Separation And Determination Of β-agonists And Phthalate Esters In Food

Food safety is a major issue which affects human health and safety. In addition to laws and regulations, we also need to develop scientific detection methods to comprehensively monitor the production, transportation, marketing and other aspects. At present, the devlopement of high selectivity and sensitivity analytical method and sample pre-treatment are the hot topics in the food analysis.A simple and efficient method based on a novel solid phase extraction (SPE) cartridge and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) has been developed for the determination of clenbuterol residual in pork. The novel SPE column based on homemade silica matrix with two mixed modes of reversed-phase and strong cation exchange provides selective enrichment and purification for the analyte. The linear range of the method was0.25-50μg/kg with a correlation coefficient of0.9982. The average recoveries ranged from62.2%to72.0%in the three spiked levels of1.25,12.5and50μg/kg with the relative standard deviations (RSDs) between4.2%and6.1%. The limit of detection (S/N=3) was0.05μg/kg. The method is simple, fast and can be extended to enrich and determine β-agonists drugs with similar structure.The separation of β-agonists was firstly performed on a silica-based weak cation exchange (WCX) stationary phase in which20mmol/L NH4FA(pH4.38) with5%ACN was used as mobile phase. This method bases on two mixed modes of reversed-phase and strong cation exchange and the interference from the hydrophobic analytes could be well eliminated due to their poor retention under this mode. The linear range of the method was25-1000μg/kg with a correlation coefficient above0.998. The proposed method can be directly applied for MS since the evaporative salt used in the method can match the requirement of MS. It believes much lower LOD will be achieved if MS is used to replace the fluorescence detector.Core-shell magnetite nanoparticles have unique separation performance and application prospects. Fe3O4@SiO2/C18(MNPs) were successfully synthesized and the extraction conditions were optimized to investigate the extraction efficiency of phthalate ester compounds from water samples by MNPs. It indicates that good recoveries could be achieved under the conditions of5ppb diethyl phthalate versus20mg MNPs activated by100μL methanol, ultrasonic time of10-20minutes and standing for15minutes.