205650-65-3Relevant articles and documents
Chiral resolution of the insecticide fipronil enantiomers and the simultaneous determination of its major transformation products by high-performance liquid chromatography interfaced with mass spectrometry
Paolini, Léa,Hausser, Nicolas,Zhang, Tong
supporting information, p. 473 - 483 (2022/01/22)
A high-performance liquid chromatography–mass spectrometry (HPLC-MS) method was developed using a chiral column based on amylose tris(3-chloro-5-methylphenylcarbamate) for analysis of fipronil (a popular insecticidal nerve agent) and the related transformation products. The optimized method reached the goal of the simultaneous and complete separation of the multiple fiproles in a single run, including the chiral separation of fipronil enantiomers, fipronil metabolites, and photoproducts. The efficacy of such a method was demonstrated by its application in analyzing a series of fipronil samples exposed to sunlight conditions. In general terms, our study provided experimental approaches and an efficient analytical tool for monitoring the environmental fate of fipronil as well as its multitransformation products upon its applications either in agricultural or any other areas.
Kinetics and Mechanisms of Abiotic Degradation of Fipronil (Hydrolysis and Photolysis)
Bobe, Alain,Meallier, Pierre,Cooper, Jean-Francois,Coste, Camille M.
, p. 2834 - 2839 (2007/10/03)
The abiotic degradation of fipronil (compound I), a phenylpyrazole insecticide, was studied in aqueous solution and on the surface of two soils from Niger (Saguia and Banizoumbou) and one Mediterranean soil (Montpellier). The rate of hydrolysis of fipronil in solution was measured at different values of pH and temperature. The pH was an influencing factor: hydrolysis kinetics were pseudo-firstorder, the half-life being 770 h at pH 9.0, 114 h at pH 10.0, 11 h at pH 11.0, and 2.4 h at pH 12.0. Fipronil was stable under acid (pH 5.5) and neutral conditions. The Arrhenius relation was verified over the temperature range 22-45 °C: the activation energy was 62 kJ mol-1 and the calculated entropy change -32 J mol-1. Compound II [5-amino-3-carbamoyl-1-(2,6-dichloro-4-(trifluoromethyl)-phenyl)-4- [(trifluoromethyl)sulfinyl]pyrazole] was the only hydrolysis product detected. The hydrolysis reaction mechanism involves nucleophilic addition of OH- to the polar nitrile bond, producing a hydroxyimine which then undergoes tautomerization into an amide. Fipronil in acidic (pH 5.5) aqueous solution exposed to light from a xenon lamp degraded with first-order kinetics (Kobs, = 1.7 h-1) with concomitant appearance of 5-amino-3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(trifluoromethyl) pyrazole (compound III) and 5-amino-3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)-phenyl)pyrazole-4-sulfonic acid (compound IV). The photolyte formation rate constants were 0.11 h-1 (III) and 0.05 h-1 (IV). The observed degradation process corresponded to a desulfinylation and an oxidation. The reaction mechanisms were not elucidated. The irradiation (xenon lamp) of fipronil adsorbed on three natural soils when dry led to the formation of 4-(trifluoromethyl)pyrazole (III). The Kobs values were 0.0047 h-1 (Saguia), 0.0039 h-1 (Banizoumbou), and 0.0032 h-1 (Montpellier). The degree of photodegradation was inversely proportional to fipronil adsorption: the Freundlich adsorption coefficients were, respectively, 4.3 (Saguia), 7.3 (Banizoumbou), and 45.5 (Montpellier).
