味觉电化学传感器的研究——Ⅰ.甜、酸、苦、咸物质对模拟生物膜电位振动频率的影响

本文以十六烷基三甲基溴化铵/含苦味酸的硝基苯/蔗糖溶液为研究体系,发现甜、酸、苦、咸物质均能使体系的振动波形和频率发生变化,初步建立了测定有味物质的定性、定量方法,并对该味觉电化学传感器的响应机理进行了探讨。     

Nafion化学修饰圆盘预富集-石墨炉 原子吸收联用法对牛血超氧化物歧化酶中铜、锌分布状态的研究

本文研究了Nafion化学修饰钨丝圆盘预富集-石墨炉原子吸收(GFAAS)方法测定牛血超氧化物歧化酶(SOD)中游离态Cu～(2+)及Zn～(2+)的方法,并用GFAAS法直接测定SOD中铜、锌的总量,证实了牛血SOD中金属辅基铜、锌原子个数比为1:1,初步探讨了一定浓度的牛血SOD中Cu～(2+)、Zn～(2+)的表观离解平衡常数。为提高SOD的活性和稳定性的研究,提供了一种有效的方法。     

Determination of drug-protein interactions by microdialysis coupled with liquid chromatography and electrochemical detection based on a nickel hexacyanoferrate modified electrode

Microdialysis sampling coupled with liquid chromatography-electrochemical detection (LC-ED) was developed and applied to determine the interaction of thiopurine (TP) with bovine serum albumin (BSA). A nickel hexacyanoferrate (NiHCNFe) modified electrode was fabricated and used as the working electrode in LC-ED for the determination of TP. Cyclic voltammetric experiments demonstrate that this chemically modified electrode (CME) can effectively catalyze the electrooxidation of TP. The mechanism of the catalytic oxidation of TP at the CME involves an 'EC' process. In the LC-ED, the CME also shows good stability and reproducibility for the determination of TP. The limit of detection is 5.0 x 10(-7) mol l(-1) for 6-TP with a signal-to-noise ratio of 3. The utility of microdialysis as a quantitative sampling technique for in vitro studies of drug-protein interactions was studied. The microdialysis experiments were performed in phosphate buffer solution (pH 7.4) containing different molar ratios of the drug and protein at 37 degrees C. The collected microdialysis sample with unbound TP was analyzed at the NiHCNFe CME in the LC-ED. The relative recovery of TP determined in vitro is 18.3% at a perfusion rate of 1.0 microl min(-1) and the RSD is about 2.1%. The association constant and the number of binding sites on a BSA molecule calculated with the Scatchard equation are 3.72 x 10(-3) (1 mol(-1)) and 1.51, respectively. This method provides a fast, sensitive and simple technique for the study of drug-protein interactions.     

The study of nafion/xanthine oxidase/au colloid chemically modified biosensor and its application in the determination of hypoxanthine in myocardial cells in vivo

A novel hypoxanthine (Hx) microsensor was constructed. In this work, Nafion xanthine oxidase (XOD) and Au colloid were immobilized onto the surface of a Pt microelectrode. The enzyme biosensor displayed a quick and sensitive response to Hx. Under physiological conditions, a low detection limit, with high selectivity and sensitivity for Hx determination were obtained. The oxidation current [investigated using current-time (I-t) plots] was linear with Hx concentration ranging from 2.0 x 10(-7) to 2.0 x 10(-5) mol L(-1) with a calculated detection limit of 1.0 x 10(-7) mol L(-1) (S/N of 3). The biosensor should be promising for in vivo measurement of Hx without interferences and fouling. The change of Hx concentration in cardiac myocytes stimulated by L-arginine (L-Arg) and acetylcholine (Ach) was also studied.     

FDU-15-Pt composites with different Pt loading and their electrocatalytic reduction to ultratrace nitroaromatic compounds

FDU-15 is a hexagonal mesoporous material with nanometer-sized, highly ordered arrays and large special surface area. In this work, FDU-15-Pt with 2.0%, 5.0% and 8.0% Pt loading were synthesised and used for electrochemical detection of trace nitroaromatic compounds (NACs). The FDU-15-Pt samples were characterised by CO Chemisorption, transmission electron microscopy (TEM) and X-ray diffraction (XRD). It has been demonstrated that FDU-15-Pt with 2.0% Pt loading has the smallest Pt particle size of 2.9?nm, highest Pt metal dispersion of 37.7% and largest Pt metal surface area of 21.36?m^2?g^?1. The FDU-15-Pt/PDDA modified electrode were assembled by electrostatic adsorption of Poly (diallyldimethylammonium chloride) (PDDA) and FDU-15-Pt. The 2.0% FDU-15-Pt modified sensor showed higher selectivity for NACs than those of 5.0% and 8.0% FDU-15-Pt, which were verified by electrochemical experiments. A linear response over TNT concentration ranging from 8.8?×?10^?9?M to 1.2?×?10^?5 M was exhibited with a low detection limit of 2.9?×?10^?9?M (S/N?=?3). Moreover, the proposed 2.0% FDU-15-Pt/PDDA modified sensor has been applied to the detection of NACs in spiked environmental water samples and shows promise for fast and accurate determination of trace NACs in real samples.     

Catalytic properties of mesoporous materials supported heteropoly acids for Baeyer-Villiger oxidation of cyclic ketones

Three mesoporous molecular sieves loaded silicotungstic acids, named HSiW/SBA-15, HSiW/MCM-41, HSiW/MCM-48, were prepared and characterised by XRD, FT-IR, TEM and SEM. The catalytic performance of the prepared materials for the Baeyer-Villiger oxidation of cyclic ketones was carried out in the presence of 30%H₂O₂ under mild conditions. These loading materials were proved to be efficient and reusable catalysts, they all exhibited excellent catalytic performance for the Baeyer-Villiger oxidation of cyclic ketones with 30% H₂O₂ as oxidant. Many cyclic ketones were efficiently converted to the corresponding lactones with up to 90% conversions and high selectivities under the optimum reaction conditions.

Cyclic ketones were efficiently oxidised by mesoporous materials sopported silicotungstic acid to the corresponding lactones with 30%H₂O₂ as oxidant. All of the catalysts showed promising recyclability in the reactions.     

聚N,N-双水杨醛乙二胺合钴修饰超微电极的制备及其在一氧化氮测定中应用的研究

通过电化学聚合法制备了聚Ｎ，Ｎ－双水杨醛乙二胺合钴［ｐｏｌｙＣｏ（Ｓａｌｅｎ）］修饰超微电极，研究了该修饰电极的电催化性质及其在一氧化氮（ＮＯ）测定中的应用．实验结果表明，ｐｏｌｙＣｏ（Ｓａｌｅｎ）修饰超微电极对ＮＯ的测定有高的灵敏度，ＮＯ的浓度在２．０×１０－８～２．８×１０－６ｍｏｌ／Ｌ范围内，电流与浓度呈良好的线性关系，线性相关系数为０．９９９８，检出限为１．０×１０－８ｍｏｌ／Ｌ；该电极进一步修饰Ｎａｆｉｏｎ后，生物体中常见的物质如抗坏血酸、儿茶酚胺类神经递质的代谢物、ＮＯ的氧化产物ＮＯ－２等不干扰测定．本传感器可以满足ＮＯ在体分析的需要．     

论连通图的可重构性

本文我们利用带权核子图的可重构性证明了连通图是可重构的,从而证明了重构猜想为真.