Curcumin-functionalized nanocomposite AgNPs/SDS/MWCNTs for electrocatalytic simultaneous determination of dopamine, uric acid, and guanine in co-existence of ascorbic acid by glassy carbon electrode

Abstract

The binding of curcumin on the surface of AgNPs-sodium dodecyl sulfate (SDS)-multi-walled carbon nanotubes–glassy carbon electrode (CM/AgNPs/SDS/MWCNTs) was reported for simultaneous electrochemical determination of dopamine (DA), uric acid (UA) and guanine (GU). Morphological properties of modified electrodes surfaces were characterized using different voltammetry methods. The microscopic area of the modified electrode was obtained 0.139 cm⁻² using chronoamperometry analysis. The scanning electron microscope (SEM), XRD, and TEM were used to monitor the sensor fabrication. The zeta potential results showed that SDS dispersed the pure AgNPs, and the AgNPs were significantly stabilized. Also, the results showed that the constructed CM-functionalized nanocomposite create a large surface area, long stability, good adaptability, anti-interference capability, and significant reproducibility. The electrochemical results confirmed that the fabricated nanocomposite has a high electrocatalytic activity toward the oxidation of analytes especially for DA (vs. Ag/AgCl). While the above results hold true for DA, UA, and guanine GU determination, there was no comparable electrochemical peak for ascorbic acid (AA). The calibration curves were linear in the range of 12.0–200.0, 16.0–400.0, and 18–650.0 μmol L⁻¹ for DA, GU, and UA, respectively. The detection limit values were 0.14 μmol L⁻¹ for DA, 0.19 μmol L⁻¹ for GU, and 0.38 μmolL⁻¹ for UA. The prepared electrode was applied successfully to the simultaneous determination of analytes in blood, serum, urine, and dopadic ampoule samples.