An automated magnetic solid-phase extraction method for simultaneous determination of 22 nicotinic insecticides and fungicides in peach samples combined with ultra-high performance liquid chromatography-high resolution mass spectrometry

In this study, an automated magnetic solid phase extraction (MSPE) method was developed for the purification and determination of 22 pesticides including 12 nicotinic insecticides and 10 fungicides in peach samples. First, novel core-shell primary secondary amine (PSA)-modified magnetic titanium dioxide (Fe3O4@SiO2@TiO2-PSA) microspheres were synthesized in a controllable manner, and its morphology and composition were characterized. Then, the Fe3O4@SiO2@TiO2-PSA microspheres were used as an adsorbent for the purification of 22 pesticides in peach samples based on an automated MSPE method. The automated MSPE conditions, including the choice of magnetic adsorbents, adsorbent concentration and purification time, were carefully optimized. The obtained results indicated that the as-prepared Fe3O4@SiO2@TiO2-PSA microspheres can effectively reduce the matrix interference effect, and all 22 target pesticides showed mild matrix effects. Moreover, under the optimal conditions, the recoveries of 22 pesticides ranged from 74.6 % to 120 % and 86.6 %-119 % for peach skin and pulp samples, respectively, with RSDs ranging from 0.27 %∼9.71 % and 0.10 %-8.98 %, respectively. In addition, the developed automated MSPE-UPLC-HRMS method was used to monitor and investigate the distribution characteristics of pesticide residues in 100 peach skins and pulps. In conclusion, the method developed in this study is high throughput, rapid, accurate and suitable for routine analysis. •Synthesis of core-shell Fe3O4@SiO2@TiO2-PSA in a controlled manner.•An automated magnetic solid phase extraction method was developed for pesticides purification.•High purification efficiency toward 22 pesticides in peach samples were obtained.•Application to pesticide monitoring and distribution characteristics in peach samples.