Determination of thymol using HPLC-ED with glassy carbon paste electrode

The use of glassy carbon electrodes (CPE) for the determination of tymol was studied. The amperometric detection with prior separation of tymol by HPLC is proposed. The optimum conditions have been found. The HPLC-ED limit of detection of tymol at + 1.1 V vs Ag/AgCl/3 mol L-1 KCl in the mobile phase consisting of diluted Britton-Robinson buffer pH 7-methanol 1:9 (v/v) was 2.9 x 10(-7) mol L-1 which was lower than that with UV detection at 276 ran. The repeatability of the new method for the determination of thymol using HPLC with amperometric detection, expressed as the relative standard deviation, was below 2% when the areas of the peaks were evaluated and below 5% when the peak heights were measured. The practial application of newly developed method of HPLC-FD determination was tested on samples of Septolete pastilles and thyme sirup.