New type of microfabricated carbon electrodes for high-performance liquid chromatography—Amperometric detection of fat-soluble vitamins and antioxidants

This study evaluates performance of thin-film carbon electrodes prepared by physical vapor deposition of the electrode material on a polyetheretherketone substrate and compares their performance with that of a standard type of glassy carbon electrodes for chromatographic detection cell of thin-layer type. Kaempferol, retinol, retinyl acetate, cholecalciferol, α-tocopherol and γ-tocopherol were selected for the study and their respective detection limits were found to be 0.63, 5.84, 5.91, 28.19, 16.80 and 16.11 pg. The calibration plots were linear for at least three orders of magnitude for all of the six analytes selected for evaluation. Hydrodynamic voltammograms are shown for both types of electrodes for the range of working electrode potentials between +0.40 and +1.40 V. Also shown and discussed are plots of signal-to-noise vs. detection potential. The working electrode potential of +1.30 V was found to be required for an improved long-term stability of detection performance and was suitable for the detection of all six analytes.