<p>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.</p> Graphical abstract <p></p>