RESUMO
A glassy carbon electrode modified with electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was developed for uric acid determination with dopamine as interference in artificial saliva. The electrochemical performance of the fabricated electrode was studied using both techniques of cyclic voltammetry (CV) and differential pulse voltammetry (DPV), under optimized conditions. Using DPV, the sensor based on ErGO/PEDOT:PSS modified GCE displayed a linear relationship in the concentration ranges of 10-100 µM for uric acid. This uric acid sensor exhibited a high sensitivity with detection limits of 1.08 µM and quantitation limit of 3.61 µM. This sensor also showed good reproducibility for uric acid detection in artificial saliva in 5 consecutive days of measurements. This device was successfully used to analyze uric acid in artificial saliva as well as in a human saliva sample using the standard addition method.
