Determination of Cyhalofop-butyl and Cyhalofop-acid Residues in Cereals and Oilseeds by QuEChERS-UPLC

Objective: The method of QuEChERS-UPLC was established for the simultaneous determination of cyhalofop-butyl and cyhalofop-acid residues in cereals and oilseeds. Methods: The accurately weighed 2.0 g and 5.0 g sample was extracted with 0.1% formic acid water-acetonitrile (1:1, V/V) as extractant, and then purified with dispersive solid phase extraction adsorbents, such as N-propyl ethylenediamine (PSA), C18, sodium chloride, anhydrous magnesium sulfate, etc. After the purified solution was filtered through a 0.22 μm filter membrane, it was eluted with 0.1% phosphoric acid aqueous solution-methanol-acetonitrile as the mobile phase for gradient elution, separated by ACQUITY UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) chromatographic column, analyzed and detected by UPLC, and quantified by external standard method. Results: In the range of 0.002~5 μg/mL, the mass concentration of cyhalofop-butyl and cyhalofop-acid showed a good linear relationship with the peak area, and the limits of quantification in grains and oils