A poly(trypan blue)-Modified anodized glassy carbon electrode for the sensitive detection of dopamine in the presence of uric acid and ascorbic acid

A conducting polymeric film of trypan blue (TB) was deposited onto an anodized glassy carbon electrode (AGCE) surface by electropolymerization. The poly(trypan blue)-modified AGCE was used for the determination of dopamine (DA) in the presence of uric acid (UA) and ascorbic acid (AA). The PTB/AGCE exhibits good electrocatalytic behavior for the oxidation of DA in phosphate buffer solution (PBS, pH 7.0). The electrochemical oxidation signals of DA, UA, and AA are well-resolved into three distinct peaks in cyclic voltammograms (CVs) with the anodic peak potential separations (δEpa) of ca. 186, 145, and 331 mV between AA-DA, DA-UA, and AA-UA, respectively. The δ Epa values are large enough to discriminate DA from the interference of AA and UA. A detection limit of ca. 0.36 μM (S/N = 3) was obtained for the sensing of DA with a linear range of 1-40 μM in PBS (pH 7.0). The sensor could successfully determine the concentrations of DA in human urine samples with the recoveries of ca. 97.6-102.6%. This approach provides a simple, easy, sensitive, and selective method for the detection of DA in the presence of AA and UA.