Voltammetric determination of coenzyme Q(10) at a solid glassy carbon electrode

This paper reports a simple, sensitive, and accurate voltammetric method fo r the coenzyme Q(10) electroanalytical determination on a glassy carbon ele ctrode (GCE) from commercially available capsules, compared with a UV-VIS s pectrophotometric method. Cyclic (CV), linear sweep (LSV), and square-wave (SWV) voltammetry on GCE w as employed to explore the coenzyme Q(10) behaviour, using as supporting el ectrolyte, 0.12 M H2SO4 (in methanol) in hexane/methanol (1:2 vol.) mixture . The voltammograms showed the characteristic reduction peaks at potential values in the range of 0.190- 0.300 V vs. Ag/AgCl, depending on the techniq ue that was used. A linear dependence of the reduction peak height on the a nalyte concentration was obtained using LSV and SWV techniques in the domai ns 5 x 10(-6) - 7 x 10(-4) mol L-1,and 5 x 10(-7) - 7 x 10(-4) mol L-1 coen zyme Q(10) concentration. The detection limit was 10(-7) mol L-1 for SWV.