ABSTRACT
A rapid analytical method for simultaneous determination of 32 kinds of multi-residue veterinary drugs in eggs was developed using a modified QuEChERS technique based on a reduced graphene oxide-coated melamine sponge(r-GO@MeS)by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The influences of graphene oxide(GO)concentrations,sponge dosages,and purification modes on drug recoveries were investigated during the purification process.The optimal purification conditions involved using a GO concentration of 0.5 mg/mL,a sponge dosage of 6.0 cm3/mL,and a dynamic purification mode of 5 extrusion cycles.Separation was achieved using an Agilent Eclipse Plus C18 RRHD column(100 mm×2.1 mm,1.8 μm),and quantitative analysis was performed by the external standard method using an electrospray ionization source(ESI)in multiple reaction monitoring(MRM)mode.The results showed that all 32 kinds of veterinary drugs exhibited good linear correlation with coefficients greater than 0.999,and matrix effects(MEs)ranging from?7.8%to 18.9%.The limits of detection(LODs)and quantification(LOQs)ranged from 0.2 to 10.2 μg/kg and from 0.6 to 28.0 μg/kg,respectively.The recoveries for the three spiked levels were in the range of 66.5%?117.5%,with intra-day and inter-day precision(Relative standard deviation)below 13.3%and 16.3%,respectively.The synthetic r-GO@MeS exhibited efficient matrix purification without the need of high-speed centrifugation or strong magnetic field assistance.This significantly shorted the sample pretreatment time and improved the convenience of the matrix purification process.Combined with UPLC-MS/MS,the method was suitable for the rapid determination of multi-residue veterinary drugs in eggs.