Page 59 - 理化检验-化学分册2025年第三期

张延平：QuEChERS-气相色谱-三重四极杆串联质谱法同时测定锥栗中20种农药的残留量

Simultaneous Determination of Residues of 20 Pesticides in Castanea Henryi by
Gas Chromatography-Triple Quadrupole Tandem Mass
Spectrometry with QuEChERS

ZHANG Yanping
(Fujian Academy of Forestry, Fuzhou 350011, China)

Abstract: The Castanea henryi sample (5. 00 g) was taken and placed into a 50 mL-plastic centrifuge tube, followed by
the addition of 15 mL of water. The mixture was shaken well and settled for 30 min. A ceramic homogenizer was added to the
centrifuge tube, followed by 15 mL of a mixed solution of acetic acid and acetonitrile at volume ratio of 1∶99. The tube was
placed in an ice-water bath, and then 6. 0 g of magnesium sulfate anhydrous and 2. 0 g of sodium acetate anhydrous were added.
After the rapid and intense shaking, the mixture was settled for 10 min in the ice-water bath and then centrifuged for 5 min. 8 mL
of the supernatant was placed to a 15 mL-centrifuge tube containing 1 000 mg of magnesium sulfate anhydrous +300 mg of
C 18 +300 mg of N-propylethylenediamine (PSA). The mixture was vortexed for 5 min and centrifuged for 5 min. An aliquot
(2 mL) of the supernatant was taken and blown to near dryness by nitrogen at 35 ℃ in water bath. After ethyl acetate was added
to 1 mL, the mixture was vortexed and homogenized, and passed through a 0. 22 µm organic filter membrane. The residues
of 20 pesticides in the filtrate were determined by gas chromatography-triple quadrupole tandem mass spectrometry. The
20 pesticides were separated on HP-5MS UI column by programmed temperature, ionized by EI ion source, detected by multiple
reaction monitoring (MRM) mode, and quantified by external standard method with matrix matching mixed standard solution
series for drawing working curves. It was shown that linear relationships between the mass concentrations and the corresponding
−1
quantitiative ion pairs peak areas of 20 pesticides were kept in the range of 5—500 μg · L , and detection limits (3S/N) ranged
from 0. 051 μg · kg −1 to 1. 4 μg · kg −1 . Test for recovery was made according to standard addition method, giving recoveries in
the range of 79. 2%—97. 1%, and RSDs (n=6) of the determined values were less than 8. 0%.
Keywords: QuEChERS; Castanea henryi; gas chromatography-triple quadrupole tandem mass spectrometry; pesticide
residue

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