Assessment of methyl 2-({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl] sulfamoyl}methyl)benzoate through biotic and abiotic degradation modes

Detoxification and management of environmental contaminants is an exigent issue of current times. Sulfonylurea herbicide, Bensulfuron-methyl was investigated for its degradation demeanour in soils, through biotic and abiotic modes (biodegradation and hydrolysis). Solid-liquid extraction of the herbicide was followed by GC-MS and UV-visible spectrophotometry analysis. The main metabolites observed were pyrimidinamine [149 m/z] and benzylsulfonamide [182 m/z]. The rate of biodegradation achieved by Aspergillus niger and Penicillium chrysogenum was 95% and 71%, respectively. The maximal decline in Bensulfuron-methyl concentration through hydrolysis was 48%. Furthermore, hydrolytic elimination was also evaluated based on time and pH. Both these parameters had a strong influence on the rate of transformation. Soils with lower pH exhibited an increased rate of degradation while a temperature of 27±2°C gave ideal conditions for herbicide decomposition. Percentage degradation and rate constant (k) followed first order reaction kinetics. Non-inoculated soils displayed less amounts of degradation. Furthermore, relative standard deviations were calculated for the residuals extracted in all soils. Analysis of variance (ANOVA) provided a p value < 0.05 for both strains with R2 closer to 1 signifying the significance of the results. Both fungal strains proved their potential for Bensulfuron-methyl remediation in soils.

A Study of Electrolysis Technology for the Removal of Nicosulfuron from Dilute Aqueous Solution

Nicosulfuron is a kind of sulfonylurea herbicide used for controlling weeds in corn. In order to solve the problem of plant water with agrochemical, electrolysis was investigated for the treatment of nicosulfuron from dilute aqueous solutions. The operating varieles of time, chlorine anion, pH were experimented and the electrolytic decomposition mechanism of nicosulfuron was suggested. Acid solution was effective for the decomposition of the nicosulfuron and the existence of chloride ions lead to the formation of electrolytic reaction products, which regarded as chloronicosulfuron by HPLC-MS. The reaction is similar to free radical reaction.

Dispersive Solid–Liquid Extraction Coupled with LC-MS/MS for the Determination of Sulfonylurea Herbicides in Strawberries

The monitoring of food quality and safety requires a suitable analytical method with simultaneous detection in order to control pesticide and herbicide residues. In this study, a novel analytical method, referred to as “dispersive solid–liquid extraction”, was applied to monitor seven sulfonylurea herbicides in strawberries. This method was optimized in terms of the amount of C18 and the volume of added water, and it was validated through satisfactory linearities (R2 > 0.99), recoveries of 70% to 84% with acceptable precisions, and limits of quantification lower than the maximum residue limits for the seven sulfonylurea herbicides in strawberries. The cleanup efficiency of the dispersive solid–liquid extraction technique was compared to that of the QuEChERS- (“quick, easy, cheap, effective, rugged and safe”) based method with dispersive solid phase extraction. The recoveries of the former were found to be comparable to those involving QuEChERS C18 cleanup (recoveries of 74%–87%). The method was used to determine sulfonylurea herbicide residues in ten strawberry samples. None of the samples had herbicide residues higher than that of limit of quantifications (LOQs) or maximum residue limits (MRLs). The results suggest that the dispersive solid–liquid extraction method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) is effective for the analysis of sulfonylurea herbicide residues in strawberries.