FIG. 2.
Representative Bode plots obtained after 5 days of static incubation for the wild type, the fliI and menC mutants, and an uninoculated control. The curves represent independent EIS runs for parallel cultures. Symbols: ◊, wild type; ★, fliI mutant; ▵, menC mutant; +, uninoculated control. The logarithm of the impedance modulus (|Z|) is plotted versus the logarithm of the frequency (f) of the applied alternating current signal. When the frequency of the applied signal was very low (f → 0, left side of the spectrum), impedance recordings reflected the Rp at the surface of the test electrode (in this case, 1018 steel). When the frequency was very high (right side of the spectrum), impedance recordings reflected the electrolyte resistance in solution. Rp is inversely proportional to the corrosion rate.