Residues of benomyl (determined as carbendazim) and captan in postharvest-treated pears in cold storage

Residues of carbendazim (applied as benomyl) and captan, applied to pears prior to cold storage, were examined during 6 months of storage. Total carbendazim residues were below the 7 ppm tolerance, initial residues averaging 0.37 ppm, and no reduction of residues was detected during cold storage. In another study, three postharvest application techniques were compared and again no significant differences in the quantities of the residues found. Captan residues on Anjou pears were insignificant. The analytical procedure used for these analyses was an acetone extraction of acidified pear puree followed by partitioning with ethyl acetate to separate total carbendazim (benomyl plus carbendazim) and captan residues. For captan residue, charcoal and silica gel cleanup of the organic extract was followed by electron capture GLC. The pH of the aqueous extract containing carbendazim was adjusted to about 9 with sodium hydroxide, and the carbendazim residue was partitioned into ethyl acetate and analyzed by HPLC.