Gas-liquid chromatographic determination of thiabendazole and methyl 2-benzimidazole carbamate in fruits and crops.
A method is described for the electron capture gas-liquid chromatographic determination of thiabendazole and methyl 2-benzimidazole carbamate (MBC) after derivatization with pentafluorobenzyl bromide (PFB-Br). The samples are extracted with ethyl acetate, and the residual thiabendazole, benomyl, and MBC are isolated by liquid-liquid extraction into dilute HCl. After neutralization and re-extraction with ethyl acetate, thiabendazole and MBC are reacted with PFB-Br to form the PFB derivatives. Alumina column chromatography was used to clean up extracts, and the derivatives could be detected as low as 5-10 pg. Recoveries were 95-98% from fruits fortified with 0.3-2.0 ppm thiabenzadole; recoveries were 91-97% when 0.05-1.0 ppm benomyl/MBC were added to fruits/crops. The PFB derivatives were identified by gas-liquid chromatography-mass spectrometry.
D001562:Benzimidazoles / Q000032:analysis*; D002219:Carbamates / Q000032:analysis*; D002849:Chromatography, Gas; D005638:Fruit / Q000032:analysis*; D005659:Fungicides, Industrial / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D010573:Pesticide Residues / Q000032:analysis; D013827:Thiabendazole / Q000032:analysis*; D014675:Vegetables / Q000032:analysis*
D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; D010573:Pesticide Residues; D013827:Thiabendazole