Methodical approaches to scale-up measurement of glyphosate concentration using HPLC-FLD

Abstract

Introduction. Traditionally, the hygienic assessment of working conditions when using glyphosate preparations, an extremely popular herbicide in the world, is based on the use of thin layer chromatography. In this paper, alternative approaches are considered. On the basis of experimental data, the conditions for the analysis of glyphosate content in air by high performance liquid chromatography were optimized. Material and methods. All work with glyphosate solutions was carried out in polypropylene vessels. Sampling from the air medium was carried out on a medium filtration filter (“blue ribbon”). Subsequent extraction was carried out with water. The measurements were performed by high performance liquid chromatography with a fluorimetric detector at an excitation wavelength of 270 nm and an emission wavelength of 313 nm. To transfer glyphosate to a molecule with fluorimetric properties after derivatization of glyphosate in an alkaline medium using 9-fluorenylmethyl chloroformate by heating and washing off the excess of the reagent with toluene. A C18 reverse phase column was used; ammonium acetate with the addition of acetic acid and acetonitrile were used as eluents. Results. Approbation of the developed technique was carried out on real samples taken during ground treatment of fallow fields and lands of industrial territories with glyphosate preparations. The detected levels of glyphosate did not exceed the lower limit of quantitative determination: 0.5 mg/m3 in the air of the working area and 0.025 mg/m3 in the atmospheric air (with maximum allowable concentrations of 1.0 and 0.1 mg/m3, respectively). Limitations. The study considers a limited number of chromatographic columns. The study is performed on 25 model samples of the air of the working area and atmospheric air. Conclusion. Based on the results of the work performed, methodological instructions “Measurement of glyphosate concentrations in the air by high-performance liquid chromatography” were formed and sent for metrological certification in the approved manner.