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应用薄层色谱法对工业品2 丙烯酰胺基 2 甲基丙烷磺酸(简称AMPS)进行了分析,以硅胶GF254作为吸附剂,从几种溶剂系统中优选了V(苯)∶V(甲醇)=2∶1溶液作为展开剂,用254nm紫外分析仪检测展开后的样品斑点。实验表明:AMPS的Rf为036,而其主要杂质丙烯酰胺(AM)的Rf为0.64;AMPS的最小检出限为5μg,展开时间约为25min。方法简便、快速、重现性好,有利于在生产过程中快速分析AMPS及其所含杂质,从而指导对AMPS的纯化处理。 相似文献
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以邻苯三酚(PA)为氧自由基释放剂,以四氮唑蓝(NBT)为显色剂,利用样品对PA自身氧化释放氧自由基的抑制作用,对样品清除自由基能力进行比色测定,效果满意。 相似文献
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在线单柱二维液相色谱法快速纯化牛胰腺中细胞色素C 总被引:1,自引:0,他引:1
用二维(弱阳,疏水)色谱柱首次完成了在线单柱二维液相色谱法快速纯化牛胰腺中的细胞色素C.在将牛胰腺粗提液进样到该二维色谱柱后,在弱阳离子交换模式下,以梯度洗脱方式进行一维色谱分离,并将分离得到的细胞色素C样品液收集到色谱仪的附加样品储液管内.然后将储液管中样品液全部排出,并二次进样到同一根二维色谱柱中,与此同时也完成了对该样品液的缓冲溶液交换,按疏水色谱(HIC)分离模式进行分离.最终对细胞色素C完成了第二维的HIC纯化.上述全部操作均为在线,在一具有正压的封闭体系中进行并可在52分钟内完成.细胞色素C的最终产品纯度高达94.7%(RSD=1.91%),质量回收率为80.5%(RSD=2.20%).预计此在线单柱二维液相色谱法也可能用于牛胰腺中其他功能蛋白的快速纯化,并可能将其放大到制备和生产规模. 相似文献
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OPA柱前衍生反相高效液相色谱法测定氨基酸含量 总被引:12,自引:0,他引:12
建立了邻苯二甲醛(OPA)手动柱前衍生反相高效液相色谱法测定样品中氨基酸含量的方法。以邻苯二甲醛(OPA)/3-巯基丙酸(3-MPA)为衍生试剂进行衍生,ODS柱分离,340nm检测,在40min内18种氨基酸全部得到基线分离。测定牛血清白蛋白(BSA)的氨基酸组成和小鼠血清中的游离氨基酸,取得满意的结果。 相似文献
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逆最小二乘法—导数谱同时测定锌,镉,汞和铅 总被引:1,自引:0,他引:1
本文研究了在碱性介质中,CPB存在下,meso-四(4-三甲铵基苯)卟啉与Zn(Ⅱ),Cd(Ⅱ),Hg(Ⅱ)和Pb(Ⅱ)络合物的导数光谱,提出了应用逆最小二乘法(或称CPA-矩阵法)原理对导数光谱进行解释,同时测定四组分的方法。应用本法对合成样品和水进行分析,结果满意。 相似文献
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用特性粘度([η])和羧值为参数,研究了双恶唑啉化合物(BOZ)对聚对苯二甲酸乙二酯(PET)的扩链反应动力学过程,表明BOZ是与PET中羧基反应,考察了不同工艺生产的PET的扩链效果,结果说明达到的[η]极大值取决于原始PET的[η]与羧值之比。 相似文献
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P.N. Joshi N.K. Ramaswamy M.K. Raval T.S. Desai P.M. Nair U.C. Biswal 《Journal of photochemistry and photobiology. B, Biology》1993,20(2-3):197-202
Wheat seedlings, grown for 7 days in the light, were allowed to senesce in the light or dark, and the change in the photosystem II (PS II) photochemistry of chloroplasts isolated from the primary leaves of these seedlings was investigated. The decrease in oxygen evolution and the fast fluorescence results indicated that the impairment of PS II in the leaves of seedlings senescing in the light was different from that in the leaves of seedlings senescing in the dark. Thermoluminescence studies showed a structural modification in the QB protein of chloroplasts isolated from leaves senescing in the light and an alteration in the S state transition of chloroplasts isolated from leaves senescing in the dark. 相似文献
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Magdalena Wyszyska Monika Nitsze-Wierzba Aleksandra Czelakowska Jacek Kasperski Joanna ywiec Magorzata Skucha-Nowak 《Molecules (Basel, Switzerland)》2022,27(13)
The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring the pathologies not only in the respiratory system but also in the oral cavity. It has shown a huge increase in its level in asthma and diseases of the oral cavity. It seems reasonable to undertake research on the impact of inflammation on the level of NO in exhaled air. The aim of the study is to make an evidence-based review of the application of NO levels in exhaled air in the diagnosis of inflammation and treatment monitoring on the basis of selected measuring devices. Methods and Results: This paper presents an example of the application of NO measurement in exhaled air in individual human systems. Selected measuring devices, their non-invasiveness, and their advantages are described. Discussion: The usefulness of this diagnostic method in pathologies of the oral cavity was noted. Conclusions: Measuring the level of NO in exhaled air seems to be a useful diagnostic method. 相似文献
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Methods of stripping voltammetry, quartz microgravimetry, and x-ray-fluorescence analysis are employed to explore the copper displacement process on thin electrodeposited layers of pure cobalt and nickel and on deposits of these metals with inclusions of copper. The displacement reaction proceeds at a considerable rate on cobalt in the sulfate and sulfosalicylate solutions and virtually does not proceed on nickel in both the sulfate or sulfate-chloride solutions. An estimate of the rate of the copper displacement reaction following a change in the concentration of copper ions in the solution and in the pH of the sulfosalicylate solution is given. A decrease in the contact exchange rate is facilitated by a decrease in the concentration of copper ions in solution and their participation in the formation of complexes. 相似文献
