Simultaneous detection of zinc dimethyldithiocarbamate and zinc ethylenebisdithiocarbamate in cabbage leaves by capillary electrophoresis with inductively coupled plasma mass spectrometry.

We report a simple and highly sensitive method for the simultaneous detection of trace zinc dimethyldithiocarbamate and zinc ethylenebisdithiocarbamate by capillary electrophoresis with inductively coupled plasma mass spectrometry. Zinc dimethyldithiocarbamate and zinc ethylenebisdithiocarbamate were chelated with trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid to form a macromolecule complex. Then, these two compounds were separated by α-cyclodextrin-modified capillary electrophoresis within 12 min at a separation voltage of 15 kV and measured by inductively coupled plasma mass spectrometry. The developed method is sensitive with detection limit of 1.9 and 3.0 ng Zn/mL for zinc dimethyldithiocarbamate and zinc ethylenebisdithiocarbamate, respectively. By means of ultrasound-assisted extraction methods, zinc dimethyldithiocarbamate and zinc ethylenebisdithiocarbamate spiked into cabbage leaves were successfully extracted and determined with a relative standard deviation (n = 5) ≤ 6% and a recovery of 95-107%.