Fig. 6 exhibits the LSVs of the OMC/GCE in the absence (a) and presence of FA: 50 (b), 100 (c), and 150 lM (d) in the 0.04 M B-R solution (pH 7.0) at a scan rate of 50 mV/s. It was observed that the voltammetric response increased with the increasing concentration of FA proportionally, representing that the OMC/GCE can be used as the quantitative determination of FA.