Electrochemical sensor based on carbon material derived from Physalis alkekengi L. husks for the analysis of ascorbic acid

The design of electrode materials for sensitive electrochemical sensors is important for the rapid detection of ascorbic acid. Using Physalis alkekengi L. husks (PaLH) as the carbon precursor, PaLH-derived carbon materials (PCM) were prepared by high temperature carbonization, and hierarchical porous carbon materials (KPCM) were prepared by KOH activation. The carbon materials were characterized by scanning electron microscopy, X-ray diffraction, and isothermal nitrogen adsorption and desorption. KPCM had a larger specific surface area (1345.45 m(2) g(-1)) and more micro/mesopores than PCM without KOH activation. Two types of carbon materials, PCM and KPCM, were used as electrode modifiers, and the electrochemical properties of KPCM/GCE and PCM/GCE (GCE = glassy carbon electrode) were investigated. KPCM/GCE had a higher electron-transfer rate, higher electrochemically active area, smaller charge-transfer resistance, wider potential window, and higher catalytic activity for ascorbic acid detection. An ascorbic acid electrochemical sensing platform constructed with KPCM/GCE showed high sensitivity (334.03 mu A mM(-1) cm(-2) and 134.52 mu A mM(-1) cm(-2)) and a low detection limit (0.92 mu M) (S/N = 3) in the linear range of 0.005-1.6 mM. This method was applied to the analysis and determination of ascorbic acid in chewable vitamin C tablets.