Hu Xiaoya

Electrochemical determination of purine and pyrimidine DNA bases based on the recognition properties of azocalix[4]arene.

The azocalix[4]arene film modified glassy carbon electrode was established for the convenient and sensitive detection of four DNA bases (guanine, adenine, thymine and cytosine). Field emission scanning electron microscopy, attenuated total reflectance-FTIR and X-ray photoelectron spectroscopy were used to characterize the film. The azocalix[4]arene film exhibited excellent electrocatalytic activity toward the oxidation of all bases. Well-separated voltammetric peaks were obtained among guanine, adenine, thymine and cytosine, which lead to the feasibility for the simultaneous determination of all of them in a mixture without separation or pretreatment. Linear calibration curves were obtained from 0.125 to 200.0 μM for adenine, 0.125 to 175.0 μM for guanine, 2.50 to 650.0 μM for thymine, and 2.50 to 650.0 μM for cytosine. This sensor also exhibits good stability, reproducibility and long lifetime.

Sodium dodecyl sulfate sensitized electrochemical method for sub-picomole level determination of topotecan hydrochloride at a novel disposable electrode

A sub-picomole level topotecan hydrochloride determination method was first proposed using sodium dodecyl sulfate (SDS) as a sensitized reagent at a novel disposable electrode (an improved wax-impregnated graphite electrode). The effects of different kinds of surfactants on the electrochemical response to topotecan hydrochloride were examined. The results indicate the electrochemical signal was apparently improved by SDS. At optimal conditions, the oxidative peak current increased linearly with the logarithm of concentrations for topotecan hydrochloride in the ranges of 2.0 × 10−12 to 1.0 × 10−11 mol/L and 8.0 × 10−11 to 8.0 × 10−10 mol/L with a detection limit of 6.4 × 10−13 mol/L. The proposed method could be applied in determining topotecan hydrochloride in urine.

电致化学发光法测定Mn 2+ 含量的研究

在H 3 PO 4 溶液中，利用Ag + 存在条件下，Mn 2+ 可以被电化学氧化成KMnO 4 ，KMnO 4 进而与酸性邻苯二酚或碱性鲁米诺等发生反应，得到较好的化学发光信号，构建了一种间接测定水溶液中Mn 2+ 含量的方法。研究了Ag + 对Mn 2+ 电化学氧化的影响。Mn 2+ 电化学氧化过程中，当Ag + 浓度为1.5×10 -5 mol/L，H 3 PO 4 浓度为0.01 mol/L，电解2 min后，发光强度达到最大。探讨了不同pH条件下的化学发光强度与Mn 2+ 浓度的关系及选择性。在酸性介质中，邻苯二酚的发光强度与Mn 2+ 在1.82×10 -7 -7.27×10 -5 mol/L的浓度范围内呈现良好的线性关系；常见的金属离子等对Mn 2+ 测定干扰小。将本方法用于地表水及饮用水中Mn 2+ 的测定，与标准方法相比，结果令人满意。

A new method of preparing alkanethiol-protected gold nanoparticals

In a new two-phase system (tetrahydrofuran/saturated NaCl aqueous solution) monolayer protected clusters (MPCs) were prepared. The AuCl4− anion in saturated electrolyte aqueous solution was transferred into the organic phase of tetrahydrofuran by tetra-n-butylammonium bromide ((C4H9)4NBr) and was reduced quickly by sodium borohydride in the presence of alkanethiol. The functionalized MPCs were characterized by solubility, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray (EDX) analysis and UV-vis spectroscopy. Electrochemical measurements of MPCs in CH2 Cl2 exhibited 7 pairs of reversible voltammetric waves within the potential range of −1.0 to 1.0V (vs Ag/AgCl), which was ascribed to the quantized capacitance charging of nanoparticle double layers. All the results show that the new preparing method is feasible.