FSCV signals
in the absence of analytes and during ionic concentration
changes in phosphate-buffered saline. (A) Total background currents
for as-prepared carbon fiber microelectrodes (black) and after electrochemical
conditioning for 3 and 6 min (green and orange, respectively). Arrows
indicate the location of the peaks referenced in the text. (B) Background-subtracted
CV (−0.4–1.0 V vs Ag/AgCl, 400 V/s, 10 Hz) for acidic
pH shift (−0.15 pH units from pH 7.4) (C) Adsorption curves
(2.5–100 mM, top) at each conditioning time point and representative
background-subtracted CV (100 mM, bottom) for potassium injections.
(D) Adsorption curves (0.025–1.0 mM, top) at each oxidation
time point and representative background-subtracted CV (1.0 mM, bottom)
for magnesium injections.