Simple and rapid determination of sulfonamides in milk using Ether-type column liquid chromatography

A simplified and rapid determining/identifying method for residual sulfonamides (SAs) in milk by using Ether-type stationary phase, which made in our lab, was presented. The target analytes were extracted by mixing with ethanol-acetic acid (97:3, v/v) followed by centrifugation. The procedure used a Ether-type C8 column, isocratic elution with acetonitrile-water (5:95, v/v), and a photo-diode array detector. The linear range of determination was 50-10,000mug/L for sulfanilamide and 100-10,000mug/L for sulfadiazine, sulfamerazine, sulfamethazine. Average recoveries of four SAs (spiked 0.5, 1.0 and 1.5mug/mL) ranged from 80.1% to 87.6%, with relative standard deviations between 3.4% and 5.8%. The total time and solvent required for the analysis of one sample were <15min and <1.0mL of ethanol and 0.6mL of acetonitrile, respectively. The developed procedure was nearly harmless to the human and environment.