Determination of Herbicides and Its Metabolite in Soil and Water Samples by Capillary Electrophoresis-laser Induced Fluorescence Detection Using Microwave-assisted Derivatization

• DOI: 10.2116/analsci.30.759
• Publication Date: 2014-07-09T23:10:07Z
• Authors: Liwei Cao; Tao Deng; Siliu Liang; Xiaofang Tan; Jianxin Meng
• Keywords: Herbicides; Lasers; Pesticide Residues; Reproducibility of Results; Fresh Water; Fluoresceins; 01 natural sciences; 6. Clean water; 0104 chemical sciences; Spectrometry, Fluorescence; Capillary Electrochromatography; Limit of Detection; Soil Pollutants; Water Pollutants; Microwaves; Fluorescein-5-isothiocyanate; Fluorescent Dyes

Methods were developed to determine glufosinate (GLUF), glyphosate (GLYP) and its metabolite, aminomethylphosphonic acid (AMPA) by capillary electrophoresis-laser induced fluorescence detection using 5-(4,6-dichlorotriazinylamino) fluorescein (DTAF) and fluorescein isothiocyanate (FITC) as the derivatizing reagents. To accelerate the labeling speed, a microwave-assisted derivatization method was adopted. The derivatizing reaction time was reduced to 180 and 150 s for DTAF and FITC, whose reaction time for conventional labeling was 50 min and 5 h, respectively. The optimum separation conditions for derivatives were as follows: a back ground electrolyte (BGE) of 30 mmol L(-1) sodium tetraborate containing 15 mmol L(-1) brij-35, hydrodynamic injection 15 s and a 10 kV separation voltage. Under these conditions, the LODs (S/N = 3) for DTAF derivatives were 0.32, 0.19 and 0.15 nmol L(-1) for GLUF, GLYP, and AMPA, respectively. The LODs (S/N = 3) for FITC derivatives were 2.60, 3.88 and 2.42 nmol L(-1) for GLUF, GLYP, and AMPA, respectively. The applicability of the developed method was demonstrated by the detection of the above herbicides and metabolite in water and soil samples.