Detection of agricultural residue parameters in agricultural products

This standard specifies the gas chromatography-mass spectrometry multi residue determination method for 305 pesticides (see Appendix A) in vegetables and the liquid chromatography-mass spectrometry multi residue determination method for 29 pesticides (see Appendix C). This standard is applicable to the determination of 334 pesticide residues in vegetables. The detection limit of this standard is 0.001mg/kg~0.05ng/kg (see Appendix A and Appendix C)

2 Principle: The sample was extracted with acetonitrile homogenate, and the extract was salted out, subjected to graphite carbon irradiation, and purified with a propylamine solid phase column. 305 pesticides were detected using a gas chromatography-mass spectrometry (see Appendix A). The mass spectrum is processed by deconvolution software, including noise processing, baseline drift correction, and identification of individual compounds in co elution harmonic peaks. Qualitative analysis is performed based on the processed mass spectrum and retention time, while internal standard method is used for quantification; The extract was purified by solid phase extraction with ethylenediamine-N-propyl (PSA) dispersion, and 29 pesticides were detected by liquid chromatography mass spectrometry (see Appendix C). Qualitative analysis was performed based on the selected ion abundance ratio and retention time, while quantitative analysis was performed using external standard method. Unless otherwise specified, only reagents and deionized water or water of equivalent purity confirmed to be analytically pure shall be used in the analysis. 3.1 Acetonitrile: Chromatically pure. 3.2 Methanol: Chromatically pure. 3.3 Toluene: Chromatically pure. 3.4 Acetone: Chromatically pure. 3.5 Anhydrous magnesium sulfate: Bake at 500 ℃ for 4 hours, cool to room temperature in a dryer, and store in a dryer for future use. 3.6 Mobile Phase A: Accurately weigh 0.385 g of ammonium acetate, dissolve it in 1000 mL of methanol, and pass through a 0.22 μ m filter membrane. 3.7 Mobile phase B solution: Accurately weigh 0.385 g of ammonium acetate, dissolve it in 1000 mL of water, and pass through a 0.22 μ m filter membrane. 3.8 Ethylenediamino-N-propyl (PSA): 40 urm, 60&. 3.9 Graphite carbon black solid-phase extraction column: volume 6 mL, packing 500 mgo3.10 propylamine solid-phase extraction column; Volume 6 mL, filling 500 mg e3.11 Pesticide standard: purity ≥ 95%. 3.12 Internal standard: Accurately weigh a certain amount of disinfectant, dissolve and dilute it with acetone to prepare a 1000 mg/L stock solution, and store it below -18 ℃. Take a certain volume of internal standard stock solution and gradually dilute it with acetone to 5 mgL of internal standard addition solution

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