Rapid Determination of Trace Sulfonamides in Milk by Graphene Oxide-Based Magnetic Solid Phase Extraction Coupled with HPLC-MS/MS

A simple and rapid method based on magnetic solid-phase extraction (MSPE) combined with high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS) was used for the determination of 15 sulfonamides from milk samples. The extraction and cleanup used a graphene oxide-based magnetic nanocomposite (Fe3O4@GO) as an adsorbent. Various experimental parameters that could affect the extraction efficiencies, such as the amount of Fe3O4@GO, the extraction time, the ionic strength of sample solution, and the type of eluent, were investigated. Under optimized experimental conditions, good linearity was observed in the range of 2.0 to 100.0 mu g L-1 for all of the analytes, with correlation coefficients (R-2) ranging from 0.994 to 0.999. The limits of detection for the method ranged between 0.02 and 0.13 mu g L-1. Mean values of the relative standard deviation of intraday and interday precision ranging from 1.0 to 7.3 % and from 1.7 to 8.1 % were obtained, respectively. The average recoveries were between 73.4 and 97.4 % at three different spiked levels. It was confirmed that the Fe3O4@GO nanocomposite was an effective MSPE material for use in sulfonamide analyses in milk samples.