Method validation and residue analysis of methoxyfenozide and metaflumizone in Chinese broccoli under field conditions by liquid chromatography with tandem mass spectrometry

Abstract

Methoxyfenozide and metaflumizone are insecticides used on Chinese broccoli to prevent insects and increase yield. However, the residues are potentially harmful to the environment and consumers. In this study, the quick, easy, cheap, effective, rugged, safe method with high-performance liquid chromatography with tandem mass spectrometry was modified and validated for determination of methoxyfenozide and metaflumizone in Chinese broccoli. The clean-up efficiency of different sorbents including C 18 , primary secondary amine, graphitized carbon black, and carbon nanofiber was compared. Recoveries of the validated method were 71.8-94.6% with relative standard deviations of 1.5-3.2% and the limits of quantification were 0.01 and 0.005 mg/kg for methoxyfenozide and metaflumizone, respectively. A storage stability test showed almost no degradation of methoxyfenozide in Chinese broccoli, however, the degradation rate of metaflumizone was 22.9% after 10-wk storage at -20 • C. In field trials in four producing regions, the dissipation of both methoxyfenozide and metaflumizone in Chinese broccoli was fast, with half-lives of only 1.0-5.1 and 0.7-2.5 days, respectively. Terminal residues after application of the two pesticides were all below 1.0 mg/kg after 5 days.

Residue Behavior of Methoxyfenozide and Pymetrozine in Chinese Cabbage and Their Health Risk Assessment

“…Acetonitrile and acetone have generally been used as extraction solvents for agricultural products; thus, it has been reported that these solvents have high extraction efficiency in the process of extracting methoxyfenozide from agricultural products [27,28]. However, it is reported that pymetrozine is a highly polar pesticide (log Pow: −0.18, water solubility: 0.29 g/L), and it is necessary to adjust the pH by adding a weakly basic buffer solution to suppress ionization to achieve a high extraction efficiency [29,30].…”

Environmental fate and safety analysis of methoxyfenozide application to control litchi and longan pests

“…The vapor pressure, partition coefficient, and water solubility of methoxyfenozide were < 1.33 × 10 −5 Pa, log Pow 3.72 ± 0.04 at 24.7 ± 1.4 ℃ (pH 7), and 3.3 mg/L at 20 ± 0.5 ℃ (pH 7), and 3.3 mg/L methoxyfenozide, 2003). The methoxyfenozide dissipation rates of litchi and longan were slower than those previously reported for pak choi (initial concentrations = 2.8 mg kg −1 , half-life = 3.9 days) (Tang et al 2021 ), spinach (initial concentrations = 1.2–3.8 mg kg −1 , half-life = 1.4–3.0 days) (Feng et al 2022 ), Chinese cabbage (initial concentrations = 1.12–1.33 mg kg −1 , half-life = 1.2 days) (Wang et al 2022 ), Chinese broccoli (initial concentrations = 0.27–1.73 mg kg −1 , half-life = 1.0–5.1 days) (Bi et al 2021 ), and cauliflower (initial concentrations = 2.5–3.5 mg kg −1 , half-life = 0.14–4.38 days) (Sun et al 2019a , b ). The above reports include residue levels observed in vegetables and pesticide degradation during harvesting is generally faster due to the short growth cycle of vegetables.…”

Challenges in direct determination of Glyphosate and aminomethylphosphonic acid in water by liquid chromatography–tandem mass spectrometry at modified reverse phase columns: Effect of matrix interferences in fresh and hard water systems

“…Two different modified reverse phase columns; Acquity T3 and Xselect high-strength silica (HSS) pentafluorophenyl (PFP) were used in the present study considering the less column maintenance, wider pH and solvent compatibility, and longer lifetime than the previously reported columns [9][10][11][12][13][14][15]. Two methods (M1 and M2) were validated against the two analytical columns with acceptable chromatographic retention and separation [16][17][18][19][20]. Importantly, the compatibility of the test methods used for the analysis of Glyphosate in HW has not been adequately demonstrated in previous methods [21].…”