Hierarchical porous carbon derived from waste amla for the simultaneous electrochemical sensing of multiple biomolecules

For the first time, highly porous and hierarchical carbon with high surface area (similar to 2430 m(2) g(-1)) has been prepared from waste amla fruits at different carbonization temperatures viz., 700 degrees C, 800 degrees C and 900 degrees C by a simple and eco-friendly method for the simultaneous electrochemical sensing of biologically important compounds such as ascorbic acid (AA), dopamine (DA), uric acid (UA) and nitrite. The porous carbon materials synthesized at 700 degrees C, 800 degrees C and 900 degrees C are denoted as ABC-700, ABC-800 and ABC-900, respectively. The structural and morphological evaluations of as-synthesized hierarchical porous carbon are carried out with advanced tools and the existence of porous morphology is ascertained. The morphology, amorphous nature, disordered nature, surface area, pore volume, thermal stability and elemental composition of the as-prepared porous carbon are investigated by SEM, HRTEM, Fr-IR, Raman, TGA, BET, XPS, EDAX and CHNS analysis. Compared with ABC-700 and ABC-900, the electrochemical sensing ability was higher in the case of ABC-800. Therefore, further electrochemical sensing studies are carried out by using ABC-800. The limit of detection for the simultaneous determination of AA, DA, UA and NO2- are 13.7 mu M, 3.2 mu M, 1.1 mu M and 3.3 pM, respectively. The sensitivity are (0.55, 0.01), (4.73, 0.11), 0.11 and 0.57 mu A cm(-2) mu M-1 and linear ranges are (33-166, 166-26470), (1.6-72, 82-2630), 1.6-4134 and 4.9-1184 mu M, respectively for AA, DA, UA and NO2-. The porous carbon based sensor also proves reliable operational stability, long time stability, selectivity and good antifouling properties. The porous carbon based sensor was successfully applied to the practical application for the detection of these biomolecules in the real samples of urine.