Yan-Li Liu

Nano-ZnO/Chitosan Composite Film Modified Electrode for Voltammetric Detection of DNA Hybridization

Abstract A sensitive electrochemical DNA biosensor based on nano-ZnO/chitosan composite matrix for DNA hybridization detection was developed. The Nano-ZnO was synthesized by the hydrothermal method and dispersed in chitosan, which was used to fabricate the modification of the glassy carbon electrode (GCE) surface. The ZnO/chitosan-modified electrode exhibited good biocompatibility and excellent electrochemical conductivity. The hybridization detection was monitored with differential pulse voltammetry (DPV) measurement using methylene blue (MB) as an indicator. The established biosensor can effectively discriminate complementary target sequence and two-base-mismatched sequence, with a detection limit of 1.09 × 10−11 mol L−1 of complementary target.

Highly Selective Dopamine Determination by Using Carboxymethylated β‐Cyclodextrin Polymer Film Modified Electrode

Abstract A highly selective and sensitive electrochemical sensor modified with carboxymethylated β‐cyclodextrin (CM‐β‐CDP) polymer film was fabricated for the determination of dopamine (DA) in the presence of ascorbic acid (AA). The electrochemical behavior of DA and AA at the chemically modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry. The response mechanism of CM‐β‐CDP film for DA was based on the combination of electrostatic and inclusion interaction of CM‐β‐CDP for DA, which was distinguished from the response mechanism of the charged polymer film modified electrode that only relied upon the electrostatic interaction between charged polymer film and DA (or AA) to realize the separation of overlapping peak potential of DA and AA. The CM‐β‐CDP film showed preferable analytical performance characteristics in catalytic oxidation of DA compared with the β‐CDP polymer film. Under optimized conditions, it was feasible for the electrode modified with the CM‐β‐CDP film to selectively determine DA in the presence of a large excess of AA. A linear calibration plot was obtained over the range 0.8–60 µM with a sensitivity of 65 nA/µM and a detection limit (signal/noise (S/N) = 3) of 0.2 µM in the presence of 1.0 mM AA. This electrochemical sensor showed excellent sensitivity, repeatability, stability, and recovery for the determination of DA. The interference of AA with the determination of DA could be efficiently eliminated.

Investigation of CdO hexagonal nanoflakes synthesized by a hydrothermal method for liquefied petroleum gas detection

Cadmium oxide (CdO) hexagonal nanoflakes, demonstrated clearly in an SEM image, were synthesized via a one-step hydrothermal method. The formation of CdO was confirmed by XRD spectra and EDS spectra obtained from CdO nanoflakes. To demonstrate the potential applications, a gas sensor was fabricated and a gas sensing test showed that the sensor exhibited significantly high response to liquefied petroleum gas (LPG) with a short response/recovery time. The enhancement of sensing performance was attributed to the unique structure and greater number of surface active sites on the surface of the as-prepared gas-sensing material, which provided increased contact surface area between CdO and gas analytes.