DETECTION OF SULFAMETHAZINE RESIDUES IN MILK BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple high performance liquid chromatographic (HPLC) procedure for the detection of sulfamethazine residues in milk is described. Milk is extracted with chloroform, the extract evaporated to dryness and the redissolved in potassium phosphate buffer (pH 5.0). The chloroform extract, in buffer, is passed through a cyclobond I solid phase extraction (SPE) column. The SPE column is washed with 10 ml potassium phosphate buffer and then sulfamethazine is eluted with 2 ml aqueous (50%) methanol. The eluent is directly analyzed by HPLC with uv detection at 265 nm. The recoveries ranged from 83.2% to 88.2% in samples fortified between 5 to 40 ppb levels.