2.2.4. Electrochemical measurements
The electrochemical measurements was performed using a CS120
electrochemical work station (CorrTest, China). A three-electrode system
was used for the measurement, where a gold disc electrode (d=3.0 mm,
Tianjin Aida, China; the same brand for other electrodes below) was used
as the working electrode, an Ag/AgCl (saturated KCl,
Eo = 0.190 V vs. standard hydrogen electrode) was used
as the reference electrode and a platinum sheet as the counter
electrode. The electrodes were inserted into a solution of D.r.bacteria (with a concentration of 2×108mL-1) which was directly taken from the incubation
mixture with the PYG broth. Next, anodic stripping voltammetry was
applied every 1.5 hours to monitor the silver ion concentration of the
bulk solution within a total period of 9 hours. Specifically, the
stripping voltammetry was conducted by applying in sequence a
surface-refreshing potential of 0.6 V vs. Ag/AgCl for 60 seconds, a
pre-concentration potential of -0.45 V for 60 seconds again, and a
potential cycle between 0.0 and 0.6 V at a scan rate of 0.1 V
s-1.