High performance liquid chromatographic method for simultaneous determination of residual benomyl and methyl 2-benzimidazole carbamate on apple foliage without cleanup.
A simple HPLC method has been developed to individually determine residues of benomyl and MBC on apple leaves without cleanup. Sample leaves in a Mason jar are freeze-dried and tumbled for extraction in CHCl3 containing 5000 microgram n-propyl isocyanate/mL at 1 degree C. n-Butyl isocyanate is added to the extract of 5000 microgram/mL, and 20 microL of the mixture is injected into the HPLC system. A brownlee LiChrosorb silica gel column with a guard column is operated with a mixed mobile phase of chloroform--hexane (4 + 1) saturated with water. MBC, present as a degradation compound of benomyl, is identified as methyl 1 - (n - propylcarbamoyl) - 2 - benzimidazole carbamate (MBC-n-PIC derivative). At 280 nm, both benomyl and MBC-n-PIC can be detected with a UV detector at a level of 0.2 ppm in apple leaves.
D001542:Benomyl / Q000032:analysis*; D001562:Benzimidazoles / Q000032:analysis*; D002219:Carbamates / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005638:Fruit / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*
D001562:Benzimidazoles; D002219:Carbamates; D010573:Pesticide Residues; C006698:carbendazim; D001542:Benomyl