According to the optimum conditions, differential pulse voltammograms
were recorded for BPR determination. As can be seen from
Fig. 4A, the DPV signal was enhanced along with the increasing
concentration of BPR. Fig. 4B demonstrates the linear relationship
between concentrations of BPR and the DPV current responses of the
electrode in the presence of 0.24 mM SDS under the optimized instrument
parameters and experimental conditions. The peak current increased
linearly against the concentration of BPR on the two ranging
from 4.00 nM to 0.126 μM (R2 = 0.9985) and from 0.126 to 0.317 μM
(R2 = 0.9560). The detection limit for BPR was calculated to be 1.33 nM
based on S/N = 3. A low detection limit and wide linear range were
obtained at CPE in the presence of SDS compared to the other reports
(Table 2).