Electrochemical ds-DNA-Based Biosensor Decorated with Chitosan Modified Multiwall Carbon Nanotubes for Phenazopyridine Biodetection, 341. Ali A. Ensafi, Somayeh Lesani, Maryam Amini, B. Rezaei, , Journal of the Taiwan Institute of Chemical Engineers, 201
A simple and inexpensive method was used to develop a novel electrochemical sensor for the determination
of phenazopyridine hydrochloride (PAP). Differential pulse voltammetry was used for the electrochemical
investigation of the interaction of PAP with calf thymus ds-DNA at a pencil graphite electrode (PGE) based
on the reduced oxidation signals of guanine and adenine. The biosensor was constructed using pretreated
pencil graphite electrode (PGE) modiﬁed with multiwall carbon nanotubes (MWCNTs) and chitosan (CHIT)
decoratedwithds-DNA.Thereductionsintheintensities ofguanineandadenineoxidationsignals aftertheir
between adenine and guanine oxidation signals (of the ds-DNA) before and after their interaction with PAP
were found to be directly proportional to PAP concentration, which was used for quantitative inspections.
Under optimum conditions, a linear dependency was observed between guanine and adenine oxidation
signals and PAP concentration in the range of 0.01–50 μ g/mL with a detection limit of 0.003 μ g/mL. The
method was also found to be highly selective and was successfully employed for the determination of PAP in
real samples such as human plasma and urine.