Electropolymerization of Thin Film Conducting Polymer and Its Application for Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid

Gold nanoparticle decorated polypyrrole/graphene oxide nanosheets as a modified electrode for simultaneous determination of ascorbic acid, dopamine and uric acid

AuNPs, GO and PPy are combined effectively to form a novel composite showing a huge enhancement in electrochemical performance compared to the single materials.

Optical properties of folic acid in phosphate buffer solutions: the influence of pH and UV irradiation on the UV-VIS absorption spectra and photoluminescence

Using UV-VIS absorption spectroscopy, photoluminescence (PL) and photoluminescence excitation (PLE), the photodegradation reactions of folic acid (FA) in phosphate buffer (PB) solutions were studied. Regardless of the PB solution's pH, the UV-VIS spectra showed a gradual decrease in absorbance at 284 nm simultaneous with an increase in the absorbance of another band in the spectral range of 320-380 nm, which was downshifted under UV irradiation. The relative intensity of the FA PL band, situated in the spectral range 375-600 nm, was dependent on the pH of the PB solution. The FA PL intensity increased as increasing UV irradiation time up to 281 min. in PB solutions with pH values of 6.4 and 5.4. Under an emission wavelength of 500 nm, the position of the FA PLE spectrum changed as the PB solution pH varied from 7 to 5.4 and the irradiation time increased to 317 min. These changes were correlated with the formation of two photodegradation products, namely, pterine-6-carboxylic acid and p-amino-benzoyl-L-glutamic acid. According to UV-VIS spectroscopy and PL and PLE studies, the presence of various excipients in commercial pharmaceutical tablets does not affect the photodegradation of FA in PB solutions. Using IR spectroscopy, new evidences for the formation of the two photodegradation products of FA in PB solutions are shown.

Electrochemical detection of ractopamine based on a molecularly imprinted poly-o-phenylenediamine/gold nanoparticle–ionic liquid–graphene film modified glass carbon electrode

An electrochemical sensor for sensitive detection of ractopamine (RAC) was fabricated by using molecularly imprinted polymer (MIP) incorporation with graphene (GR), ionic liquid (IL) and gold nanoparticle (AuNPs) nanocomposites.

Surface passivation of titanium dioxide via an electropolymerization method to improve the performance of dye-sensitized solar cells

We introduce an electrochemical method for insulating and passivation open areas of a nanoporous TiO₂ in dye-sensitized solar cells, which can effectively decrease the recombination rate of electrons.

ZnO-CuxO/polypyrrole nanocomposite modified electrode for simultaneous determination of ascorbic acid, dopamine, and uric acid

Novel zinc oxide (ZnO) nanosheets and copper oxide (CuxO, CuO, and Cu2O) decorated polypyrrole (PPy) nanofibers (ZnO-CuxO-PPy) have been successfully fabricated for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The morphology and structure of ZnO-CuxO-PPy nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. Compared with the bare glassy carbon electrode (GCE), PPy/GCE, CuxO-PPy/GCE, and ZnO-PPy/GCE, ZnO-CuxO-PPy/GCE exhibits much higher electrocatalytic activities toward the oxidation of AA, DA, and UA with increasing peak currents and decreasing oxidation overpotentials. Cyclic voltammetry (CV) results show that AA, DA, and UA could be detected selectively and sensitively at ZnO-CuxO-PPy/GCE with peak-to-peak separation of 150 and 154 mV for AA-DA and DA-UA, respectively. The calibration curves for AA, DA, and UA were obtained in the ranges of 0.2 to 1.0 mM, 0.1 to 130.0 μM, and 0.5 to 70.0 μM, respectively. The lowest detection limits (signal/noise=3) were 25.0, 0.04, and 0.2 μM for AA, DA, and UA, respectively. With good selectivity and sensitivity, the current method was applied to the determination of DA in injectable medicine and UA in urine samples.