An Electrochemical Sensor for Determination of Bisphenol A Based on Reduced Graphene/Silver Nanoparticles Composites / 分析化学

Graphene and silver nanoparticles showed good application potentials in electrochemistry due to their unique folded layered structure and good catalytic performance. In this work, reduced graphene oxide-Ag nanoparticles ( rGO/AgNPs ) composite material was prepared in situ by using hydrothermal reduction synthesis method with sodium citrate as reducing agent. The material was then used as modified electrodes to study the electrochemical behaviors of bisphenol A ( BPA) . The results of cyclic voltammetry and square wave voltammetry showed that the fast oxidation-reduction reaction of BPA could occur on the rGO/AgNPs modified glassy carbon electrode and lead to the sensitive determination of BPA. Under the optimal conditions, the oxidation current of BPA was linear to its concentration in the range of 0 . 1-40 . 0 μmol/L and the detection limit was 50 . 7 nmol/L ( S/N=3 ) . The presented method was also used for the determination of BPA in plastic samples with satisfactory results.

Rapid Identification of Alcohol Compounds by Cyclic Chemiluminescence / 分析化学

Rapid discrimination of compounds with similar structures and properties is a hot topic in analytical chemistry. In this study, a cyclic chemiluminescence (CCL) system was designed by using nano-magnesium oxide as catalyst. The effects of reactant concentration, reaction temperature and detection wavelength on CCL analysis were studied. It was found that the CCL signal satisfied the first order exponential decay law. Each reaction had an exponential decay equation (EDE) describing its signal change law. The initial variable A was proportional to the reactant concentration. The decay-coefficient k was a characteristic constant that was independent of the reactant concentration. For iso-butanol, it's A-values versus concentration was linear in 0. 89-14. 24 mg / L, the average of k-value in this range was 32. 0 with a RSD of 2. 2% . Thus, qualitative and quantitative analysis could be conducted according to the A and k values. The system was used to analyze eight kinds of alcohol compounds, and it was found that there were significant differences in the k-values for different alcohols. For example, the k-values for n-butanol, iso-butanol and sec-butanol were 27. 2 ±0. 2, 32. 0±0. 8 and 19. 5±0. 1, respectively.