Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil

Abstract

Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70-120% with relative standard deviation ≤ 20% and HorRat values < 0.3-1.3. R was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible.

Residual behavior and dietary intake risk assessment of flonicamid, dinotefuran and its metabolites on peach trees

“…In the previous literature, the half-lives of flonicamid were 4.8 days in green tea shoots, 5 1.5-4.6 days in cabbages, 9 2.8-3.2 days in honeysuckles, 21 4.6-7.0 days in cottons. 23 Therefore, our results demonstrated that a longer dissipation behavior of flonicamid on peach trees than most reported crops, while shorter than the half-lives of flonicamid (7.6-19 days) in apples. 19 The dissipation behavior of dinotefuran in peach flesh isshown in Fig.…”

“…Additionally, the ME was analyzed by comparing the calibration slope between the matrix matching standard and the solvent standard. 23 The LODs referred to the corresponding amount of three times the matrix blank background response standard deviation. The LOQs were to determine the minimum amount of the analytes that can be quantified by analyzing a series of samples with known concentrations of the analytes with accuracy and precision to meet the requirements.…”

“…Several types of research had been reported that QuEChERS or solid-phase extraction technology combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-nitrogen phosphorus detector (GC-NPD), gas chromatography-electron capture detector (GC-ECD), high-performance liquid chromatography-diode array detection (HPLC-DAD), high-performance liquid chromatography-ultraviolet detector (HPLC-UVD), ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and ultra-high-performance liquid chromatography coupled to Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) could achieve the analysis of flonicamid, dinotefuran and its metabolites, separately. 5,9,10,16,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] In particular, the residual analysis and chronic dietary risk assessment of flonicamid on green tea, cabbage, cucumber, apple, potato, honeysuckle, cotton and paprika, 5,9,10,18-24 dinotefuran and its metabolites on cucumber, cotton, apple, Oryza sativa, eggplant, plum, orange, green tea, and melon 16,[25][26][27][28][29][30][31][32] have been carried out. However, to the best of our knowledge, studies on the degradation patterns and final residue levels of this mixture preparation on peach trees were still scarce so far, which were of great significance for the evaluation of its potential dietary intake hazards to consumers and for guaranteeing food safety.…”

Biodegradation of flonicamid by Ensifer adhaerens CGMCC 6315 and enzymatic characterization of the nitrile hydratases involved

“…Flonicamid ( N -cyanomethyl-4-trifluoromethylnicotinamide, FLO) is a novel systemic insecticide with selective activity that exhibits very good efficacy in pest control [ 1 – 3 ]. It is widely applied for foliar treatment of cabbages, tea trees, dwarf berry crops, and fruits [ 4 – 6 ].…”

Biotransformation of insecticide flonicamid by Aminobacter sp. CGMCC 1.17253 via nitrile hydratase catalysed hydration pathway

“…2018; Chawla et al . 2018). Despite of the toxicity and residues of flonicamid were lower than neonicotinoid insecticides, the toxic of flonicamid to natural enemies of pests had been reported.…”