Quantification of Metal Dithiocarbamates by Thin-Layer Chromatography

A chromatographic method for the determination of metal dithiocarbamates: antimonic(III) dipentyldithiocarbamate (Sb-5-DTC), zinc dipentyldithiocarbamate (Zn-5-DTC), zinc dibutyldithiocarbamate (Zn-4-DTC), ferric(III) dipentyldithiocarbamate (Fe-5-DTC), and lead(II) dipentyldithiocarbamate (Pb-5-DTC) was developed. Separations were performed on thin-layer chromatography (TLC) RP-18 silica gel with a propan-2-ol and water mixture (10: 1, v/v) as the mobile phase. The chromatographed compounds were detected using the iodine-azide detection procedure. Plates were sprayed with a mixture of sodium azide (2%), potassium iodide (0.01 mol L-1), and starch solution (1%) adjusted to pH 6.0 and exposed to iodine vapor for 15 s. The compounds were visible as white spots against a violet background which were converted into chromatograms using TLSee software. The linear functions of concentration for Sb-5-DTC, Zn-5-DTC, Zn-4-DTC, Fe-5-DTC, and Pb-5-DTC were in the ranges of 100-2000, 50-1000, 50-1000, 50-1000, and 100-3000 pmol per spot, respectively. The limits of detection and quantification were at a level of tens of pmol per spot.