Simultaneous determination and method validation of difenoconazole, propiconazole and pyraclostrobin in pepper and soil by LC–MS/MS in field trial samples from three provinces, China

Abstract

A liquid chromatography-electrospray ionization tandem mass spectrometry method was developed for simple and accurate detection of the fungicides difenoconazole, propiconazole and pyraclostrobin in peppers and soil. Three fungicides residues were extracted from samples by acetonitrile and cleaned up by dispersive solid-phase extraction before instrumental analysis. The accuracy and precision of the method were evaluated by conducting an intra- and inter-day recovery experiment. The limits of quantification and detection of difenoconazole, propiconazole and pyraclostrobin in pepper and soil were 0.005 and 0.0015 mg/kg, respectively. The recoveries were investigated by spiking pepper and soil at three levels, and were found to be in the ranges 79.62-103.15% for difenoconazole, 85.94-103.35% for propiconazole and 80.14-97.69% for pyraclostrobin, with relative standard deviations <6.5%. Field experiments were conducted in three locations in China. The half-lives of difenoconazole, propiconazole and pyraclostrobin were 5.3-11.5 days in peppers and 6.1-32.5 days in soil. At harvest, pepper samples were found to contain difenoconazole, propiconazole and pyraclostrobin well below the maximum residue limits of European Union at the interval of 21 days after last application following the recommended dosage.

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

“…Different methods have been developed for the determination of pyraclostrobin, for example, gas chromatography which requires cumbersome sample preparation and large amounts of organic solvents . Capillary electrophoresis and subsequent liquid chromatography (LC) UV and mass spectrometry (MS) have been utilized for the determination of pyraclostrobin in different matrices, such as apple, citrus, pepper, peanut, rice, grape . Besides, attention has been paid to the change of pyraclostrobin in food processing such as rasin and paste preparation.…”

“…Besides, attention has been paid to the change of pyraclostrobin in food processing such as rasin and paste preparation. In addition, dissipation studies have been conducted in apple, pepper, peanut, banana, grape, giving half‐lives of 1.6 to 1.7 days in maize, 3.39–4.06 days in glasshouse strawberry, 10.3–11.2 days in peanut, 17.8–25.9 days in grape …”

Deposition amount and dissipation kinetics of difenoconazole and propiconazole applied on banana with two commercial spray adjuvants

“…8,9 The residues of difenoconazole and propiconazole in agricultural products and environmental samples have been mainly determined by HPLC-UV, 10 GC-ECD, 11 GC-FID, 12 and LC-MS/MS. 9,13,14 However, only a few studies have been conducted on the simultaneous determination of the residues of propiconazole and difenoconazole in banana matrices.…”

Investigation and Validation of Detection of Storage Stability of Difenoconazole Residue in Mango

“…Gas/liquid chromatography (GC/LC) and gas/liquid chromatography-mass spectrometry (GC/LC-MS) methods are mainly used for determination of difenoconazole [10][11][12][13]. Besides being accurate, these methods are timeconsuming due to complex processes involved, and thus, a large number of samples need to be stored for analysis.…”