Gold nanoparticles decorated N-doped MOF-199 for simultaneous electrochemical determination of dopamine and uric acid in human serum and urine samples

• Hybrid Au@N-MOF-199 materials were synthesized via the in-situ growth of AuNPs on the surface of N-doped MOF-199. • The limits of detection were as low as 0.02 μM for DA and 0.03 μM for UA, with a broad linear range from 0.1 to 1000 μM. • The sensor enables on-site visualization and accurate quantitative determination of DA and UA in human urine and serum samples. • Satisfactory recoveries were achieved in spiked real samples, ranging from 99.30% to 107.67%. It is essential to quickly and effectively identify biochemical indicators in bodily fluids, especially when creating electrode materials. This study synthesized nitrogen-doped MOF-199 (N-MOF-199) using a polyvinylpyrrolidone (PVP)-assisted technique. Gold nanoparticles (AuNPs) were then added to Au@N-MOF-199 to enable the electrochemical detection of dopamine (DA) and uric acid (UA). Particle sizes in the N-MOF-199 and Au@N-MOF-199 composites range from 300 to 600 nm, and their octahedral shape is constant. The corresponding specific surface areas are 11.7 m 2 ∙g -1 and 55.26 m 2 ∙g -1 . These features enhance their electroanalytical capabilities in the simultaneous identification of biological markers. For DA, Au@N-MOF-199 showed a wide linear detection range (0.1 to 1000 μM) and a low detection limit (LOD) of 0.02 μM (S/N = 3). UA was found to have a linear range of 0.1-1000 μM and a detection limit of 0.03 μM (S/N = 3). While the inclusion of AuNPs significantly enhances electrical conductivity, the improved dispersion stability provided by PVP and nitrogen doping is the primary factor contributing to the enhanced sensing performance. The synergistic effects improve the material's electrochemical responsiveness overall. The findings lay a solid basis for the creation of high-performance sensors for a range of biological markers by highlighting the considerable potential of Au@N-MOF-199 composites as sensitive and selective substrates for the electrochemical detection of DA and UA. The Au@N-MOF-199 composite on a screen-printed carbon electrode for the detection of dopamine (DA) and uric acid (UA).