Hierarchical Porous Carbon Derived from Pyrolysis of Sodium Citrate for Sensitive Determination of Dopamine and Uric Acid

Abstract

Hierarchical porous carbon (HPC) was simply prepared through pyrolysis of sodium citrate and further used as modified material for the determination of dopamine (DA) and uric acid (UA). Compared with a conventional glassy carbon electrode, the modified sensor achieved a larger active area and a faster electron transfer rate due to the high specific area and unique hierarchical porous construction. The separate and simultaneous analysis of DA and UA using the modified electrode was carried out by amperometry (AP) and differential pulse voltammetry (DPV), respectively. For separate measurement of each analyte, the linear ranges were 0.027–417 μM and 0.13–806 μM for DA and UA, with the detection limits (S/N = 3) of 0.012 and 0.06 μM, while for simultaneous detection, it exhibited the linear detection ranges of 0.04–100μM for DA and 0.2–100μM for UA, with the detection limits (S/N = 3) of 0.018 and 0.07 μM, respectively. In addition, the sensor is applied to simultaneous detection of DA and UA in spiked samples of juice, milk and urine samples, and satisfactory recoveries were obtained (97.0–104.0%). The results demonstrated that the modified HPC sensor has the advantages of simplicity, sensitivity, and practicality.