Unveiling the Superior Mechanism of Au‐SPE Compared With C‐SPE

Dopamine (DA) and uric acid (UA) are small biomolecules involved in various physiological and pathological processes in the human body. The simultaneous and accurate detection of these two substances is of great significance for the early diagnosis and monitoring of disease conditions such as Parkinson's disease and gout. In this study, we proposed a portable electrochemical platform based on the gold‐coated screen‐printed electrode (Au‐SPE) for parallel detection of DA and UA and explored the mechanism behind the enhanced performance of Au‐SPE. Both DA and UA possess electrochemical activity and display different oxidation peaks in electrochemical detection. Differential pulse voltammetry results show that the Au‐SPE‐based electrochemical biosensor can simultaneously detect the oxidation reactions of DA and UA at different potential value. Compared with the carbon‐modified electrode, Au‐SPE exhibits superior signal responses and linear ranges toward DA and UA. Density functional theory and Gibbs free energy analysis revealed that the AuNPs coating enhanced electron transfer and adsorption and made the oxidation reactions more thermodynamically favorable. The Au‐SPE‐based sensor exhibits good linear responses in the concentration range of 0.05–10 and 10–300 μM, with a detection limit of 0.02 and 4.12 μM in the parallel detection of DA and UA. In addition, the biosensor shows good selectivity for UA and DA and favorable recovery rate in artificial sweat, laying a certain foundation for the development of portable and easy‐to‐use electrochemical biosensors.