UHPLC-MS/MS Determination of Varieties of Veterinary Drug Residues in Aquatic Products with Solid Phase Extraction

Mixture of acetonitrile and ethyl acetate(3+2) (15.0 mL) was used as solvent in the ultrasonic assisted extraction of varieties of veterinary drug residues attributed to categories of quinolones (QNL′s) and sulfonamides (SFM′s) in sample (3.00 g) of aquatic products. After centrifugation, 10.00 mL of the supernatant were taken for separation using amino-based SPE column. The column was rinsed with n-hexane and acetonitrile in succession to remove fats and interfering substances, and then eluted successivly with methanol and mixture of CH3OH and CH3COOH (99+1), the eluate was collected and evaporated to dryness at 45 ℃. The residue was taken up with 1 mL of a mixture of acetonitrile and 5 mmol·L-1 NH4OAc solution (which contains 0.1% by vol. of formic acid), mixed in the ratio of 1 to 4. The solution was used for LC-MS analysis. 8 drug standards were used as internal standards in the quantification of 14 drugs attributed to QNL′s and SFM′s. Linearity ranges for these drugs were found in the same range within 30 μg·kg-1, with detection limits (3S/N) same as 1 μg·kg-1. Recovery was tested by standard addition method using 2 aquatic product samples as matrixes, results of recovery in the range of 81.2%-116%, and values of RSD′s (n=6) found were ranged from 0.72% to 9.8%.