Poly (Rhodamine B) and MWCNTs Composite Film for the Separation and Simultaneous Voltammetric Quantification of Tryptophan, Paracetamol, Uric Acid, Dopamine and Ascorbic Acid

This paper focuses the separation and voltammetric quantification of five significant compounds, such as tryptophan (Trp), paracetamol (APAP), uric acid (UAC), dopamine (DA) and ascorbic acid (AA), which may coexist in urine samples. The poly (Rhodamine B) / MWCNTs composite film was created on glassy carbon electrode by cyclic voltammetric technique. Electroanalytical behaviors of analytes at poly (Rhodamine B)/ MWCNTs/GC electrode were examined using both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Electrochemical impedance (EIS) and scanning electron microscopy (SEM) were employed to characterize the dielectric properties and morphology of the composites. The linear working ranges for simultaneous estimation of Trp, APAP, UAC, DA and AA were 2.0–100 μM, 3.0–70 μM, 2.0–100 μM, 0.5–20 μM, and 200–5000 μM, respectively and the detection limits were 0.25 μM, 0.65 μM, 0.54 μM, 0.05 μM, and 20 μM, respectively. The developed sensor was set up to be suitable for the routine analysis of the Trp, APAP, UAC, DA and AA in the urine and pharmaceutical samples and satisfactory results were received. Moreover, the sensor was applied for the quantification of p-aminophenol (PAP) in the presence of Trp, APAP, UAC, DA and AA. Well-separated oxidation peak currents were observed in phosphate buffer solution at pH 7.0. Keywords: Ascorbic acid, dopamine, Multi-walled carbon nanotubes, p-aminophenol, paracetamol, Rhodamine B, tryptophan, uric acid, voltammetry.