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The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised. 相似文献
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Changes in density and surface tension of water in silica pores 总被引:3,自引:0,他引:3
T. Takei K. Mukasa M. Kofuji M. Fuji T. Watanabe M. Chikazawa T. Kanazawa 《Colloid and polymer science》2000,278(5):475-480
The density and surface tension of water in small pores of silicas have been investigated. These physical properties of water
in the pores were calculated from a comparison of pore volumes and pore radii which were estimated from adsorption and desorption
isotherms of nitrogen and water. Below a pore radius of about 5 nm both the density and the surface tension of water in the
pores were smaller than those of the bulk liquid and decreased with a decrease in pore size. The density of water in the pores
decreased with an increase in the concentration of surface hydroxyl groups. Similarly the surface tension of water in the
pores is influenced by the surface hydroxyl groups. Anomalous changes in the density and surface tension of the water in the
pores are attributed to the interaction of water molecules with surface hydroxyl groups and hydrogen-bond formation among
water molecules.
Received: 20 April 1999 Accepted in revised form: 17 November 1999 相似文献
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Here we report on the role of oxygen in the evolution of radial heterogeneity in the fibre structure and properties of PAN fibres stabilized in air and vacuum at different temperatures. Modulus mapping by Nano-indentation showed heterogeneous modulus distribution in the fibres treated in air, while no variation in modulus was observed in fibres processed in vacuum. Raman spectroscopy and elemental analysis revealed that the temperature dependent oxygen diffusion from skin to core of the fibres assisted in the evolution of higher extent of sp2-hybridized carbons in the skin compared to core of the air treated samples. Conversely, no radial structure variations were observed in the vacuum treated fibres. Higher modulus in the skin of air-treated fibres was due to the formation of compact structures which was associated with the enhanced intermolecular interactions facilitated by the formation of C=C bonds within the polymer backbone, promoted by oxidative-dehydrogenation reaction. Supporting these observations, the fracture morphology examined by SEM showed a brittle fracture in the skin and ductile fracture in the core. 相似文献
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综述了壳聚糖、甲壳素在污水处理、电化学、原子吸收光谱、高效液相色谱、吸光光度法中的应用。引用文献28篇。 相似文献
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Internal repeats in protein sequences play a significant role in the evolution of protein structure and function. Applications of different bioinformatics tools help in the identification and characterization of these repeats. In the present study, we analyzed sequence repeats in a non-redundant set of proteins available in the Protein Data Bank (PDB). We used RADAR for detecting internal repeats in a protein, PDBeFOLD for assessing structural similarity, PDBsum for finding functional involvement and Pfam for domain assignment of the repeats in a protein. Through the analysis of sequence repeats, we found that identity of the sequence repeats falls in the range of 20–40% and, the superimposed structures of the most of the sequence repeats maintain similar overall folding. Analysis sequence repeats at the functional level reveals that most of the sequence repeats are involved in the function of the protein through functionally involved residues in the repeat regions. We also found that sequence repeats in single and two domain proteins often contained conserved sequence motifs for the function of the domain. 相似文献
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汽油铅与血铅的关系 总被引:2,自引:2,他引:2
秦俊法 《广东微量元素科学》1997,4(4):1-6
论述了汽油铅对人体血铅水平的影响,主要内容包括:血铅水平与大气铅水平的关系,大气铅水平与加铅汽油耗量的关系,汽油铅耗量与居民血铅水平的关系。 相似文献