基于可见吸收信号的乳酸脱氢酶光纤传感器

报道一种测定乳酸脱氢酶活力的基于可见吸收信号的光纤生物传感器，在该传感体系中，通过辅酶Ｉ的氧化还原对（ＮＡＤ＾＋／ＮＡＤＨ）将乳酸脱氢酶和心肌黄酶催化的两个脱氢过阳以耦合，第一个脱氢过程对分析对象进行了化学识别，第二个脱氢过程引起可见吸收信号的变化，该传感器对０～４００Ｕ／Ｌ的乳酸脱氢酶有线性响应关系，检测下限为４８ＵＬ，该传感器已用于人体血清中乳酸脱氢酶活力的测定。     

酶法测定乳酸

利用乳酸在氧化型烟酰胺腺嘌呤二核苷酸（NAD）存在的条件下,由乳酸脱氢酶（L-LDH）催化生成丙酮酸和还原型烟酰胺腺嘌呤二核苷酸（NADH）。通过测定NADH吸光度的变化率可得出乳酸的酶促反应速度,并制得标准曲线。样品中的乳酸可由标准曲线求得。讨论了试剂用量、pH、温度和共存离子对测定的影响。     

电分析化学研究锌在乳酸脱氨酶和谷氨酸脱氢酶体系中的作用

酶是生物催化剂，在数以千计的酶中，第一大类以烟酰胺腺嘌呤核苷酸（ＮＡＤ／ＮＡＤＨ）为辅酶的多种氧化－还原酶需要金属离子作为辅助因子而发生独特的催化功能。其中含锌的醇脱氨酶（ＡＤＨ）是目前研究得最多的一种。本文用电化学分析法研究稀土离子对乳酸脱氢酶（ＬＤＨ）和谷氨酸脱氢酶（ＧＤＨ）两体系的作用时也探讨了Ｚｎ２＋在此两体系中的作用。结果指出在ＬＤＨ体系中不需要 Ｚｎ２＋；在 ＧＤＨ（牛肝中提取）体系中， Ｚｎ２＋是一种强抑制剂，Ｅｕ３＋可以缓解它的抑制作用，但是在黄瓜根系提取的粗ＧＤＨ体系中，Ｚｎ２＋必需存在于反介质中起激活酶的催化作用。     

介体型乳酸脱氢酶生物传感器的研制及应用

本报道了能对丙酮酸产生良好响应的电流型乳酸脱氢酶生物传感器。该传感器以耐尔兰Ａ修饰浸石墨电极为基体电极，将酶直接固化在蚕丝蛋白膜上。在ＰＨ７．４的ＮａＨ２ＰＯ４－ＮａＯＨ介质中，当２．４×１０＾－４ｍｏｌ／Ｌ的辅酶Ｉ（ＮＡＤＨ）存在下，该传感器的响应电流与丙酮酸浓度在３．２×１０＾－５ｍｏｌ／Ｌ范围内有良好的线性关系。响应时间为６０ｓ．本讨论了影响传感器响应的各种因素，用此传感器测定了人血清中     

用吐温80—盐—水液—固萃取体系从兔肌中分离纯化乳酸脱氢酶

用吐温８０－盐－水液－固萃取体系从兔肌中分离纯化乳酸脱氢酶＊柳畅先邓江天雷锦桂游文淑李步海（中南民族学院化学系武汉４３００７４）关键词液－固萃取吐温８０乳酸脱氢酶中图分类号Ｏ６５８．２非有机溶剂液－固萃取体系是一种新的萃取体系，其特点之一是聚合物固相...     

乙醛酸缩氨基硫脲和锌（Ⅱ）、铅（Ⅱ）、铜（Ⅱ）、锰（Ⅱ）、镍（Ⅱ）、钴（Ⅱ）配合物的薄层色谱与紫外光谱的研究

用正相薄层色谱法研究了乙醛酸缩氨基硫脲和锌（Ⅱ）、铅（Ⅱ）、铜（Ⅱ）、锰（Ⅱ）、镍（Ⅱ）、钴（Ⅱ）配合物的色谱行为，各组分配合物的比移植Ｒｆ相差较大，得到了满意的分离。讨论了该系列配合物正相吸附薄层色谱比移植与紫外光谱Ｒ带λ（ｍａｘ）变化关系的一致性。     

乙醛酸缩氨基硫脲和锌（Ⅱ）、铅（Ⅱ）、铜（Ⅱ）、锰（Ⅱ）、镍（Ⅱ）、钴（Ⅱ）配合物的薄层色谱与紫外光谱的研究

 用正相薄层色谱法研究了乙醛酸缩氨基硫脲和锌（Ⅱ）、铅（Ⅱ）、铜（Ⅱ）、锰（Ⅱ）、镍（Ⅱ）、钴（Ⅱ）配合物的色谱行为，各组分配合物的比移植Ｒｆ相差较大，得到了满意的分离。讨论了该系列配合物正相吸附薄层色谱比移植与紫外光谱Ｒ带λ（ｍａｘ）变化关系的一致性。     

