极谱过程温度效应的研究(Ⅲ)——催化反应速率常数和反应活化能的测定

催化反应在极谱分析中的应用及反应速率常数的测定已有报道。通常根据Koutecky公式计算催化反应速率常数,而反应活化能则由不同温度下测定的速率常数,按照Arrhenius公式计算。我们根据前文提出的可逆、不可逆、准可逆、动力和催化过程各种极谱电流——温度关系的普遍方程式,测定了Ti(Ⅳ)-H_2SO_4H_2C_2O_4-KClO_3、Mo(Ⅳ)-H_2SO_4-NaNO_3、Mo(Ⅵ)-H_2SO_4-NH_4NO_3体系催化反应速率常数和反应活化能(或表观活化能),结果令人满意。     

Solid-state nanopores for ion and small molecule analysis

Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. This review focuses on the analysis of ions and small molecules with nanopores including nanopipettes, polymer film nanopores, Si₃N₄ nanopores, graphene nanopores, MoS₂ nanopores and MOFs.     

淮山药及其种植土壤中微量元素的测定

用等离子体原子发射光谱(ICP-AES)测定了淮山药根茎及其种植土壤中的微量元素。结果表明,淮山药中含有丰富的人体必需微量元素,为淮山药产品的研究和开发提供重要的依据,也为进一步开发淮山药优良品种和平衡施肥提供科学信息和依据。     

通用型激光诱导荧光微流控芯片分析仪的研制与性能考察

设计和研制了一种通用型激光诱导荧光微流控芯片分析仪.检测部分按共聚焦检测原理设计,采用CCD(电荷耦合器件)监测通道,三维自动调节聚焦,发射波长滤光片可方便地更换以适应多种染料选择,能分别显示进样和分离通道2条电流-时间曲线.考察了该分析仪的检测灵敏度、检测极限和线性范围,显示了分析灵敏度高,检测限低和线性范围宽等特点,在自制注塑型PMMA塑料芯片上实现了φX174Haedi-gesT_dNA片段的分离测定和烟叶act基因PCR产物的分析     

二维DNA晶体的多重熔解过程研究

可人工编程设计的刚性DNA分子瓦(DNA tile)中的DX分子(double-crossover，双交叉)能自组装形成二维DNA晶体。将含有二维DNA晶体的缓冲溶液程序升温，用紫外-可见分光光度计在260 nm处测定二维DNA晶体的熔解曲线，观测到了DNA晶体的多重熔解过程。AFM显微镜的研究也观测到了二维DNA晶体受热解体后的图像，表明二维DNA晶体的熔解过程首先发生在DX分子瓦间的黏性末端，然后是DX分子瓦的解体，由此推测，在DNA晶体生长过程中单链DNA相互结合成分子瓦后，分子瓦进一步自组装成晶体。     

DNA microarray: a high throughput approach for methylation detection

We described a DNA microarray-based method combined with bisulphite treatment of DNA and regular PCR to examine hyper-methylation in promoter 1A of APC gene. A set of oligonucleotide probes were designed and immobilized on the aldehyde-coated glass slides for detecting the methylation pattern of 15 selected CpG sites in the region. The methylation status of 30 colorectal tumor samples have been examined by both of methylation-specific PCR (MS-PCR) and the present microarray method. The methylation pattern of the 15 CpG sites for the samples have been obtained with the microarray. A total of 19 samples out of 30 were methylated by microarray, in which five samples cannot be detected by MS-PCR due to the methylated CpG patterns not accordant to the MS-PCR primers. The detecting ratio for methylation of APC gene of colorectal tumor samples increased from 46.7% with MS-PCR to 63.3% with the microarray, which successfully demonstrated that DNA microarray-based method not only can obtained the methylation patterns for the related genes, but also decrease the false-negative results of methylation status by the conventional MS-PCR for the investigated genes.     

汞(Ⅱ)在螯合树脂聚[对乙烯苄基-(2-羟乙基)硫醚]上的吸附机理

研究了Hg2+在自合成的新型含硫螯合树脂-聚[对乙烯苄基-(2-羟乙基)硫醚](PSME)上的吸附机理.静态吸附结果表明吸附属于液膜扩散控制机理;树脂对Hg2+的等温吸附过程可以用Freundlich方程描述;在吸附过程中存在着明显的氧化还原现象.在较低浓度下,Hg2+主要被还原成Hg2+2和Hg0;而在较高浓度下Hg2+则主要被还原成Hg2+2.在两种情况下,-S-均被氧化成-SO2-键.     

Synthesis of an enzyme-like imprinted polymer with the substrate as the template, and its catalytic properties under aqueous conditions

Transition state analogues (TSAs) have long been regarded as ideal templates for the preparation of catalytically active synthetic imprinted polymers. In the current work, however, a new type of molecularly imprinted polymer (MIP) was synthesized with the substrate (homovanillic acid, HVA) as the template and hemin introduced as the catalytic center, with the use of plural functional monomers to prepare the active sites. The MIP successfully mimicked natural peroxidase, suggesting that it may not be imperative to employ a TSA as the template when preparing enzyme-like imprinted polymers and that the imprinted polymer matrix provided an advantageous microenvironment around the catalytic center (hemin), essentially similar to that supplied by apo-proteins in natural enzymes. Significantly, by taking advantage of the special structure of hemin and multiple-site interactions provided by several functional monomers, the intrinsic difficulties for MIPs in recognizing template molecules in polar solutions were overcome. The newly developed polymer showed considerable recognizing ability toward HVA, catalytic activity, substrate specificity and also stability, which are the merits lacked by the natural peroxidase. Meanwhile, the ease of recovery and reuse the MIP implies the potential for industrial application.     

4-(5-溴-2-噻唑偶氮)间苯二酚反相阳离子对HPLC测定痕量铌、钒、铑、铬

本文报道新试剂4-(5-溴-2-噻唑偶氮)间苯二酚(5-Br-TAR)为柱前衍生试剂,以阳离子表面活性剂作为对离子试剂,用含15 mmol／L的pH 5.8的乙酸-乙酸钠缓冲溶液、0.05 mmol／L溴化钠、10 mmol／L TBA·Br的乙腈-甲醇-水(42 : 13：45,V／V／V)三元体系为流动相,在C8柱上25min内HPLC测定了Nb(V)、V(V)、Rh(Ⅲ)和Cr(Ⅵ)的5-BR-TAR螯合物。当SNR=2时,检出限分别为Nb(V)1.0、V(V)1.6、Rh(Ⅲ)0.9和Cr(Ⅵ)1.9μg／L。该方法用于测定污水中的铬和钒,结果良好。     

无机-高分子磁性复合粒子的制备与表征

详细地研究了乳化剂用量对种子乳液聚合反应的影响,并成功地制备出粒径约300nm的苯乙烯/丙烯酸共聚小球。另外,还报道使用化学共沉淀法使无机粒子与高分子球复合,制备出高分子球为核,无机粒子为壳层的磁性复合粒子,使用XRD、TEM等手段对此复合粒子进行了表征。同时,进一步研究了这种复合粒子悬浮液的悬浮性能以及粘度随磁场的变化情况。