A Dopamine Sensor Based on Pre-Concentration by Magnetic Nanoparticles

Figure 8

The square wave voltammograms obtained on the MCPE/MNP in PBS, DA free, pH 7.0, and 0.1 M NaClO₄ after 20 min pre-concentration in PBS (pH 7.0) containing 1.0×10⁻³ M AA and different concentrations of DA; bottom to top: 0.0, 5.0×10⁻⁶, 1.0×10⁻⁵, 2.0×10⁻⁵, 5.0×10⁻⁵, 1.0×10⁻⁴, 2.0×10⁻⁴, 4.0×10⁻⁴, 5.0×10⁻⁴, and 1.0×10⁻³ M DA. SWV conditions were as; pulse height (10 mV), square wave amplitude (50 mV), and square wave frequency (40 Hz). Inset is calibration curve {(𝑖_p−𝑖_pb)/𝜇A=100.1(±1.123)/𝜇A+18.62(±0.271)log([DA]/M), 𝑟²=0.999} obtained from variation of the SWV anodic peak current as a function of DA concentration. (𝑖_pb; anodic peak current of blank).