Determination of trace vancomycin in edible animal tissues and assessment of matrix effects

Vancomycin (VCM) is known as the last line of defense against gram-positive bacteria. For one health, the rapid and effective monitoring of VCM is very important. In this study, a new liquid chromatography-tandem mass spectrometry method was established to detect VCM residues in livestock, poultry and fish. Tissues samples were extracted with 40% acetonitrile and 0.1% formic acid solution, and purified with the surface molecularly imprinted solid-phase extraction. The results showed that the method had good linearity (r > 0.99) in the range of 1–100 ng/mL, and the average recoveries of VCM in ten edible tissues at 1, 2 and 10 μg/kg spiking levels were 93.2–117%, with the relative standard deviations below 12.1%. The limits of detection and quantification were 0.5 and 1 μg/kg, respectively. Compared to conventional cartridges, the new cartridge could more effectively remove phospholipids in tissues samples. Furthermore, the statistical analysis demonstrated that there was a significant difference between the slopes of matrix-matched calibration curves of before and after purification (p < 0.05). The endogenous lysophosphatidylcholine proved to be a main effector that caused strong matrix inhibitory effect on VCM analysis.