A rapid screening color test for glyphosate using dabsyl derivatization

Abstract

Purpose: Glyphosate is the most common herbicide in the world, and involved in many poisoning cases. However, the analysis of glyphosate has been difficult because of its high polarity and zwitterionic structure, and no simple screening tests for glyphosate have been known. The purpose of this study was to develop a rapid screening test for glyphosate. Methods: Glyphosate was visualized through a color change induced by dabsyl derivatization, and the derivatized glyphosate was trapped on the surface of zirconia-coated silica particles by specific chemical interaction between a phosphonate group of glyphosate and the zirconia surface. The presence of glyphosate was indicated by the color change of zirconia surface, which was easily noticed by the naked eye. Results: The developed method was applied to biological samples (urine and serum), beverage samples (green tea and cola drink), and soil samples. No false positive was observed and the detection limit was 100 μg/mL for the biological samples and 800 μg/mL for the beverage samples. Conclusions: A simple screening method for glyphosate based on a color test was established. The method is rapid and requires less than 30 μL of samples. The sensitivity was sufficient for most cases of moderate to severe poisoning.