Determination Of Seven Sulfonamides Residues In Poark By Liquid Chromatography-Mass Spectrometry

Sulfonamides(SAs) is a broad-spectrum antobiotic, Because of its toxic properties, it has been banned from producing animal foods in the European community etc. than 0.1mg/kg . Several analytical methods for the determination of SAs in different biological materials, based on gas chromatography , gas chromatography-mass spectrometry, liquid chromatography have been published. But GC and HPLC can not satisfied with analytical requirement because of low sensitivity. GC-MS method has demonstrated excellent sensitivity, but the sample treatment is time-consuming, require derivatization. Therefore, it is necessary to install an effective determination method.The method to determinate sulfonamides, HPLC was compared with LC-APCI-MS. HPLC method ,its detection limit is 20μg/kg, has low sensitivity. while LC-APCI-MS, its detection limit is 4μg/kg, has high sensitivity, can improve greatly stability,accuracy,reproducibility and detection limit. LC conditions and MS parameters are optimized, RSD is 1.3%～9.7%.The effects of different extraction method on rate were studied. The sample was homogenated 2 minutes , and ultrasonic 120s under the condition of 30℃and 700W. The extracted liquid was purified by oasis MCX , elution liquid was optimized, the effects of solid phase extraction on purity were studied. Recoveries were ranged from 59.0% to 124.5% for all compounds at three different spiked levels ,relative standard deviations(RSD) are between 1.4% and 15.4%, and the limits of detections ranged from 3.87 ng/g to 4.21ng/g. The sensitivity of this methods far below the maximum residue limit established by European Commolunity. This method is simple ,accurate and suitable for identification and quantification of sulfonamides in pork tissue.The sulfonamides residual level of 79 pork tissue sample bought from market were determined, results showed that positive rate was 63.29% and ultra-standard rate was 3.80%. pork kidney and pork liver were the most positive or ultra-standard tissue.SM , the highest positive rate sulfonamide of 7 sulfonamides, is 53.16%, followed by SQX and SD, is 11.39% and 10.13%, respectively. All the ultra-standard drug is SM, whose ultra-standard rate is 7.14%. it showed that the pollution of sulfonamides in pork tissue in Luohe urban is serious.