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.