Quantitative Analysis of Pesticide Residues in Wheat

Wheat (Jimai 22) was provided by Crop Research Institute, Shandong Academy of Agricultural Sciences (Jinan, China). Flour (Fuqiang) was supplied by Beijing Guchuan Food Co., Ltd. (Beijing, China). The pesticide standards, including triphenyl phosphate (TPP), carbendazim, bensulfuron methyl, triazophos, chlorpyrifos, and carbosulfan (all 99% purity), were purchased from Accustandard Inc. (New Haven, CT, USA). The five pesticides (carbendazim, bensulfuron methyl, triazophos, chlorpyrifos, carbosulfan) chemical structures are shown in Figure 1. Chromatographic-grade methanol and formic acid were purchased from Mreda (Beijing, China), and 0.22 µm nylon membrane filter was purchased from Tianjin jinteng Experimental Equipment Co., Ltd. (Tianjin, China). Waters BEH C₁₈ column (100 mm × 2.1 mm, 1.7 μm) was purchased from Waters (Milford, CT, USA). QuEChERS purifier and salt package were purchased from Beijing Dima Outai Science Technology Co., Ltd. (Beijing, China).