Quantitative Analysis of Prometrine Herbicide by Liquid–Liquid Extraction Procedures Coupled to Electrochemical Measurements

A sensitive method is proposed for the preconcentration and quantification of the herbicide Prometrine (PROM) at a liquid‐liquid interface employing square‐wave voltammetry. The preconcentration stage was based on liquid‐liquid extraction methodology and the PROM quantification was carried out from the peak current of square‐wave voltammograms. Under the experimental conditions employed, linear calibration curves in the concentration range 1.0×10^?6 M–5.0×10^?5 M, with detection limit equal to 1.5×10^?6 M were obtained without pretreatment of the samples. This linear range, as well as detection limit could be extended towards lower concentrations when a pretreatment procedure was employed. In this way, linearity of calibration curves between 8.0×10^?8 M and 2.4×10^?7 M and detection limit of 1.0×10^?7 M, were observed. On the other hand, the standard addition method was also used as an alternative and an appropriated quantification technique for this system. A linear concentration range between 1.0×10^?6 M and 2.7×10^?5 M, with a correlation coefficient of 0.997, was obtained. This procedure has also a promising application in the separation of herbicides from other interferents, present in real samples, previous to their quantification.