Rapid Residue Determination of Cyenopyrafen in Citrus Peel,Pulp, and Whole Fruit Using Ultra-Performance Liquid Chromatography/Tandem Mass Spectrometry

A sample pretreatment method was established to analyze the residues of cyenopyrafen in citrus peel, pulp, and whole fruit using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The target compound was extracted from all matrices with acetonitrile and then cleaned by dispersive solid phase extraction using 10 mg GCB?+?150 mg MgSO₄ for citrus peel; 50 mg PSA?+?150 mg MgSO₄ for citrus pulp, and 50 mg C18?+?50 mg PSA?+?150 mg MgSO₄ for whole fruits. Determination of the target compound was achieved in less than 5.0 min using an electrospray ionization source in positive mode. Average recoveries in citrus peel, pulp, and whole fruit spiked at 0.01, 0.2, and 2 mg kg^?1 ranged from 84.9 to 105.1%, with relative standard deviations (RSD_r) of 0.7–7.9%. The reproducibility (RSD_R) ranged from 2.6 to 6.8%. The limits of detection and quantification ranged from 0.00032 to 0.0012 mg kg^?1 and from 0.0009 to 0.0036 mg kg^?1, respectively. This method was used to determine cyenopyrafen residues in citrus fruits to study its dissipation under field conditions. The trial results showed that the half-lives of cyenopyrafen in whole fruits were 10.2 and 6.2 days in Hunan and Guangxi provinces, respectively. The developed analytical method provides a basis to establish maximum residue limits and monitor cyenopyrafen residue in citrus.