乳酸脱氢酶的流动注射分析—电化学检测体系的研究

本文研究了L－乳酸盐＋NADLDH／→/←丙酮酸＋NADH＋H^ 的酶反应动力曲线及NADH的电化学性质与流动伏安检测法，建立了乳酸脱氢酶（LDH）的单泵单液路流动注射分析－电化学检测体系，可测定LDH的活性和浓度。     

乳酸脱氢酶—水体系中不冻结水量的测定

许多研究表明,在蛋白质-水体系中由于蛋白质分子和水分子间的相互作用,使蛋白质周围的水的性质和状态发生了变化,其中一部份水分子以氢键与蛋白质分子表面的极性基因相结合,成为不冻结水(在我们的实验条件下,冷却至-40℃仍不冻结的水),而另一部份     

四氢呋喃聚合向丁二酸酐链转移的研究

四氢呋喃聚合向丁二酸酐链转移的研究栗方星，马克勤，陈琰，文佳，霍玉杰（南开大学化学系，天津，３０００７１）（天津安普公司，天津）关键词ＴＨＦ，ＴＤＩ，ＣＨ_３ＣＯＳｂＣｌ_６，表观聚合速率常数在ＴＨＦ阳离子聚合的过程中，活性中心向丁二酸酐链转移［１］可...     

层状复合氢氧化物对乙酰苯甲酸的负载与体外释放

共沉淀-微波晶化法合成层状复合氢氧化物(LDH)后, 用不同方式将乙酰苯甲酸(ASP)组装到LDH层间制成载药体LDH-ASP, 通过对合成及药物释放前后的液相分析与固相表征数据研究了LDH对ASP的负载及载药体LDH-ASP在磷酸盐介质的溶释现象. 结果表明: LDH层间通道是负载、贮存及控制药物释放的微观基础; 载体选择、药物配比、反应能量供给方式及搅拌强度是决定并影响LDH-ASP载药效率的基本因素, LDH-ASP结构参数可以反映药物负载情况、并与其释放性能明确相关; LDH对ASP的负载与释放均致晶胞参数改变、结晶度下降; 载药体与前体的晶态属性、热力学行为及表面特性相似, 而释放药物后固相的晶态性征减弱、无定形性增强、通道吸附活性降低, 有利于使命后载体在体内降解消除.     

层状双金属氢氧化物及其复合材料加速电解水制氢的研究进展

随着经济社会的不断发展和能源的不断消耗,开发清洁能源已引起研究者们的广泛关注。层状双金属氢氧化物(LDH)具有典型的层状结构、制备难度低、组成易调节等优点,在电催化分解水方面表现出可与贵金属催化剂相媲美的性能。目前LDH催化剂仍然存在稳定性不足、活性位点辨别不明、电催化反应机理模糊不清等科学问题亟待解决。本文首先介绍了LDH材料的性质和制备方法,重点从元素和化合物对LDH材料结构和性能的调控、取代阳极OER以及海水氧化三个方面综述了LDH材料在电催化制氢方面的研究进展,阐述了LDH复合材料的形貌、界面作用及化合物之间的协同作用。最后对LDH材料更深层次的研究方向作出展望。     

The mechanism on the pH value influencing the property of glutamic acid/layered double hydroxide compounds

The influence of zeta potential, altered by the pH value in synthesis, on the property of glutamic acid (Glu for short)/LDH compounds has been studied. It was found that the layer charges increased first then decreased as the pH value increased, and the layer charge had prominent effect on the properties of the samples. The crystallinity degree and the interlayer spacing increased gradually and the morphology changed from tubular or fibrous to platelet structure as the layer charge increased. And a model has been proposed to explain how pH values in the synthesis influence the LDH compound property by altering their layer charges.     

From Zn-Al layered double hydroxide to ZnO nanostructure:Gradually etching by sodium hydroxide

Zn-Al layered double hydroxide(LDH) was used as precursor to produce ZnO nanostructures through dissolution of aluminum hydroxide in caustic soda.The Zn-Al LDH could transform into different nanostructures of ZnO on LDH nanosheets and even pure ZnO nanorods under various NaOH concentration.The formed ZnO nanorods vertically aligned on both LDH sides.UV-vis diverse reflectance spectra show that the obtained ZnO nanorods have a band gap of approximately 3.05 eV.Such ZnO/LDH nanostructures might be used as photocatalyst in the organic pollutant decomposition.     

