A facile poly(allura red) film for signal-amplified electrochemical sensing of dopamine and uric acid in human plasma and urine

A novel and facile sensing platform based on poly(allura red) film, synthesized via a one-step cyclic voltammetry scanning, was used for determining dopamine and uric acid in human plasma and urine. The signal was amplified thanks to the good pi-pi and electrostatic interaction of the allura red polymer film, and thus the superior electron transfer rate. The electrochemical determination of dopamine and uric acid, alone and in the presence of each other, was investigated and the oxidation peaks at 190 mV for dopamine and 320 mV for uric acid were used as the analytical response. Characterization measurements for the fabricated platform were performed with various techniques including cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron micro-scopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The poly(allura red) film-modified electrode exhibits a remarkable limit of detection values of 10.5 nM for dopamine and 30.1 nM for uric acid with wide linear ranges of 0.03-20 mu M and 25-70 mu M mu M for dopamine, 0.09-110 mu M for uric acid, 0.48-80 mu M and 90-290 mu M for dopamine in the presence of uric acid, and 0.35-200 mu M for uric acid in the presence of dopamine. The proposed method was applied to the human plasma and urine samples, the results were statistically compared with those obtained from the titrimetric method, and no significant difference at a 95 % confidence level was found.