| Summary |
A high-performance liquid chromatographic (HPLC) method for simultaneous determination of the residue of 2, 4-diaminopyrimidine drugs, including trimethoprim (TMP), ormetoprim (OMP), and pyrimethamine (PYM) in eggs was developed. Samples were extracted with acetonitrile, centrifuged, partitioned with n-hexane, concentrated by rotary evaporation to dryness, and then analysed by HPLC. The conditions were established on a µ-Bondapak C18 column with 5 X 10-3 M acetic acid buffer/ methanol as mobile phase and detected at UV 230 nm. The average recoveries of the three drugs spiked into samples at the levels of 0.5, 1.0, and 2.0 µg / g were 76.5 % to 99.6 %. The lowest detection limit of residual drugs were 0.02 µg /gin eggs. 300 samples from layer farms in Taiwan area were surveyed by random for the residues ofTMP, OMP, and PYM with the developed method. The result indicated that all samples were examined to be below the detection limit of the three drugs.
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