Determination of colistin sulfate, bacitracin and Virginiamycin M1 residues in aquatic products by HPLC-MS/MS

A high performance liquid chromatography tandem mass spectrometric (HPLC-MS/MS) method was established to simultaneously detect colistin sulfuric (CS), bacitracin (BTC) and virginiamycin M1 (VGMM1) in aquatic products. We extracted the samples with methanol- 0.1% formicacid(V:V=2:5), removed their protein with 4% TCA acetonitril, removed fat with acetonitrile saturated n-hexane, and then cleaned them up with OASiS HLB solid phase extraction (SPE) column. Next, we detected the analytes by HPLC-MS/MS under the selected reaction monitoring mode and quantified them by external standard method. Results show that CS and BTC have good linearity between the peak areas in concentrations ranged 0.01~10.00 mgL-1, VGMM1 as well in concentrations ranged 0.002~2.000 mgL-1, and the correlation coefficients (R2) are all more than 0.995. The detection limits of CS, BTC and VGMM1 are 10 gkg-1, 10 gkg-1and 2 gkg-1 respectively, and the quantification limits are 20 gkg-1, 20 gkg-1 and 4 gkg-1respectively. Three samples in three different concentration levels are chosen for recovery, getting a 72.3%~103.9% average recovery rate, and a relative standard deviations varying from 1.10%~10.92%. In conclusion, method proposed has advantages of simplicity, sensitivity and repeatability, which providetechnicalsupport for the detection of these 3 kinds of drug residues in aquatic products.