Development and validation of a method for the analysis of trifludimoxazin, picarbutrazox and pyraziflumid residues in cereals, vegetables and fruits using ultra-performance liquid chromatography/tandem mass spectrometry

Coconut shell biochar application in liquid-solid microextraction of triazine herbicides from multi-media environmental samples

A rapid, fast, widely applicable liquid-solid microextraction and purification method of triazine herbicides (TRZHs) in muti-media samples using salting-out assisted liquid-liquid extraction (SALLE) combined with self-assembled monolithic spin columns-solid phase micro extraction (MSC-SPME) was developed. Environmentally friendly coconut shell biochar (CSB) was used as the adsorbents of MSC-SPME. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was the separation and determination method. The adsorption kinetics and isotherms were investigated to indicate the interaction between CSB and TRZHs. Several parameters influencing the liquid-solid microextraction efficiency, such as sample pH, salting-out solution volume and pH, sample loading speed, elution speed, elution ratio and volume of eluent were systematically investigated with the aid of orthogonal design. The whole extraction process was operated within 10 min. Under the optimum extraction and determination conditions, good linearities for three TRZHs were obtained in a range of 0.10-200.00 ng mL^-1, with linear coefficients (R²) greater than 0.999. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 6.99-11.00 ng L^-1 and 23.33-36.68 ng L^-1, respectively. The recoveries of the three TRZHs in multi-media environmental samples were ranged from 69.00% to 124.72%, with relative standard deviations (RSDs) lower than 0.43%. This SALLE-MSC-SPME-UPLC-MS/MS method was successfully applied to the determination of TRZHs in environmental and food samples and exhibited the advantages of high efficiency and sensitivity, low cost, and environmental friendliness. Compared with the methods published before, CSB-MSC was green, rapid, easy-operated, and reduced the whole cost of the experiment; SALLE combined MSC-SPME eliminated the matrix references effectively; what's more, the SALLE-MSC-SPME-UPLC-MS/MS method could be applied to various sample without complicated sample pretreatment procedure.

Uptake and translocation of fungicide picarbutrazox in greenhouse cabbage: the significance of translocation factors and home processing

This study evaluated the uptake and translocation of the fungicide picarbutrazox (PBZ) and its isomer in greenhouse cabbage. Two distinct treatments, including foliar spray and soil application of PBZ, were used in this study. In the foliar application, the fungicide was sprayed thrice at intervals of 7 days from 30, 21, and 14 days before harvest following the OECD guidelines of fungicides in crops, whereas in soil treatment, PBZ was applied for one time at concentrations of 2 and 10 mg/kg, and cabbage was cultivated for 68 days. Additionally, the role of root and translocation factors during residual fungicide distribution was demonstrated. The quality control of the analytical study exhibited excellent linearity (R² ≥ 0.99), the limit of quantification (LOQ 0.005 mg/kg), accuracy (recovery within the range of 70-120%), and precision (relative coefficient within 0.3-13.8%) for studied PBZ and its metabolites. In the foliar application, initially higher amount of residual PBZ was evident in the outermost leaf of the cabbage, whereas in soil treatment, the highest residual PBZ was observed in the soil and roots. Therefore, the application method of picarbutrazox is a critical factor for defining the initial entry route of pesticides and the subsequent translocations through the investigated crops.