PACKED-COLUMN GAS-CHROMATOGRAPHIC METHOD FOR THE SIMULTANEOUS DETERMINATION OF 10 PYRETHROID INSECTICIDE RESIDUES IN FRUITS, VEGETABLES, AND GRAINS

A simple, rapid, packed-column gas chromatographic method was developed for simultaneous determination of 10 pyrethroid insecticide residues (allethrin, biphenthrin, cyhalothrin, permethrin, cyfluthrin, flucythrinate, fenvalerate, fluvalinate, deltamethrin, and py-115) in fruits, vegetables, and grains. These multiresidues are extracted from various crops with acetone-petroleum ether and cleaned up on a Florisil column (for the fruits and vegetables) or on a Florisil-charcoal-alumina column (for the grains) prior to their determination by gas chromatography with an electron capture detector. Recoveries of 10 pyrethroid compounds from 12 different crops (maize, soybeans, wheat, sorghums, paddy, potatoes, cucumbers, cauliflowers, spinaches, apples, bananas, and oranges) fortified at levels of 0.02-5.00 ppm ranged from 58 to 130%. In a separate precision study, coefficients of variation were 5.5-14.6% at 0.1-0.5 ppm (n = 10, maize), and 4.1-12.1% at 0.010-0.050 ppm (n = 10, apples). The detection limits of the method ranged from 2.0 to 10.0 ppb on a crop basis.