In this study, a sensitive and reliable analytical method, based on a modified Quick, Easy, Cheap, Effective, Rugged and Safe procedure, was established for determination of tebuconazole in jujube. After extraction with acetonitrile, the samples were cleaned up by dispersive solid-phase extraction with primary secondary amine, and determined by high-performance liquid chromatography tandem mass spectrometry. At fortification levels of 0.01, 0.1 and 2.0 mg kg , the average recoveries of tebuconazole in jujube were in the range 97.6-101.9%, with relative standard deviations of 1.5-3.5%. The dissipation and residual levels of tebuconazole in jujube under field conditions were investigated. Tebuconazole dissipated relatively slowly in jujube, with a half-life of 33.0 days. The terminal residue experiments of tebuconazole in jujube were conducted in four locations in China and the risk was evaluated using risk quotients (RQ). RQ values were found to be significantly lower than RQ = 1, indicating that the risk to human health of using the recommended doses of tebuconazole in jujube was not significant. This study could provide guidance for the safe and reasonable use of tebuconazole in jujube and serve as a reference for the establishment of limit of maximum residue in China.

A rapid, reliable, and sensitive method is reported for the simultaneous analysis of pyrifluquinazon and its main metabolite NNI-0101-1H in fruits (strawberry and cherry) and vegetables (cucumber and tomato) using high-performance liquid chromatography coupled with tandem mass spectrometry. A modified, quick, easy, cheap, effective, rugged, and safe procedure was used for the sample pre-preparation. The target analytes were extracted with acetonitrile and then cleaned up using dispersive solid-phase extraction procedure with primary secondary amine. Sample analysis was performed using electrospray ionization in positive mode. Good linearities with the correlation coefficients higher than 0.9991 were obtained in the range of 1-1000 μg/L under the optimized conditions. The average recoveries of the pyrifluquinazon and NNI-0101-1H were in the range of 71.4-106.0% with the relative standard deviations 1.8-11.8% in all matrices at three spiked levels (10, 100, and 1000 μg/kg). The limit of quantification 10 μg/kg was set as the lowest spiked level. The developed method is reliable and effective for the routine monitoring of pyrifluquinazon and its metabolite NNI-0101-1H in fruits and vegetables to ensure food safety.

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