A Sensitive Voltammetric Sensor for Amaranth Based on Ordered Mesoporous Carbon

By using P123 (EO20-PO70EO20) as the surfactant and tetraethylorthosilicate (TEOS) as the silica source, a template of SBA-15 was prepared. By utilizing sucrose as carbon source to get the ordered mesoporous carbon (OMC), a voltammetric sensor for amaranth was constructed based on glassy carbon electrode (GCE) modified with OMC. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (XRD) and nitrogen adsorption-desorption isotherms displayed the highly ordered hexagonal pores and narrow mesopore size distribution of OMC. In comparison with the bare GCE and carbon nanotubes/GCE, the OMC/GCE exhibited larger electroactive surface area. OMC/GCE exhibited an enhanced electrochemical response toward the oxidation of amaranth in the neutral solution. In addition, some experimental parameters such as accumulation potential, pH values and accumulation time were optimized. The results showed that the peak current increased linearly with the concentration of amaranth from 1.0 x 10(-7) mol/L to 3.0 x 10(-6) mol/L at 0.72 V and the detection limit was 3.2 x 10(-8) mol/L(S/N = 3). The prepared sensor was successfully used in real samples analysis with satisfying results.