Fabrication of an Amperometric Flow-Injection Microfluidic Biosensor Based on Laccase for In Situ Determination of Phenolic Compounds

Figure 2

Nyquist plots (a) and cyclic voltammograms (b) at bare electrode (gray) and laccase modified Au electrode sealed in the fluidic microsystem (black). Continuous lines represent results from data fitting. Inset is the equivalent circuit. Solution: 1 mM K₄[Fe(CN)₆] + K₃[Fe(CN)₆] + 0.1 M phosphate buffer (pH. 7.0). For EIS, a sinusoidal potential modulation of ±5 mV was superimposed on the DC potential of 0.2 V versus Ag/AgCl/KCl_3M. Applied frequency was from 10⁶ to 0.1 Hz. For CV the scan rate was 100 mV s⁻¹.

(a)

(b)