LIQUID-CHROMATOGRAPHIC DETERMINATION OF SIMAZINE, ATRAZINE, AND PROPAZINE RESIDUES IN CATFISH

A liquid chromatographic (LC) method is described for the simultaneous determination of the triazine herbicides, simazine (SIM), atrazine (A TZ), and propazine (PRO) in the 12.5-100 ppb range in catfish. The her bicides are extracted from catfish homogenates with ethyl acetate, fol lowed by solvent partitioning between acetonitrile and petroleum ether and additional cleanup on a C-18 cartridge. A Supelcosil LC-18-DB col umn is used for LC separation, and UV determination is at 220 nm. The isocratic mobile phase is a mixture of methanol, acetonitrile, and wat er. Mean recoveries from catfish were 88.7, 96.9, and 91.7%; standard deviations were 6.84, 7.78, and 6.26%; and coefficients of variation w ere 7.72, 8.03, and 6.82% for SIM, ATZ, and PRO, respectively.