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1.
葡萄糖氧化酶共价交联于蛋膜上的葡萄糖传感器   总被引:3,自引:0,他引:3  
邓健  袁亚莉 《分析化学》1998,26(10):1257-1259
以牛血清白蛋白-戊二醛为交联剂,将葡萄糖氧化酶固定地鸡蛋膜上,氧电极作电化学敏感元件,制成葡萄糖氧化酶电极。传感器的响应范围为4.0×10^-6-2.4×10^-3mol/L;检测限为1.210^-6mol/L。该传感器具有线性范围宽,灵敏度高,使用寿命长等优点。  相似文献   

2.
为了解吉林省矿泉水的放射性水平及分布特点,依据《饮用天然矿泉水标准》,采用FD- 125型室内氡钍测定仪及FH 463A型自动定标器和BH 1217型弱α,β测量仪对5个行政区域矿泉水中226 Ra和总α、总β放射性核素水平进行了测定.结果表明,矿泉水中226Ra、总α、总β的放射性活度范围为5.5~11.4 mBq/L,1.0~109.3 mBq/L,24.9 ~531 mBq/L.110个矿泉水样品中226Ra和总α总β放射性活度均低于国家标准限值  相似文献   

3.
本文研究了用电位滴定法测定模拟高放废液中游离酸的方法。用草酸钾做络合剂以消除Fe^3+、Al^3+、Nd^3+等多种水解离子的影响,用标准碱直接进行电位滴定,即可快速准确地测定模拟高放废液中游离酸的含量。方法的相对标准偏差为1.8%,标准加入回收率为100-101%,能为放射性废物固化试验提供可靠的分析数据。  相似文献   

4.
为了解吉林省矿泉水的放射性水平及分布特点,依据《饮用天然矿泉水标准》,采用FD- 125型室内氡钍测定仪及FH 463A型自动定标器和BH 1217型弱α,β测量仪对5个行政区域矿泉水中226 Ra和总α、总β放射性核素水平进行了测定.结果表明,矿泉水中226Ra、总α、总β的放射性活度范围为5.5~11.4 mBq/...  相似文献   

5.
以Brodio线性化简单图解法对前驱体草酸氧钛钡热分解过程中三段动力学参数进行了计算,结果表明,三段热分解的反应级数分别为2、2和0,活化能为96.8,165.1和172.2kj/mol,频率因子为1.03×10^11,5.64×10^8和2.63×10^6s^-1,由热分解动力学参数优化热处理工艺制得高纯超细BaTiO3粉体。  相似文献   

6.
螯合纤维的研究:Ⅱ.含偕胺肟基螯合纤维的吸附性能   总被引:9,自引:1,他引:9  
本文系统地研究了通过枝共聚和偕胺肟化反应制备的以聚乙烯醇缩甲醛(PVF)无纺布为基体的含偕胺肟基螯合纤维对碱土,过渡贵重,稀土和放射性金属离子的螯合吸附行为,测定了在不同温度下的吸附速率曲线。并且首次发现这种螯合基团有氧化-还原性性质,能将高价金属离子如Au^3^+还原成价态,即还原成元素金。  相似文献   

7.
^99mTc-ECD是目前脑显像剂中一种较为理想的放射性诊断药物。本文介绍了从基本原料(L)半胱氨酸开始合成配体ECD(N,N”-乙撑-双-L-半胱氨酸乙酯),采用锡作还原剂实现了一步法^99mTc标记ECD,并对制备的^99mTc-ECD进行了初步动物实验以评价其生物学性能。  相似文献   

8.
苯乙烯—甲基丙烯酸甲酯嵌段共聚物的合成与表征   总被引:1,自引:0,他引:1  
采用阴离子聚合技术合成了一系列苯乙烯-甲基丙烯酸甲酯的两嵌段共聚物。采用GPC、FTIR、NMR(^1H NMR,^13C NMR和固体NMR)和DMA等手段进行了表征。结果表明,所得产物为高分子量,窄分布,具有微相分离结构的两嵌段共聚物。  相似文献   