二价金属离子影响乳酸脱氢酶活性的单扫伏安研究

探讨了５种二价金属离子对乳酸脱氢酶在辅酶ＮＡＤＨ存在下转化丙酮酸为乳酸催化体系的影响、结果表明，Ｚｎ＾２＋，Ｃａ＾２＋与ＬＤＨ活性无影响，Ｍｎ＾２＋有抑制作用，而Ｃｕ＾２＋，Ｍｇ＾２＋在低浓度时有微弱的促进作用。     

软模板法制备三维花状MgAl-LDH及其吸附性能

采用软模板法,以十二烷基硫酸钠(SDS)为模板剂,经水热合成制得三维花状双金属(Mg Al)氢氧化物(3D-Mg Al LDH)。通过XRD、FT-IR、SEM及TEM等表征手段,研究了原料Mg/Al物质的量之比、SDS浓度及反应时间对产物微观结构和表面形貌的影响规律,并初步探讨了3D-Mg Al LDH的形成机理。结果表明,当n_(Mg)/n_(Al)=2,SDS浓度为0.1 mol·L~(-1),水热反应时间为6 h时,可形成结晶度良好、花球形貌完整,纳米片厚度均一的三维花状LDH。在3D-Mg Al LDH的形成过程中,SDS既以阴离子形态参与LDH形成,又因其类球状胶束特性附着在已形成的LDH表面或边缘诱导LDH纳米片交叉生长形成三维花状。吸附实验表明,3D-Mg Al LDH对非离子型有机污染物具有良好的吸附作用,最大吸附量约为31 mg·g~(-1),去除率达到100%。     

Structure,thermal stability,and photocrosslinking characterization of HDPE/LDH nanocomposites synthesized by melt‐intercalation

Structure, thermal properties, and influence of layered double hydroxide (LDH) fillers on photocrosslinking behavior of high‐density polyethylene (HDPE)/LDH nanocomposites have been studied in the present article. The X‐ray diffraction and transmission electron microscopy analysis demonstrate that the completely exfoliated HDPE/LDH nanocomposites can be obtained by controlling the organomodified LDH loading via melt‐intercalation. The data from the thermogravimetric analysis show that the HDPE/LDH nanocomposites have much higher thermal stability than HDPE sample. When the 50% weight loss was selected as a comparison point, the decomposition temperature of HDPE/LDH sample with 5 wt % LDH loading is ～40 °C higher than that of HDPE sample. The effects of UV‐irradiation on the HDPE/LDH nanocomposites show that the photoinitiated crosslinking can destroy the completely exfoliated structure to form the partially exfoliated structure, which decreased the thermal stability of the nanocomposites. However, the thermal stability of photocrosslinked samples can increase with increasing the UV‐irradiation time. The effect of LDH loading on the gel content of UV‐irradiated nanocomposites shows that the LDH materials can greatly absorb the UV irradiation and thus decrease the crosslinking efficiency. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3165–3172, 2006     

Exfoliation of layered double hydroxides by use of zwitterionic surfactants in aqueous solution

A new strategy to exfoliate inorganic layered double hydroxide (LDH) solids to micrometer-sized and positively-charged nanosheets in aqueous solution is presented. The procedure involves intercalation of zwitterionic surfactant into the decarbonated LDH by ion exchange, followed by simply stirring the surfactant-intercalated LDH in an aqueous solution of pH?=?2. Since the charge of zwitterionic surfactant can be varied from anionic to cationic by adjusting the pH, the zwitterionic ions present in the interlayer were converted to cationic at pH?=?2, resulting in the exfoliation of LDH by electrostatic repulsion. The delaminated LDHs nanosheets were confirmed by XRD, TEM, and AFM analyses. This simple method did not need reflux at high temperature, overcame the drawback of using organic solvents, and even resulted in a stably colloidal dispersion of nanosheets.     

层状复合金属氢氧化物-聚丙烯酸钠水分散体系的双絮凝现象及机理探讨

研究了聚丙烯酸钠(PAAS)对镁铝型层状复合金属氢氧化物(MgAl-LDH)的胶体水分散体系稳定性的影响. 利用总有机碳(TOC)分析技术测定了PAAS在LDH颗粒上的吸附量, 并利用ζ电位表征了LDH颗粒的电性质. 实验结果表明, 在质量分数为1%的LDH水分散体系中加入0.006~2.400 mmol/L PAAS, 随着PAAS浓度的增加, LDH-PAAS混合体系出现了絮凝-分散-再絮凝变化. 同时, 随着PAAS浓度的增加, PAAS在LDH颗粒上的吸附导致颗粒ζ电位由正减至0, 并进一步负向增加, 颗粒间静电斥力先减小后增加, 因此体系先絮凝再分散. 随着LDH颗粒负电性的进一步增强, 未吸附的PAAS引发颗粒间产生的空缺引力成为体系再次絮凝的主要原因. 对吸附PAAS的LDH颗粒的红外光谱分析表明, PAAS主要通过-COO-与LDH的相互作用而吸附在颗粒上.     

catalytic activity of comgal, coal and mgal of mixed oxides derived from hydrotalcites in the selective catalytic reduction of no with ammonia

Summary Calcined CoMgAl LDHs and a Co-impregnated LDH were characterized by XRD, N₂ physisorption, TPR and ICP elemental analysis, then tested in the selective catalytic reduction (SCR) of NO with ammonia. Cobalt deposited by impregnation on LDH leads to the more active and selective catalyst. On this type of catalyst nearly 80% of conversion and selectivity to N₂ were reached at 578 K with a volume space velocity of 2200 h^-1.