Fig. 2A presents the analytical response obtained to evaluate the deposition
potential for 50 μg L−1 of Mn(II). The studies were conducted
using the interval of 1.0 to 1.4 V, at which the oxidation of Mn2+ to
MnO2 occurs, based on previous works, as described in reaction 1
[15–17,21]. The greatest potential for determination of manganese
was 1.2 V (better signal response) as illustrated in Fig. 2A. The stripping
of Mn(II) occurs in two steps involving the reduction to MnOOH
(reaction 2) followed by further reduction to Mn2+ (reaction 3). In
this work, the first reduction process that occurred at 0.9 V was used
to determine Mn(II). The electrode conditioning was optimized as
−0.5 V for 30 s, which is in agreement with previous works [15–17,
21]. The deposition timewas evaluated based on the analytical response
for 50 μg L−1 of metal. Fig. 2B presents the analytical signal for SWCSV
measurements. The studies were performed in the range of 0 to 300 s.
For further analyses, it was preferred to select 180 s as deposition time
in order to obtain a good correlation between deposition time and
sensitivity without decreasing the analytical frequency method, which
can be estimated in 14 measurements per hour.