Keywords: CZE, capillary zone electrophoresis, herbicides, liquid chromatography, MCPA, plant protection products, diode array detection
Development of a capillary zone electrophoresis method to determine 2-methyl-4-chlorophenoxyacetic acid in a plant protection product
Capillary zone electrophoresis (CZE) with diode array detection was successfully used for the analysis of 2-methyl-4-chlorophenoxyacetic acid (MCPA) herbicide in an aqueous commercial plant protection product. The performance of the method was studied in terms of accuracy, precision, linearity, Limit of Detection (LOD) and Limit of Quantification (LOQ). Accuracy, expressed as recovery rates, ranged from 92.8% to 101.2% with a RSD of 4.5%. Intra-day repeatability of both relative migration times and relative peak areas was satisfactory, being RSD 0.1% and 2.9%, respectively. Good linearity (r² > 0.99) was also obtained. The LOD of the active substance in the acidic form was 49 µM, whereas the quantification limit was found to be 150 µM. The analysis of the active ingredient content in a plant protection product has been performed also with liquid chromatography; the performance of this method has been studied and a comparison with CZE method has been conducted.