A Fast and Simple Analysis of Glyphosate in Tea Beverages by Capillary Electrophoresis with On-Line Copper(II)-Glyphosate Complex Formation

Abstract

Glyphosate is an herbicide used for many plants that can be toxic to humans in high doses. Current methods for measuring glyphosate are slow and expensive. Here we describe a fast and simple method for measuring glyphosate in tea beverages by capillary electrophoresis with on-line formation of copper(II)-glyphosate complex. The optimum running conditions were found to be 40 mM acetate buffer (pH 5.0) containing 5 mM CuSO4 with an effective voltage of +15 kV using a sulfonated capillary (FunCap-CE Type S) and direct UV detection at 250 nm. Linearity (r2>0.999) was demonstrated in the range 5-1000 mg/l of glyphosate. Good reproducibilities of peak area (relative standard deviation <1.2%) and migration time (relative standard deviation <0.2%) were obtained. Recovery of glyphosate was between 98 and 100%. With this method, a tea beverage that was mixed with a glyphosate formulation was successfully analyzed.