Simultaneous determination of residues of metalaxyl, cyazofamid and a cyazofamid metabolite in tobacco leaves and soil by liquid chromatography with tandem mass spectrometry

Abstract

A simple method was developed and validated for the simultaneous determination of metalaxyl, cyazofamid and the cyazofamid metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM) by liquid chromatography with tandem mass spectrometry. The three target compounds were extracted from tobacco and soil with acetonitrile containing 0.1% acetic acid, and the extracts were purified using octadecylsilane. The proposed method showed satisfactory linearity (R ≥ 0.9985) for the target compounds. The limits of detection for metalaxyl, cyazofamid and CCIM were 0.006, 0.06 and 0.06 mg/kg in soil and green tobacco leaves and 0.03, 0.3 and 0.3 mg/kg in cured tobacco leaves, respectively. The limits of quantification for metalaxyl, cyazofamid and CCIM were 0.02, 0.2 and 0.2 mg/kg in soil and green tobacco leaves and 0.1, 1 and 1 mg/kg in cured tobacco leaves, respectively. The average recoveries from soil and tobacco were 72.91-98.40% for metalaxyl, 76.73-105.80% for cyazofamid and 74.48-106.45% for CCIM. The relative standard deviation range was 1.23-6.99%. The developed method was successfully applied to analysis of residues of metalaxyl, cyazofamid and CCIM in real soil and tobacco samples. The results indicated that the established method could meet the requirement for the analysis of trace amounts of all three analytes in soil and tobacco.

Determination, residue and risk assessment of trifloxystrobin, trifloxystrobin acid and tebuconazole in Chinese rice consumption

“…When the ME value is <1, the analyte response is suppressed. When the ME value equals 1, no matrix effects have occurred (Wu et al, 2018). The data in The highest response value was obtained when the combination sequence was A3B2C1D3, which was consistent with the optimized pretreatment condition of the three compounds.…”

“…When the ME value is <1, the analyte response is suppressed. When the ME value equals 1, no matrix effects have occurred (Wu et al, ). The data in Table show that the MEs in brown rice, paddy plants and rice hulls were suppressing TFSA and TEB signals.…”

“…The MEs were evaluating the slope ratios of matrix‐matched and solvent calibration curves. The LODs of the three compounds were calculated at a signal‐to‐noise ratio of 3, and the LOQs were defined as the lowest spiked levels (Wu et al, ). Intra‐ and inter‐day recoveries and RSDs were used to express accuracy and precision, respectively.…”

Residue behaviours, dissipation kinetics and dietary risk assessment of pyaclostrobin, cyazofamid and its metabolite in grape

“…Previous studies have already shown that CCIM appears to be more acutely toxic than cyazofamid ( European Food Safety Authority 2016). LC as well as LC–MS have been used to analyse cyazofamid and CCIM. Dissipation of cyazofamid has been determined in tobacco and tomato .…”

“…LC as well as LC–MS have been used to analyse cyazofamid and CCIM. Dissipation of cyazofamid has been determined in tobacco and tomato . But field trials have seldom conducted for simultaneous determination of pyraclostrobin, cyazofamid and CCIM.…”