RESUMEN
A novel modification of a paste carbon electrode by Bentonite (Bent) and l-Cysteine (l-Cyst) was carried out for uric acid (UA) and ascorbic acid (AA) detection and quantification. Morphological and compositional characterization of the electrode surface were carried out using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopic analysis (EDS). Cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques were used to analyze UA and AA. The obtained sensor shows a good stability, sensibility, selectivity, and regeneration ability. Accordingly, the limit of detection (LOD) is found to be 0.031â µm and 9.6â µm for UA and AA, respectively. A good linearity in the range of 0.1 to 100â µm for UA and 10 to 1000â µm for AA was obtained. The peak-to-peak separation of UA-AA (ΔEUA-AA ) was determined to be 330â mV. In addition, the sensor is applied successfully to monitor UA and AA in serum samples.