Determination of Pyroxasulfone Residues in Animal-derived Foods by Gas Chromatography£­Triple Quadrupole Mass Spectrometry

KeyWord:pyroxasulfone  animal-derived foods  gas chromatography£­triple quadrupole mass spectrometry

Abstract:

      A gas chromatography£­triple quadrupole mass spectrometry was developed for the rapid determination of pyroxasulfone residues in animal-derived foods£®Pyroxasulfone residues in pork£¬pig liver£¬chicken£¬chicken liver£¬milk and eggs were extracted with acetonitrile£¬and cleaned up with primary-secondary amine£¬stearyl bonded silica gel and anhydrous magnesium sulfate as dispersive solid-phase extraction sorbent£®After centrifugation£¬the supernatant liquid was nitrogen-blowed to dryness£®After redissolved with acetone and filtered£¬the analyte was detected by gas chromatography£­triple quadrupole mass spectrometry£¬and quantified by external standard method£®The instrument conditions£¬extraction solvents and purification method were optimized in the experiment£¬and the optimal pretreatment method and instrument conditions were obtained£®The detection effects of pyroxasulfone by triple quadrupole liquid chromatography£­mass spectrometry and triple quadrupole gas chromatography£­mass spectrometry were compared£®The results showed that the response of pyroxasulfone on triple quadrupole liquid chromatography£­mass spectrometry was poor£¬and the detection sensitivity could not meet the requirements of relevant regulations£¬while the detection effect of pyroxasulfone by triple quadrupole gas chromatography£­mass spectrometry was excellent£¬which could meet the detection requirements£®In addition£¬the extraction effects of hexane£¬acetone£¬ethyl acetate£¬acetonitrile and acidic acetonitrile as extraction solvents were compared£¬and the results showed that acetonitrile was the most suitable extraction solvent£®The matrix effect of the sample was investigated£¬and it was found that the matrix effects of pyroxasulfone in the six matrices were less than 20%£¬which were a weak matrix effect without compensation. Under the optimal conditions£¬the calibration curve was linear in the range of 0.5£­100 ¦Ìg/L with correlation coefficients of 0.999 5£® The limit of quantitation was 0.001 mg/kg. The average recoveries for blank samples at low£¬medium and high spiked levels ranged from 85.8% to 106%£¬with relative standard deviations£¨n = 6£© of 3.1%£­6.8%£®This method was used to determine 50 animal-derived foods£¬in which pyroxasulfone residues were detected in one beef sample and one mutton sample£®The method is simple£¬rapid and sensitive£¬and it could meet the requirements for detection of pyroxasulfone residue in animal-derived foods.