Abstract: Two new types of elastic porous silanized melamine sponges (MeS) were prepared by silylation reaction using octadecyltrichlorosilane (OTS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (ATS), which were respectively represented as OTS@MeS and ATS@MeS. The above two synthetic silanized sponges were used to improve the convenience and speed in purification process of QuEChERS (quick, easy, check, effective, rugged, and safe) method. The interference matrix could be quickly and efficiently separated from the extraction solution through the spontaneous solution infiltration and physical extrusion process. In this study, a modified QuEChERS based on silylated melamine sponge was established for the simultaneous determination of 49 antibiotic residues in pork by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with 10 mL of acetonitrile containing 0.1% acetic acid, and then salted out by 2.0 g Na2SO4 and 0.5 g NaCl. After centrifugation, 1 mL of the supernatant was cleaned up with OTS@MeS and ATS@MeS by a soaking and squeezing process. The chromatographic separation was conducted on a Agilent ZORBAX Eclipse Plus C18 column with gradient elution using methanol and H2O-methanol containing 0.1% formic acid and 5 mM ammonium acetate as mobile phases. The qualitative and quantitative detection was performed by multiple-reaction monitoring scanning in a positive electrospray ionization mode. The result showed that the correlation coefficients for 49 antibiotics greater than 0.999. The matrix effects were located in the range of -13.5%~10.9%. The limits of detection (LOQ) and quantitation (LOQ) were 0.1–10.0 and 0.3–33.3 μg/kg, respectively. The recoveries at three spiked levels ranged from 65.0% to 112.7% with all intra- and interday relative standard deviations (RSDs) less than 11.8% and 18.4%, respectively. The developed method was simple, rapid, highly sensitive and accurate, and could be used for the efficient and rapid determination of the 49 antibiotics residues in pork.

Key words: silanized melamine sponge, ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), pork, antibiotics