Determination of Sulfonamides and Quinolones Antibiotics Residues in Water Samples by High Performance Liquid Chromatography£­Tandem Mass Spectrometry with Mixed Adsorbents Based Magnetic Solid Phase Extraction

KeyWord:mixed magnetic adsorbents  magnetic solid phase extraction£¨MSPE£©  high performance liquid chromatography£­tandem mass spectrometry£¨HPLC£­MS/MS£©  antibiotics residues

Abstract:

      A magnetic macroporous material£¨Fe3O4@SiO2@PLS£© and a metal organic framework composite£¨Fe3O4@ZIF£­8£© were synthesized in this paper£¬and they both were combined to use as a mixed magnetic adsorbent£®Based on this£¬a high performance liquid chromatography£­tandem mass spectrometry?£¨HPLC£­MS/MS£© with the mixed magnetic adsorbent solid phase extraction£¨MSPE£© was established for the quantitative analysis of 4 sulfonamides and 8 quinolones in water samples£®The morphologies£¬chemical structure information and crystalline structures of the prepared materials were characterized by scanning electron microscopy£¨SEM£©£¬Fourier£­transform infrared spectroscopy£¨FT£­IR£© and X-ray diffractometry£¨XRD£©£®The results showed that the prepared Fe3O4@SiO2@PLS appeared nearly spherical in shape£¬with a large specific surface and an average size of 500£­600 nm£¬nearly without Fe3O4 on the surface£¬suggesting the formation of core£­shell structure Fe3O4@SiO2@PLS£¬while Fe3O4@ZIF£­8 was nearly spherical in shape£¬with an average diameter about 200 nm and a rough surface£®The crystalline structures of Fe3O4 and ZIF£­8 in Fe3O4@ZIF£­8 did not change after the preparation reaction£¬indicating that the spherical Fe3O4 particles were unifomly attached to the surfaces of the orthohexagnal ZIF£­8 crystals£®And then the two magnetic nanoparticles were simultaneously introduced to extract 12 antibiotics residues in water samples by MSPE followed by HPLC£­MS/MS£®In order to establish the optimal extraction conditions£¬the key parameters influencing MSPE£¬i.e£®magnetic adsorbent amount£¬adsorption mode£¬adsorption time£¬sample pH£¬elution solvent and elution time were investigated in detail£®All the experiments were performed in parallel for three times£®In the adsorption procedure of MSPE£¬12 antibiotics could be extracted completely by the mixture use of 35 mg Fe3O4@SiO2@PLS and 15 mg Fe3O4@ZIF£­8 within 10 min£®Elution was performed using 10 mL 5% ammonia methanol for 5 min£®The target compounds were separated on an Agilent ZORBAX Eclipse Plus C18 column£¨100 mm ¡Á 3.0 mm£¬1.8 ¦Ìm£© by gradient elution£¬analysed in multiple reaction monitoring£¨MRM£© mode using positive electrospray ionization£¨ESI+£©£®Under the optimized conditions£¬good linearities were obtained for 12 antibiotics in the range of 0.5£­10 ¦Ìg/L£¬with correlation coefficients£¨r2£© of 0.996 1£­0.999 8. The limits of detection£¨LOD£¬S/N = 3£© and the limits of quantitation£¨LOQ£¬S/N = 10£© were in the ranges of 0.01£­0.14 ¦Ìg/L£¬0.04£­0.45 ¦Ìg/L£¬respectively£®The recoveries for 12 antibiotics at three spiked levels ranged from 75.0% to 107%£¬with relative standard deviations£¨RSD£© of 0.50%£­5.5%£®The proposed method is suitable for the simultaneous determination of trace sulfonamides and quinolones antibiotic residues in water samples£®