Salt-templated three-dimensional porous carbon for electrochemical determination of gallic acid.

We report an electrochemical sensor based on three-dimensional porous amorphous carbon (3DPAC) for the sensitive and selective determination of gallic acid (GA). The tailor-made carbon was prepared via salt-templating in which the organic molecular precursor, i.e., glucose, was simply ground and carbonized with a eutectic mixture of LiBr and KBr at 800 °C in an inert atmosphere. Salt removal from the carbon-salt mixture with water yielded 3DPAC with a hierarchical porous structure and oxygen-containing functional groups. When employed as an electrochemical sensor, 3DPAC exhibited remarkable sensitivity (0.1045 µA pM-1 cm-2) with a lower detection limit of 0.434 pM at a signal-to-noise ratio of 3 and a linear response up to 1-150 pM for determination of GA. Under optimized test conditions, 3DPAC showed a superior peak current response for GA as compared to the glassy carbon electrode. In addition, ascorbic, uric, and caffeic acids did not interfere with the voltammetric detection of GA in terms of selectivity, stability, and repeatability. We envision that 3DPAC can provide a promising platform for the development of electrochemical sensors.