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Abstract
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polysafranin/multiwall carbon nanotube-Nafion hybrid film was prepared by electropolymerizing safranin on the surface of a
MWCNT-Naf/CPE. The modified electrode was evaluated as an electrochemical sensor for hydrogen peroxide (H2O2) andCu2 in the presence of H2O2, in 0.1 M Tris buffer (pH 6.0) using cyclic and differential pulse voltammetric methods. The electrode
showed a pair of well-defined and quasi-reversible redox peaks with formal potential (E° ) = 0.290 ± 0.005 V versus Ag/AgCl
corresponding to the polysafranin redox couples. The effects of the experimental variables on the electrode behavior regarding
polymerization conditions, electrolyte pH, and MWCNT concentration were investigated to obtain optimum experimental
conditions. The investigation of differential pulse voltammetric results showed that the polysafranin film at the modified
electrode surface acts as an effective catalyst for H2O2 r andCu2 reduction in the presence of H2O2. Under optimum conditions,
the modified electrode exhibited a linear dynamic range of 4.5–23.0 mM and a sensitivity of 17.4 ± 0.4 ?A mM-1 cm?2 toward
H2O2 with a detection limit of 0.6 mM (3Sbl/m). In the presence of 17.0 mMH2O2, the electrode showed a linear response range
of 1.0–80.0 ?Mand a sensitivity of 7.6 ± 0.2 ?A ?M?1 cm?2, with a detection limit of 0.1 ?M (3Sbl/m) for Cu2 . In the next step,
using differential pulse voltammetry, the response of the electrode to Cu2 was studied in the presence of interfering metal ions
that can promote Fenton’s reaction. The results showed that Fe2 , Co2 , andAl3 produce interference atmore than 5-, 2- and 10-
fold ratios ([cation]/[Cu2 ]) respectively.
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