Simultaneous Determination of 45 Antibiotic Drugs in Temporary Aquaculture Water by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry with Automatic Solid Phase Extraction

A method for simultaneous determination of 45 antibiotic drugs in temporary aquaculture water, including 4 tetracyclines, 3 chloramphenicols, 15 quinolones, 17 sulfonamides, 4 furanes, malachite green and leucomalachite green, was proposed by ultra-high performance liquid chromatography tandem mass spectrometry with automatic solid phase extraction. 40.0 mL of temporary aquaculture water was taken and mixed well with 10 mL of Na₂EDTA-Mcllvaine buffer solution. The mixed internal standard (0.05 mL) was added, with 1.00 mg·L^-1 of deuterated quinolones and sulfonamides, and 100 μg·L^-1 of deuterated malachite green, leucomalachite green and chloramphenicols. The above solution was adjusted to pH 4 with 0.1 mol·L^-1 hydrochloric acid solution, and the solution was passed through HLB solid phase extraction column, which was pre-activated with 3 mL of methanol and 3 mL of water. Elution was carried out with 6 mL of methanol after rinsing with 2 mL of water, and the eluate was collected and blown to near dryness by nitrogen at 40℃. The residue was reconstituted in 1.00 mL of 20% (volume fraction) methanol solution, and the solution was passed through 0.2 μm filter membrane. The filtrate was separated on Agilent Eclipse Plus C₁₈ RRHD column, with the mixtures of methanol and 0.1% (volume fraction) formic acid solution at different volume ratios as the mobile phase for gradient elution, and multiple reaction monitoring (MRM) mode for the qualitative and quantitative analysis. As shown by the results, linear range of working curves for chloramphenicols and malachite green was 0.200-20.0 μg·L^-1, with lower limits of determination of 5.0 ng·L^-1, while linear range of working curves for other antibiotic drugs was 1.00-100 μg·L^-1, with lower limits of determination of 25 ng·L^-1. Test for recovery was made by standard addition method, giving results in the range of 61.6%-115%, with RSDs (n=6) of the determined values less than 9.0%.