The invention relates to a method for determining
pesticide residues, in particular to a method for rapidly separating and quantitatively determining
dinotefuran enantiomers in a cucumber sample, an analysis
system and application of the
dinotefuran enantiomers. The method comprises the following steps: extracting a cucumber sample by using a 1%
acetic acid-
acetonitrile solution, purifying the cucumber sample by using a Pestii-Carb / PSA
solid-phase extraction small column, fixing the volume by using isopropanol / n-
heptane (2: 8, v / v), introducing the sample into a UPC2
system equipped with a CHIRALPAK AD-3 chiral
chromatographic column, and realizing baseline separation of (+)-(S)-
dinotefuran and (-)-(R)-dinotefuran within 4 minutes under the conditions of supercritical CO2 /
methanol gradient elution, proper
column temperature and
back pressure. The method is good in
linearity within the range of 0.5-20.0 mg / L, the quantitation limits of the two enantiomers in the cucumber matrix are both 0.1 mg / kg, the adding standard
recovery rate is 80.4%-106%, and the
relative standard deviation is not larger than 7.5%. The method and the
system have the advantages of high analysis speed, low
solvent consumption and high sensitivity and precision, and are suitable for conventional monitoring and
risk assessment of dinotefuran
enantiomer residues in vegetables such as cucumbers and the like.