Dual electrochemical sensor based on graphene aerogel for quantification of ascorbic acid in pharmaceutical samples and uric acid in urine

This work presents the advantages of modifying glassy carbon electrodes with a graphene aerogel (GA) dispersed in polyethylenimine (PEI). The presence of GA entrapped in PEI produces a catalytic effect that greatly facilitates the separation of the anodic peaks of ascorbic acid (AA) and uric acid (UA), enabling their detection and quantification by differential pulse voltammetry (DPV). The result is a highly efficient dual electrochemical sensor with a sensitivity of approximately 2.13 × 104 µAM− 1 for AA and 5.0 × 104 µAM− 1 UA. The current response showed a linear relationship for AA when the concentration ranged from 1.0 to 10 × 10− 4 M, with a minimum detection concentration of 0.25 µM and a relative standard deviation (RSD) of 2.0%. For UA, the lineal range was 1.0–15.0 × 10− 5 M, with a minimum detection concentration of 9 µM and an RSD of 2.8%. The promising analytical performance, which allows the evaluation of AA and UA, enables accurate quantification of AA in pharmaceutical samples and UA in urine without the use of enzymes or pretreatment.