DETERMINATION OF 2,4-DIMETHYLPHENOL BY ANODIC VOLTAMMETRY AND FLOW-INJECTION WITH AMPEROMETRIC DETECTION AT A GLASSY-CARBON ELECTRODE

An electroanalytical study of the oxidation of 2,4-dimethylphenol (2,4-DMP) at a glassy carbon electrode in aqueous solutions using different voltammetric techniques has been carried out. The results obtained with differential-pulse voltammetry, using a pulse amplitude of 50 mV, in 0.1 mol l-1 perchloric acid and in a 0.1 mol l-1 Britton-Robinson buffer solution of pH 10.0 allowed the development of two methods for the determination of 2,4-DMP in the ranges from 2.0 X 10(-6) to 3.5 X 10(-5) and 2.0 X 10(-6) to 4.0 X 10(-5) mol l-1, with limits of detection of 7.2 X 10(-7) and 7.5 X 10(-7) mol l-1, respectively. Flow-injection methods with amperometric detection based on such an oxidation process are also described; calibration graphs were linear within the ranges 0.01-4.0 mg l-1 in 0.1 mol l-1 perchloric acid at a potential of +1.00 V and 0.01-5.0 mg l-1 in a 0.01 mol l-1 Britton-Robinson buffer solution of pH 10.0 at a potential of +0.75 V, with limits of detection of 4 and 7 mug l-1 (3.3 X 10(-8) and 5.8 X 10(-8) mol l-1) of 2,4-DMP, respectively. The proposed methods were applied to the determination of 2,4-DMP in water samples and good results were obtained.