Determination of antibacterial reagents by liquid chromatography-electrospray-mass spectrometry

This paper describes a newly developed liquid chromatography-electrospray-mass spectrometry (HPLC-ES-MS) method for the determination of 13 antibacterial reagents (olaquindox, trimethoprim, clopidol, ormethoprim, morantel, carbadox, thiamphenicol, pyrimethamine, furazolidone, oxolinic acid, difurazon, nalidixic acid, piromidic acid). The optimization for the detection of these compounds by HPLC-ES-MS was investigated. A C(18) column with gradient elution was utilized for the separation of thirteen antibacterial chemicals. Collision induced dissociation (CID) was used to induce fragmentation of analyte molecules and enhance the specificity of the method. Selective ion monitoring (SIM) was employed for quantitative determination. The detection limit of this method proved to be much better than previously reported ones. Satisfactory linearity, 0.5-10 ppm, of each compound was obtained. A solvent extraction method to extract analyte compound from pork was developed. The application of this newly developed method was demonstrated by analyzing antibacterial reagent added pork samples.