Analysis of the Dithiocarbamate Fungicides Ziram, Maneb, and Zineb and the Flotation Agent Ethylxanthogenate by Ion-Pair Reversed-Phase HPLC

Although large quantities of dithiocarbamate fungicides and ethylxanthogenate mineral flotation agents are released routinely to the environment, little is known about their fate and effects because sensitive analytical techniques are not available. A simple and selective HPLC method for trace level analysis of dithiocarbamate fungicides and xanthogenates (dithiocarbonates) in natural waters has been developed. The method is based on the in situ formation of a 1:1 Cu(II)−dithioligand complex and its separation as an ion pair with hexanesulfonate on a C-18 reversed-phase column. The compounds are detected at the wavelength of maximum absorption of the Cu(II)−ligand complex (260−287 nm). Method detection limits are 20 nM dimethyldithiocarbamate (i.e., 3 μg/L Ziram), 33 nM ethylenebis(dithiocarbamate) (i.e., 9 μg/L Maneb), and 23 nM ethylxanthogenate (i.e., 4 μg/L). An on-line preconcentration step can be used to lower the detection limits by a factor of 5−10.