An 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)-immobilized electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

An 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS)-immobilized carbon nanotube (CNT) electrode was used to simultaneously detect dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) with differential pulse voltammetry. When ABTS was immobilized onto the CNT electrode in the presence of DA, UA and 100 μM AA, the sensitivity to DA increased from 0.600 (± 0.013) to 1.334 (± 0.010) μA/μM in the concentration ranges of 0.90–10 μM and 1.87–20 μM, respectively, and the sensitivity to UA increased from 0.030 (± 0.005) to 0.078 (± 0.006) μA/μM in the concentration ranges of 2.16–240 μM and 3.07–400 μM, respectively. These findings demonstrate that the ABTS-immobilized CNT electrode attained a higher sensitivity to UA and also a wider linear range of concentrations.

► ABTS, as a mediator, improved electrode activity for DA and UA. ► The peaks became sharper for DA and UA with ABTS-modified electrode. ► The ABTS electrode simultaneously detected DA and UA with good peak separation. ► The sensitivities increased 1.2 and 1.6 times for DA and UA, respectively. ► The modified electrode had higher sensitivity and larger linear concentration ranges.