DETERMINATION OF CHLORFLUAZURON IN FEED B Y HPLC

An analytical method for chlorfluazuron (CFA) in feed by HPLC was esta blished. Water was added to a sample, and CFA was extracted with aceto nitrile. The extract was cleaned up on a porous diatomite cartridge, f ollowed by a Florisil column and a silica cartridge. The CFA was deter mined by HPLC on an ODS column of Mightysil RP18 (4.6 mm i.d. x 250 mm ) with a UV detector (260 nm). The recovery test was conducted with 3 kinds of feed spiked with CFA at levels of 0.02 similar to 2.0 ppm. Th e mean recovery values were in the range of 78.7 similar to 95.7%, and the relative standard deviations of repeatability (RSDr) were within 14.1%. A collaborative study (7 laboratories) was conducted with mixed feed spiked with CFA at the level of 1.0 ppm. The mean recovery was 8 7.7%, and the relative standard deviation of reproducibility (RSDR) wa s 3.7%. The detection limit was 0.02 ppm in a sample.