IMPROVEMENT OF ANALYTICAL SUPPORT FOR CONTROL OF THE USE OF HERBICIDES BASED ON CARFENTRAZONE-ETHYL

Abstract

Introduction. According to modern requirements, control of the content of carfentrazone-ethyl (triazolone herbicide) in cereal grains and soil should be carried out taking into account its metabolite carfentrazone. The aim of the study is development of a method for determining carfentrazone-ethyl in cereal grains and soil as the sum of carfentrazone-ethyl and its metabolite carfentrazone expressed as carfentrazone-ethyl. Research Methods. Chromatographic analysis was performed on a Shimadzu Nexera X2 liquid chromatograph with a Shimadzu LCMS-8050 triple quadrupole mass spectrometric detector using a Shim-pack Velox Biphenyl, 2,7 μm, 100 × 2,1 mm, reversed-phase chromatographic steel column and Shim-pack Velox Biphenyl, 2,7 μm, 5 × 2,1 mm, precolumn. Soil and cereal grain samples were prepared according to the modular QuEChERS method. The recovery of the determination of carfentrazone-ethyl and carfentrazone in soil and cereal grain samples was confirmed by the “spike-recovery” method, and precision was confirmed by repeated measurements under conditions of repeatability and within-laboratory reproducibility. Results and Discussion. For the analysis of soil and cereal grain samples, the positive electrospray ionization mode (ESI+) and two MRM transitions (for quantitative calculations and for confirmation) were selected: carfentrazone-ethyl – 412 > 346,05, 412 > 366,00; carfentrazone – 384 > 346,10, 384 > 366,10. Optimal conditions of chromatography and mass spectrometric detection allowed the determination of carfentrazone-ethyl and carfentrazone in soil and cereal grains with a limit of quantification for each compound of 0,01 mg/kg (for the metabolite, this value is given in terms of carfentrazone-ethyl) with recovery from 70 to 120 %, repeatability ≤ 20 % and within-laboratory reproducibility ≤ 20 %. Conclusions. Methods for determining carfentrazone-ethyl (sum of carfentrazone-ethyl and its metabolite carfentrazone expressed as carfentrazone-ethyl) in cereal grains and soil with a limit of quantification in each matrix of 0,02 mg/kg with an expanded uncertainty of ≤ 50 % ensure control of medical and sanitary regulations standards for carfentrazone-ethyl established in Ukraine: in wheat and barley – 0,05 mg/kg; in soil – 0,6 mg/kg.