Decline pattern and risk assessment of cyenopyrafen in different varieties of Asian pear using liquid chromatography and tandem mass spectrometry

摘要

The dissipation pattern of a commercial cyenopyrafen formulation sprayed at the recommended dose on Asian pears (two different species) grown at two different sites was investigated using liquid chromatography–ultraviolet detection. Samples collected randomly over 14 days were extracted using acetone, partitioned using n-hexane/dichloromethane (8/2, v/v), and purified using a Florisil solidphase extraction cartridge. The residues in field-incurred samples were confirmed via liquid chromatography–tandem mass spectrometry. The method was validated in terms of excellent linearity in the solvent (R ²=1); moreover, satisfactory recoveries (89.0–107.3%) were obtained at three fortification levels with a relative standard deviation (RSD)≤5.0% and the limits of detection and quantification of 0.0033 and 0.01 mg/kg, respectively. Although the residual levels at both sites were lower than the maximum residue limit (MRL=1 mg/kg), the dissipation at Site 2 was faster than that at Site 1. Consequently, the half-life (t1/2) in Site 2 (5.2 d) was shorter than that in Site 1 (9.8 d). Risk assessment at zero days showed acceptable daily intakes (%) of 27.25% and 24.52% at Sites 1 and 2, respectively, indicating that these fruit species are safe for consumption.