Quantitative analysis of prometrine herbicide by liquid - Liquid extraction procedures coupled to electrochemical measurements

Abstract

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 × 10-3 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 × 10-7M, 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. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.