Determination of Inter-leaf Translocated Free Glyphosate in Arabidopsis thaliana using Liquid Chromatography Tandem Mass Spectrometry (LCMS/MS) after Derivatization with Fluorenylmethyloxycarbonyl Chloride (FMOC-Cl)

Misjudeen Raji Christoph Gehring

doi:10.4172/2155-9872.s2-007

Abstract

Glyphosate is a broad-spectrum herbicide widely used for eliminating weeds in crop fields. Its mode of action is believed to be via translocation from the source to the sink tissues where it then interferes with the activities of 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS). In this study, the translocation of glyphosate in the leaves of Arabidopsis thaliana was investigated using an HPLC-MS/MS method following derivatization of the secondary amino group in the analyte using N-(9-fluorenylmethoxycarbonyloxy) chloride. To eliminate the errant precipitation that occurred when the reagent and the analyte are mixed, optimization of this method was required. The method linearity has a correlation coefficient higher than 0.99 over the concentration range of 0.005-2 μM. The limits of detection and quantitation were estimated to be 0.002 μM and 0.008 μM respectively. The repeatability of the method (as%R.S.D) ranged from 10% to 13%. The presented method was employed for the determination of free glyphosate in young untreated leaves of the specimen plants after treating a single leaf and allowing it to stand for 12 hours.

Highlights

Glyphosate [N-(phosphonomethyl) glycine] is a non-selective herbicide that has gained considerable interest in recent years
The most widely used methods for analyzing glyphosate in various matrices and sample types are liquid chromatography coupled to UV-VIS detection, fluorescence detection, or electrospray tandem mass spectrometry [8,9,10,11], ion chromatography coupled with different detection methods such as conductivity and mass spectrometry [12,13], and Gas Chromatography coupled with Mass Spectrometry (GC-MS) [14,15] or with Flame Photometric Detection (GC-FPD) [16]
The Fluorenylmethyloxycarbonyl Chloride (FMOC-Cl) derivatization technique has been widely utilized in the analysis of glyphosate in different matrices, it is still important to perform an optimization of the procedure in order to ensure reliable results, when considering the investigation of unstudied matrices

Summary

Introduction

Glyphosate [N-(phosphonomethyl) glycine] is a non-selective herbicide that has gained considerable interest in recent years. The most widely used methods for analyzing glyphosate in various matrices and sample types are liquid chromatography coupled to UV-VIS detection, fluorescence detection, or electrospray tandem mass spectrometry [8,9,10,11], ion chromatography coupled with different detection methods such as conductivity and mass spectrometry [12,13], and Gas Chromatography coupled with Mass Spectrometry (GC-MS) [14,15] or with Flame Photometric Detection (GC-FPD) [16] Majority of these methods are not direct and involve many challenges. The FMOC moiety imparts some degree of non-polarity to the molecule while making it amenable to UV detection

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Conclusion