New electroanalytical method for the determination of trans-anethole in spices and sweets.

ABSTRACT

A completely new method for the determination of trans-anethole (TAN) based on the anodic oxidation of this flavouring substance in pure acetonitrile using differential-pulse voltammetry has been developed. A nonaqueous carbon paste electrode bulk-modified with solid sodium dodecyl sulphate of 40 % (w/w) content was chosen as optimum. To propose TAN electrode reaction mechanism, its electrochemical behaviour was investigated at glassy carbon electrode in nonaqueous media. At optimum working conditions, the current response could be calibrated within a linear range 2-200 µmolL-1 TAN, a coefficient of determination of 0.9971, a sensitivity of 0.1122µALµmol-1, and a detection limit of 0.7 µmolL-1. A satisfactory precision (relative standard deviation of 4 %) has been achieved. The validation performed by analysis of spices and sweets provided comparable results with reference reverse-phase HPLC with spectrophotometric detection, thus confirming the practical use of the developed voltammetric method in food analysis.