Residues, degradation behavior of cyproconazole in Sichuan pepper and its dietary risk assessment


 In this study, an efficient method was developed and validated to determine cyproconazole in Sichuan pepper samples using the QuEChERS procedure and ultrahigh-performance liquid chromatography-tandem mass spectrometry. The average recoveries of the method were 96.2%-104.5% with the relative standard deviation (RSDs) below 7.6%, the limit of detection (LOD), and the limit of quantitation (LOQ) was 0.001 mg/kg and 0.02 mg/kg. The field trial results showed that cyproconazole in two Sichuan pepper matrices was rapidly dissipated with half-lives less than 8.8 days, which could be regarded as an easy degradation pesticide. The terminal residues of cyproconazole in Sichuan pepper samples were lower than the maximum residue limit (MRL) set by China (0.2 mg/kg registered on wheat). The calculated hazard quotient and acute hazard index lower than 100% illustrated that the use of cyproconazole, even at 1.5 times the highest recommended dose, does not pose any hazards to consumers.


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Sichuan pepper (Zanthoxylum bungeanum Maxim.) has been regarded as a common 29 household seasoning since the Spring and Autumn Period and Warring States Period in 30 ancient China . Besides, it has the effects of warming the middle gas, 31 eliminating cold, and relieving pain. Therefore, Sichuan pepper can be widely used as  Therefore, we focused on three specific aims in this study as follows: (1)  Sichuan pepper tree (it can be increased or decreased according to the size of the trees).

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It is necessary to ensure uniform spraying, and the application sequence was from the 180 control plot to the treatment plot.

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(1) 297 Here, D was the degradation rate; C0 was the initial concentration of the sample (mg/kg);

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Ct was the detected concentration of the sample (mg/kg); During the storage test, the 299 degradation rates are less than 30%, indicating that the cyproconazole is stable. By 300 contrast, if the degradation values are more than 30%, which indicates that it is unstable 301 during this period.  304 The dissipation pattern and degradation half-lives (DT50) of cyproconazole on Sichuan 305 pepper were evaluated by fitting the first-order kinetic model as follows:

Statistical analysis
Here, Ct and C0 are the residual level of cyproconazole (mg/kg) at time point t (day) 309 and the initial concentration (mg/kg), respectively. k is the degradation rate constants  The SPSS 20.0 software was utilized to perform a one-way analysis of variance on 312 the data. When P<0.05, it was considered that there was a significant difference. The The acute dietary exposure risk assessment (RQa) was evaluated by Eq. (5)    satisfactory retention on the chromatographic column, the peak shape and detection 372 sensitivity were significantly improved (Fig. 2). Therefore, acetonitrile-0.1% formic   Table S1, the intra-day recovery rate of cyproconazole in fresh Sichuan pepper sample was 96.2%~101.7%, the RSDr was 467 2.6%~4.4%; the inter-day recovery rate was 94.6%~98.7%, and the RSDR was   this study as the single exposure route to cyproconazole, and residents would also be 633 exposed to cyproconazole through various routes such as ingesting other fruits, 634 vegetables, and grains. Therefore, uncertain factors such as processing factors, average 635 residues, metabolites, and total dietary intake routes should be studied in-depth. 636 Meanwhile, more precise guidelines for safe and proper use should be formulated in 637 future researches.