Fig. 3

Comparison of the voltammetric response recorded before and after the alkaline pretreatment of CFMEs for 1 μM dopamine, epinephrine, norepinephrine, serotonin, and ascorbate. The signal shown is the average response measured for each analyte by DPV (4 mV potential increment, 50 mV pulse amplitude, 50 ms pulse width, and 200 ms pulse period). Ascorbate was not detected within the used potential window. The error bars represent the standard error of the mean for “n” replicate experiments. Statistical significance between the two groups is calculated using the one-way ANOVA with the post-hoc Tukey HSD test and it is indicated by one (*) and two (**) asterisks at p < 0.05 and p < 0.01, respectively, or by “ns” for no statistical significance.