HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC A NALYSIS OF SULFONAMIDES IN LIVESTOCK PRODUCTS USING MATRIX SOLID-PHASE DISPERSION (MSPD) METHOD WITH SILICA-GEL

The MSPD method with silica gel (Silica Gel-MSPD) was developed for th e extraction of sulfonamides in livestock products. Residual sulfonami des such as sulfameradine (SMR). sulfadimidine (SDD), sulfamonomethoxi ne (SMM), sulfadimethoxine (SDM) and sulfaquinoxarine (SQO) were extra cted from chicken muscle tissue, yolk and pork muscle tissue. A sample (0.5 g) was mixed with 0.7 g of silica gel and 1.5 ml of acetonitrile , and the mixture was dried, washed with hexane and eluted with methan ol or tetrahydrofuran (THF). An aliquot of the methanol or THF solutio n was subjected to HPLC for the determination of each sulfonamide. The recoveries of sulfonamides added to the chicken, yolk and pork were 7 8.1 to 93.1%, 74.6 to 86.2% and 69.6 to 87.1%, respectively. The limit s of detection for the proposed method were 0.01 ppm for SMR and SDD, 0.02 ppm for SMM and 0.04 ppm for SDM and SQO. In order to confirm the utility of the proposed method, analyses of commercial products were performed, and the result was compared with that obtained by MSPD with ODS. Consequently, 0.94 ppm of SMM and 0.99 ppm of SDM were detected in two samples of pork muscle by the proposed method, whereas the valu es detected by using ODS were 0.81 and 0.56 ppm, respectively.