ANALYSIS OF METRIBUZIN AND ASSOCIATED METABOLITES IN SOIL AND WAVER SAMPLES BY SOLID PHASE EXTRACTION AND REVERSED PHASE THIN LAYER CHROMATOGRAPHY

摘要

A method to analyze metribuzin, 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one, and its major metabolites, deaminated metribuzin, DA, 6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one, diketometribuzin, DK, 4-amino-6-(1,1-dimethylethyl)-1,2,4-triazin-3,5(2H,4H) -dione and deaminated diketometribuzin, DADK, 6-(1,1-dimethylethyl)-1,2,4-triazin-3,5(2H,4H)-dione in soil and water samples by reversed-phase thin layer chromatography (RPTLC) is described. Soil samples were extracted with MeOH:0.01 M CaCl2.2H(2)O (4:1) and the extracts filtered to remove the sediment. The extract then was diluted with deionized water and eluted through a C18, solid phase extraction (SPE) cartridge. Water samples (150-mL) were eluted directly through C18, SPE cartridges. Both soil and water extracts were chromatographed on pre-coated RPTLC plates. The concentration of metribuzin was determined by UV densitometry at 290 nm. Recoveries of metribuzin from soil samples fortified at 2 mg kg(-1) ranged from 73-86%. Recoveries from water samples fortified at 10 and 100 mu g L(-1) ranged from 85 to 92%. The detection limit of the method for metribuzin is 30 nanograms.