Abstract: The separation of six triazole pesticide enantiomers (TPEs) by ultra-performance convergence chromatography (UPC²) was attempted, and residue analytical methods for these TPEs in cucumber were established. The triazole pesticides were triadimefon, triadimenol, hexaconazole, tebuconazole, bitertanol, and myclobutanil. The sample was extracted with acetonitrile and cleaned up using graphitized carbon black (GCB), a Florisil-phase extraction column, and the QuEChERS method. The treated extract was separated on an Acquity Terifoil AMY1 chromatographic column, with gradient elution using a mixture of supercritical CO₂ and methanol or ethanol-isopropanol as the mobile phase. The residues of the six TPEs were quantified by the external standard method. The limits of quantitation (S/N>10) of these TPEs in cucumber were 0.1 mg/kg. The recoveries of the TPEs in cucumber at three spiked levels of 0.1, 0.2, and 0.5 mg/kg ranged from 65.1% to 116% with relative standard deviations (RSDs) of 1.0%-9.6%. The developed method facilitated the enantioseparation of the six TPEs and the accurate estimation of their residues in the cucumber matrix. This method is expected to play an important role in the production and utilization of chiral pesticides, as well as the establishment of relevant laws and regulations.

Key words: ultra-performance convergence chromatography (UPC²), triazole pesticides, enantiomer, chiral separation, residue