No abstract

The voltammetric determination of synthetic antioxidant 2,6‐di‐tert‐butyl‐4‐methylphenole (BHT) was studied using linear‐sweep voltammetry (LSV) and cyclic voltammetry (CV) with a gold electrode and performed in isopropanol media containing either 0.1 mol L−1 H2SO4 or 0.1 mol L−1 LiClO4 as supporting electrolyte. The results obtained have revealed that the most reliable detection was acquired in acidic media (isopropanol–H2SO4) whereas the use of isopropanolLiClO4 solution exhibited poorer reproducibility due to possible passivation of the electrode. Real samples of biodiesel mixture were analyzed without any special sample treatment or separation and results were compared with those obtained by FTIR‐spectroscopy.

In this article, a simple and rapid method is described for voltammetric determination of methiocarb (MTC, a pesticide of the carbamate type). Direct oxidation of MTC at a highly positive potential of about +1.4 V vs.Ag/AgCl was found to be feasible, thanks to the excellent performance of the working boron-doped diamond electrode in combination with the differential pulse voltammetric ramp. After optimisation of important parameters, the signal of MTC could be calibrated in an interval of 1-55 mg mL À1 MTC, when offering a detection limit (3s) of ca. 0.15 mg mL À1 MTC. The practical applicability of the method has been demonstrated on analyses of a commercial pesticide, either with respect to the total content of MTC or as its gradual and time-controlled dissolution in the model sample of the natural aquatic system.Scheme 1 Methiocarb (MTC).

A new method is proposed for determination of TBHQ (tert-butylhydroquinone) individually and in a mixture with BHT (butylated hydroxytoluene) in mineral oil and biodiesel when using linear-sweep voltammetry in combination with a gold disc electrode. Both of these analytes gave rise to the respective anodic peak in the supporting electrolyte based on a mixture of dilute H 2 SO 4 and isopropanol. The samples of mineral oil were extracted using ethanol, and the samples of biodiesel were analyzed without any special sample treatment or separation. The electroanalytical method developed has enabled the determination of antioxidants in model and real samples with satisfactory results and good prospects for practical analysis.