Magnetic solid-phase extraction with dispersion of magnetic hypercrosslinked polystyrene with carbon dioxide for multicomponent extraction of residues of 55 veterinary drugs from river waters before their determination by HPLC-MS/MS

Magnetic effervescent tablets consisting of magnetic hypercrosslinked polystyrene, sodium bicarbonate, citric acid and EDTA are proposed for multicomponent isolation of residues of 55 veterinary drugs of different classes (sulfonamides and trimethoprim, amphenicols, nitroimidazoles, β-lactams, quinolones, macrolides, pleuromutilins and lincosamides) from river waters by magnetic solid-phase extraction before their HPLC-MS/MS determination. Due to the intensive release of carbon dioxide during dissolution of the tablet it is possible to do without the use of stirring devices, and the magnetic properties of the sorbent allow its separation without centrifugation and filtration; as a result, the sample preparation procedure (solid-phase extraction) takes less than 3 min. The method provides relative recoveries from 79 to 122 % and good reproducibility (sr ≤ 0.12). Medicine substances were identified by the exact masses of analyte ions produced by electrospray ionisation with polarity switching. The matrix effect for all drugs is below 20 %. Determination was carried out by matrix calibration method and the limits of detection and quantification were 0.012 and 0.04 µg/L for most of the sulfonamides, trimethoprim, amfenicols, nitroimidazoles, macrolides, pleuromutilins and lincosamides and 0.06 and 0.2 µg/L for β-lactams and quinolones respectively.