be, Co, Pd, and Cd with benzoylacetone (BZA) as both extractant and chemical modifier. Several factors that influence the microextraction efficiency, such as sample flow rate, microdrop volume, and extraction time, were investigated and the optimized microextraction conditions were established. Be, Co, Pd, and Cd in the postextraction organic phase were directly determined by LTETV-ICPMS with the use of BZA as chemical modifier. The chemical modification of BZA in LTETV-ICPMS was studied, and the factors affecting the formation of chelates and vaporization/transportation of chelates were investigated. Under the optimized conditions, the detection limits of the method were 0.12, 0.99, 1.5, and 0.27 pg/mL for Be, Co, Pd, and Cd, and the relative standard deviations for 0.1 ng/mL Be, Co, Pd, and Cd were 16, 14, 14, and 11%, respectively. After 10 min of extraction, the enrichment factors were 160 (Be), 125 (Co), 40 (Pd), and 180 (Cd). The proposed method was applied to the determination of trace Be, Co, Pd, and Cd in biological reference materials, and the determined values were in good agreement with the certified values.