A HPLC Screening Procedure for Sulfamethazine Residues in Pork Tissues

Abstract

A sensitive and specific screening procedure is described for the quantitative detection of sulfamethazine residues in pork kidney, liver and muscle. Initial screening is by both the Bratton-Marshall reaction, and by high pressure liquid chromatography (HPLC); quantitation is by HPLC; identification is then confirmed by means of thin-layer chromatography (TLC) of the derivatized standards and the unknown from the Bratton-Marshall reaction. Only one extraction of a 50g sample is needed, one portion (10g tissue equivalent) is used for the colorimetric reaction and TLC confirmation, and another portion (25g tissue equivalent) is used for quantitative HPLC determination. Standard curves for sulfamethazine are constructed for each tissue at 50, 100, 200 and 500 ppb levels. The average mean recovery for all tissues at all levels is 78.2%. The method is verified by a 150 sample survey using 50 samples of each tissue from local supermarkets. Approximately 4% of the samples show contamination ranging from a level of 100 ppb to 3 ppm.