毛细管电泳安培检测扑热息痛及其水解物

研究了各种电化学预处理条件下碳纤维电极对扑热息痛及水解物的电化学行为。确定该体系最佳预处理条件为０．２Ｖ电位下阳极化１ｍｉｎ，再于－２．０Ｖ下阴极化１０ｓ。预处理后的碳纤维伏安响应得到明显提高。运用最佳条件并在支持电解中加入添加剂后，扑热息痛及其水解物在毛细管电泳上获得很好的分离和检测。其中扑热息痛的检测下限为２．７８ｐｇ；对氨基酚为１．８４ｐｇ。     

Increase of Calcium Levels at Interphase in NIH 3T3 Cells

The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca~(2+)]_i) and the DNA content of individual living NIH3T3 cells. The well-separated excitation and emission properties of these dyes allowed us to establish for each cell both the phase of the cell cycle using DNA content and [Ca~(2+)]_i. We found that the transition from G_1, through S, to the G_2 phase is accompanied by a two-fold increase in [Ca~(2+)]_i. The [Ca~(2+)]_i was inhomologous in each phase of the interphase (G_1, S and G_2) although [Ca~(2+)]_i in the S and G_2 phases was never lower than certain threshold values in the G_1 and S phases respectively. [Ca~(2+)]_i in G_0 cells was lower than that in G_2 cells. These changes in [Ca~(2+)]_i suggest that [Ca~(2+)]_i may be an import regulator of cell cycle progression.     

Immobilization of thiabendazole-specific monoclonal antibodies to silicon substrates via aqueous silanization

Monoclonal antibodies specific for thiabendazole were immobilized to silicon, silicon dioxide, stoichiometric silicon nitride, and silicon-rich silicon nitride surfaces. This work provides the foundation for the development of a homogeneous sensor system for rapid detection and quantification of thiabendazole residues in produce and animal tissue. Immobilization was performed via aqueous silanization of the substrate followed sequentially by treatment with glutaraldehyde and contact with antibody solution in the presence of detergent. Surfaces were challenged with thiabendazole-horseradish peroxidase conjugate in an ELISA format to estimate immobilized antibody load. A stable and reproducible surface loading of 2 x 10¹¹ antibodies/cm² was obtained only after surfaces received postimmobilization treatments to remove nonspecifically adsorbed antibody. No difference in surface loading was noted when using 30% hydrogen peroxide rather than nitric acid for silanol activation. Little difference was noted among the antibody loadings achieved on the various silicon substrates. Bound antigen-enzyme conjugate was eluted with 0.1N acetic acid and reproducible surface activity was measured for up to four consecutive antigen challenges. Immobilized antibody surfaces were stabilized with 2% sucrose, dehydrated at 37‡C and stored in vacuum or stored at 4‡C in phosphate buffered saline containing 0.01% sodium azide without significant loss of activity.     

过氧化物模拟酶在介体型生物传感器方面应用初探

meso-四(4-磺基苯)卟啉锰(Ⅲ)作为过氧化物模拟酶可催化H_2O_2与K_4Fe(CN)_6反应。电流响应与H_2O_2浓度在3.0×10~(-4)～1.0×10~(-3)mol/L范围内呈线性关系。重现性和回收率良好。抗坏血酸和DL-半胱氨酸干扰严重。     

石英晶体微天平技术研究纳米TiO_2表面Cu(Ⅱ)吸附与光化学还原过程

环境中排放的重金属离子Cu!对水生和陆生生物有强的毒害性。饮用水中Cu!的浓度高于1.0mg·L-1时,将会导致人畜得血色沉着病和胃肠粘膜病[1]。Cu!无法进行生物降解,除去废水中Cu!的常见方法有离子交换、置换、化学沉淀等[2],然而这些方法需要消耗大量的化学试剂,成本高。近来,研     

二氧化碳与丙烯直接合成甲基丙烯酸用CuPMo／TiO2催化剂的研究

 用溶胶－凝胶法以磷钼酸（MPA）的铜盐溶液水解钛酸四丁酯制备了CuPMo／TiO2催化剂，并用ICP，XRD，TG－DTA，IR，TPD－MS和微反技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化性能．结果表明：杂多钼酸盐与TiO2表面通过O2－桥发生键联．在623K下，杂多阴离子仍保持其原有的Keggin结构；CO2在Lewis酸位Cu（Ⅱ）和Lewis碱位Cu－O－Mo桥氧的协同作用下形成卧式吸附态Cu（Ⅱ）←O－（CO）←（O－－Cu）；丙烯以分子吸附态在催化剂上吸附；在空速1500h－1，压力1MPa和温度563K的反应条件下，丙烯的转化率为4．2％，甲基丙烯酸的选择性为96％．     

裸玻碳电极伏安测定甲氰咪胍

提出了裸ＧＣＥ不需任何处理测定甲氰咪胍的方法，浓度在３×１０＾－７－６×１０＾－５ｇ／ｍＬ，范围内与峰电流呈线性关系，ＲＳＤ为２．２％，回收率为９６％－１０２％。该方法操作简便快速，大多数金属离子和多种有机生化物质不干扰测定，方法用于片剂和加标尿样中甲氰咪胍的测定与药典方法对照，获得满意结果，并对电极反应进行了初步探讨。     

Temperature Development of Homo- and Hetero-Clustering in Saturated Vapors

Computational findings of temperature increase of clustering degree in saturated vapors are analyzed. A thermodynamic proof is presented and a simple criterion derived. Illustrations are based on saturated steam, magnesium and carbon vapor. The results are applicable to synthesis of fullerenes, metallofullerenes, and heterofullerenes, chemical vapor deposition technique, or atmospheric chemistry.     

ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au^3+

Organic chelating reagent influences upon the redox adsorption of activated carbon fibertowards Au3- were systematically investigated. The experimental results indicated that the presenceof organic chelating reagent on activated carbon fiber strongly affects adsorption capacity ofactivated carbon fiber towards Au3+. The reduction-adsorption amount of Au3+ increased three timesby the presence of 8-quinolinol. Furthermore, The reduction-adsorption amount of Au3+ depended onthe pH value of adsorption and temperature.