9.
研究了不同浓碱皂化的D2EHPA-正庚烷体系萃取-系列稀土离子(La^3+-Lu^3+)放射性的Pm除外)过程中有机相的FTIR光谱变化规律,结果说明,D2EHPA萃取稀土离子后,P-O基团5的红外吸收频率降低,吸收强度升高,说明P-O基团与稀土离子发生配位;红外光谱研究研究结果表明:不同稀土离子与P-O配位能力有差别,从La^3+-Sm^3+sgn wug celtwye uqw fulje s  相似文献   

10.
反向流动注射化学发光法测定痕量铁   总被引:10,自引:1,他引:10  
周延秀  孙杰 《分析化学》1997,25(3):334-337
基于邻菲别名林对高碘酸钾-碱性鲁米诺-铁体系发光强度的增敏作用建立了水体中总铁的反向流动性化学发光检测方法。该法线性范围在1×10^-4-10mg/L,检测限为3×10^-6mg/L,对于5×10^-3mg/L Fe测定9次的相对标准偏差为0.9%。此方法已用在水处理中总铁的监测。  相似文献   

11.
国内光催化研究进展简述   总被引:4,自引:0,他引:4  
郑云  潘志明  王心晨 《催化学报》2013,34(3):524-535
分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO2还原、环境净化和选择性有机合成等方面.  相似文献   

12.
青蒿素研究进展   总被引:20,自引:0,他引:20  
青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。  相似文献   

13.
Reactions in droplets in microfluidic channels   总被引:5,自引:0,他引:5  
Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.  相似文献   

14.
The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (Asi). In order to document the methylation process in humans, the kinetics of Asi, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of Asi. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As2O3) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of Asi metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of Asi uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.  相似文献   

15.
Gemini表面活性剂合成进展   总被引:46,自引:0,他引:46  
系统总结了近百种Gemini表面活性剂的合成路线和方法,并且按照其结构特点分门别类地进行比较和归纳,对今后Gemini表面活性剂的合成发展方向提出了一些看法,这对促进此类新颖表面活性剂的工业化进程将具有指导意义。  相似文献   

16.
Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.  相似文献   

17.
李菊仁  何兴涛 《合成化学》1993,1(4):296-303
报导了近几十年来国内外关于乙基香兰素的研究进展与动态,并简单介绍了本文作者在该方面所取得的研究成果,参考文献33篇。  相似文献   

18.
Summary At the session of the WPAC of Fechem on education in analytical chemistry it was concluded that it is now essential to include chemometrics and basic knowledge of computers in all courses on analytical chemistry.
Tendenzen in der analytisch-chemischen Ausbildung
Zusammenfassung Bei einer Tagung der WPAC über die Lehre auf dem Gebiet der analytischen Chemie wurde bei der Betrachtung neuer Aspekte festgestellt, daß vor allem Chemometrie und Grundkenntnisse in Computertechnik in die Ausbildung aufgenommen werden sollten.
  相似文献   

19.
钙是宏量元素,是人体中含量较高的元素之一,体内99%的钙构成骨骼和牙齿以及维持骨骼结构,1%的钙调节人体重要生理功能。钙的含量过高或过低都与许多疾病有关,只有保持一种平衡状态,才能使机体处于正常环境。  相似文献   

20.
Summary: The recently developed initiation system, activators generated by electron transfer (AGET), is used in atom transfer radical polymerization (ATRP) in the presence of a limited amount of air. Ascorbic acid and tin(II ) 2‐ethylhexanoate are used as reducing agents in miniemulsion and bulk, respectively. An excess of reducing agent consumes the oxygen present in the system and, therefore, provides a deoxygenated environment for ATRP. ATRP of butyl acrylate is successfully carried out in miniemulsion and in the presence of air. During polymerization the radical concentration remains constant. The polymerization reaches over 60% monomer conversion after 6 h, which results in polymers with a predetermined molecular weight = 14 000 g · mol−1 and a low polydispersity ( = 1.23). AGET ATRP of styrene is also successful in bulk in the presence of air, as evidenced by linear semi‐logarithmic kinetics, which leads to polystyrene with an of 13 400 g · mol−1 and a low polydispersity index ( = 1.14).

Appearance of miniemulsion before and after the reducing agent ascorbic acid was added (left); and GPC traces representing molecular weights during the AGET ATRP of BA in miniemulsion in the presence of air (right).  相似文献   


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