Background:
L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly
present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger
of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to
its role in the biological metabolism, AA has also been utilized for the therapy of mental illness,
common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop
a simple, rapid and selective strategy for the detection of AA in various samples.
Methods:
The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the
analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes
(MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine
(oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were
optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic
voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of
the imprinted polymer film.
Results:
Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct
linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations
of AA, and the detection limit was 2 nmol L-1 (S/N=3).
Conclusion:
The proposed electrochemical sensor possesses excellent selectivity for AA, along with
good reproducibility and stability. The results obtained from the analysis of AA in real samples
demonstrated the applicability of the proposed sensor to practical analysis.
A pH-dependent structural transition in the homopurine-homopyrimidine tract in superhelical DNA