biostudies-literatureSekar SNational Research Foundation (NRF) of KoreaKorean government (MSIT)Ministry of Education of korea124https://www.ebi.ac.uk/biostudies/studies/S-EPMC12937753biostudies-literatureUnknown16(2)We report a highly sensitive and interference-free electrochemical sensor for dopamine (DA) detection in the presence of uric acid (UA) and ascorbic acid (AA), based on an in situ deposited graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) and polymethyl thymol blue (PMTB) nanohybrid modified screen-printed carbon electrode (SPCE). The as-fabricated g-C<sub>3</sub>N<sub>4</sub>/PMTB/SPCE was thoroughly characterized using various physicochemical techniques. The electrochemical behavior of the modified electrode was systematically investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The g-C<sub>3</sub>N<sub>4</sub>/PMTB/SPCE exhibited excellent electrocatalytic activity toward the selective oxidation of DA under optimized experimental conditions, includingBiosensorsMetal-Free Electrochemical Dopamine Sensing Using a g-C<sub>3</sub>N<sub>4</sub>/Polymethyl Thymol Blue Nanohybrid.PMC12937753RS2023002497782021R1I1A1A01049638; RS-2023-NR076644, RS-2022-NR075805RS-2021-NR060086Lee SChang SCSelvan KSSadhasivam SIlanchezhiyan PLee YSekar SManikandan RfalseMetal-Free Electrochemical Dopamine Sensing Using a g-C<sub>3</sub>N<sub>4</sub>/Polymethyl Thymol Blue Nanohybrid.We report a highly sensitive and interference-free electrochemical sensor for dopamine (DA) detection in the presence of uric acid (UA) and ascorbic acid (AA), based on an in situ deposited graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) and polymethyl thymol blue (PMTB) nanohybrid modified screen-printed carbon electrode (SPCE). The as-fabricated g-C<sub>3</sub>N<sub>4</sub>/PMTB/SPCE was thoroughly characterized using various physicochemical techniques. The electrochemical behavior of the modified electrode was systematically investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The g-C<sub>3</sub>N<sub>4</sub>/PMTB/SPCE exhibited excellent electrocatalytic activity toward the selective oxidation of DA under optimized experimental conditions, including2026-01-01T00:00:00Z2026 Feb2026-07-11T03:15:12.591Z2026-07-11T03:11:48.513ZS-EPMC129377534174474210.3390/bios16020124