Untargeted screening, method validation, and dietary risk assessment of pesticide residue in coix seed using HPLC-MS/MS

Description

In this study, a multi-residue analytical method for pesticides in coix seed was constructed based on the non-targeted screening technique of HPLC-HRMS. A positive detection rate of 25.4% was found by systematic testing of 126 coix seed samples, with 39 pesticide residues, among which 6 pesticides, including dichlorvos, had residues exceeding the European Union's MRLs. This data was used as supplementary material for the article “Untargeted screening, method validation, and dietary risk assessment of pesticide residue in coix seed using HPLC-MS/MS” and contains the following: Figure Captions Figure S1. Matching information of six quality control compounds in the coix seed matrix. Figure S2. Mature seeds of four coix seed varieties: (a) CS1, (b) CS2, (c) CS3, (d) CS4. Figure S3. Distribution of the pesticide multi residues in all the samples. Figure S4 (1-13). The isotopic abundance of 37 pesticide residues in samples matches the degree of the database. Table S1. CAS number, molecular weight, and classification of 39 compounds. Table S2. Information on coix seed varieties. Table S3. Nontarget screening gradient elution procedure. Table S4. LC-MS/MS parameters of selected pesticides in coix seed. Table S5. Regression equations, correlation coefficients (R2), matrix effect (ME), mean recovery (%) for 39 pesticides in CS2. Table S6. Regression equations, correlation coefficients (R2), matrix effect (ME), mean recovery (%) for 39 pesticides in CS3. Table S7. Regression equations, correlation coefficients (R2), matrix effect (ME), mean recovery (%) for 39 pesticides in CS4. Table S8. Mean recovery (%), intraday (RSDR), and interday (RSDr) precision validation in CS2. Table S9. Mean recovery (%), intraday (RSDR), and interday (RSDr) precision validation in CS3. Table S10. Mean recovery (%), intraday (RSDR), and interday (RSDr) precision validation in CS4. Table S11. Detection rates and maximum residue limits of pesticides in 126 coix seed samples.

Steps to reproduce

Chemicals and reagents Standard materials with purity ranging from 95.0 to 99.9% were obtained from Beijing Tan Mo Quality Control Technology Co., LTD (Beijing, China) (Table S1). Acetonitrile, methanol, and formic acid were chromatographically pure purchased from Macklin Biochemical Co., Ltd (Shanghai, China). Analytical-grade NaCl and anhydrous MgSO4 were purchased from Chuandong Chemical (Group) Co., LTD. (Chongqing, China). Secondary amine (PSA), octadecylsilane (C18), and graphitized carbon black (GCB) were purchased from Bonaigel Technology Co., LTD. (Tianjin, China). Distilled water purchased from A.S. Watson TM Limited. (UK). Extraction and cleanup procedure A sample of coix seed that passed through a 40-mesh standard sieve was placed on an inclined plane. The grains flowed smoothly and at a relatively uniform rate, indicating that the size and shape of the milled grains were relatively uniform and homogeneous. The homogenized sample (5 g ± 0.01g) was weighed into a 50 mL polypropylene tube and mixed with 10 mL distilled water (Same treatment for blank samples). Acetonitrile (10 mL) containing 2% formic acid was added, and the mixture was left to stand for 30 min. Anhydrous MgSO4 (4 g) and NaCl (3 g) were added. The sample mixture was vigorously shaken in a multi-tube vortex for 5 min and centrifuged at 8000 rpm for 5 min. After centrifuging, the supernatant layer (1.5 mL) was transferred into a 2 mL centrifuge tube containing 100 mg octadecylsilane, 100 mg secondary amine, 15 mg graphitized carbon black, and 200 mg anhydrous magnesium sulfate. The 2 mL centrifuge tube containing the sample was vortexed for 2 min and then centrifuged at 8000 rpm for 5 min. The purified solution was filtered using a 0.22 µm organic filtration membrane and assayed by HPLC-MS/MS. Non-targeted screening Nontarget analysis was performed using an Orbitrap Exploris 240 quadrupole electrostatic field orbitrap benchtop mass spectrometer (Thermo Scientific, Waltham, Massachusetts, USA). Chromatographic separation was performed on a Kinetex F5 core-shell column (100 mm × 2.1 mm × 1.7 µm; Phenomenex, Torrance, CA, USA). Quantitative instrumental methods The coix seed sample was quantified and analyzed using a Vanquish TSQ Altis Plus high-performance liquid chromatography-tandem triple quadrupole mass spectrometer (Thermo Scientific, Waltham, Massachusetts, USA) paired with a Hypersil GOLD C18 chromatographic column (100 mm × 2.1 mm, 1.9 µm; Thermo Scientific, Waltham, USA).

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