LIQUID-CHROMATOGRAPHIC ANALYSIS OF THIAMPHENICOL RESIDUES IN MILK

The present paper describes a modified high-performance liquid chromat ographic (HPLC) method for the determination of thiamphenicol (THA) re sidues in spiked milk at levels as low as 30 ppb. Milk spiked with THA was extracted with ethyl acetate. Following addition of hexane, the e xtract was cleaned up with a silica cartridge. Analysis was performed on a reversed-phase C-18, 5 mu m, column using water-methanol (70:30) as mobile phase. Recovery was found to range from 68.0 to 90.0 % and p recision data suggested that relative standard deviation ranged from 7 to 9.4 %.