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1.
周健  闫宏涛 《分析试验室》1994,13(4):19-20,26
以耐尔蓝为显色剂,采用分光光度法进行铵的测定。选择了NaOH碱解蒸馏分离氨的条件,探讨了表面活性剂OP,SDS增敏增溶作用,分别测定了雨水,土壤,绿叶中铵含量,结果满意。  相似文献   

2.
周光明  盛蓉生 《分析化学》1997,25(4):391-395
研究了在不同耐尔蓝A浓度,银溶胶,激发波长和pH值以及碘离子存在下,耐尔蓝A在银溶胶上的表面增强拉曼光谱特征。  相似文献   

3.
Nile red and Nile blue are highly fluorescent and photostable organic dyes from the benzo[a]phenoxazine family. They have been used as histological stains for imaging lysosomes and lipids in vitro. The dyes’ high quantum yields and solvent‐dependent optical properties make them ideal scaffolds for the development of pH probes and local polarity indicators. Reviews of the literature in this area are scarce with only one review ever published in 2006. It has been 10 years since and the field has evolved. This review aims to expand upon topics covered by the previous reviewers and to report on recent advances in the literature. As authors, we hope to convey a sense of scope and to spark renewed interest in this useful niche of dye chemistry.  相似文献   

4.
A monolayer of Nile Blue (NB) has been covalently immobilized on the self-assembled thiol-monolayer modified gold electrode. Cyclic voltammograms indicated a stable and reverse redox process of NB bonded on the electrode surface. The mechanisms of redox process coupling with proton transfer were proposed. The NB-modified electrode showed excellent electrocatalytic activity toward Nicotinamide adenine dinucleotide (NADH) oxidation and horseradish peroxidase (HRP) reduction. A hydrogen peroxide biosensor based on NB as a mediator has been demonstrated.  相似文献   

5.
The single envelope glycoprotein of vesicular stomatitis virus was used as a specific probe of glycosyltransferase activities in fibroblasts from two cystic fibrosis patients, an obligate heterozygous carrier and a normal individual. Gel filtration of pronase-digested glycopeptides from both purified virions and infected cell-associated VSV glycoprotein which had been labeled with[3H] glucosamine did not reveal any significant differences in the glycosylation patterns between the different cell cultures. All 4 cell lines were apparently able to synthesize the mannose- and glucosamine- containing core structure and branch chains terminating in sialic acid which are characteristic of asparagine-linked carbohydrate side chains in cellular glycoproteins. Analysis of tryptic glycopeptides by anion-exchange chromotography indicated that the same 2 major sites on the virus polypeptide were recognized and glycosylated in all 4 VSV-infected cell cultures. These studies suggest that the basic biochemical defect(s) in cystic fibrosis is not an absence or deficiency in enzymes responsible for the biosynthesis of complex carbohydrate side chains.  相似文献   

6.
耐尔兰A修饰碳纤维微柱电极的电化学性质研究   总被引:2,自引:0,他引:2  
用循环伏安法将碳纤维柱电极表面官能团化,利用正负离子间的静电作用将耐尔兰A修饰在碳纤维微柱电极(CFMCE)表面,对该修饰电极的电化学性质进行研究,讨论了它的稳定性,测定了不同PH值下固定化耐尔兰A电极反应的表现电子转移速率常数k、电荷转移系数α以及参加电极反应的H^+数,实验表明:电极对血戏蛋白在CFMCE上的还原有电催化作用。  相似文献   

7.
IntroductionItisgenerallyacceptedtodaythattherearethreekindsofbindingmodelsforsmallmoleculestoDNA ,whichrefertointercalativebinding ,groovebindingandelectrostaticbinding .Inthesebindingmodels ,theinter calativebindingisthoughtastobethestrongestbindingbec…  相似文献   

8.
耐尔蓝-钍钼杂多酸光度法测定钍   总被引:4,自引:0,他引:4  
本文研究超高灵敏光度法测定钍。在聚乙烯醇(PVA)存在下,耐尔蓝(NB)与钍钼杂多酸络阴离子形成离子缔合物。在1.2mol/L高氯酸介质中缔合物的最大吸收位于590nm,摩尔吸光系数ε值4.45×106L·mol-1·cm-1,钍量在0~28μg/L范围服从比耳定律;测定极限C(Th)3.4μg/L(n=9);对20μg/LTh分析9次的相对标准偏差1.5%;缔合物的摩尔组成Th:Mo:NB=1:12:3。考察了50多种共存离子影响,允许100倍量Ce(Ⅲ)、50倍量U(Ⅵ)和等量Ti(Ⅳ)存在。本法用于地质样品中钍的测定,结果满意。  相似文献   

9.
The responses of normal human skin fibroblasts exposed to simulated sunlight produced by a solar simulator were examined. The parameters investigated were cellular survival, excision repair and the inhibition and recovery of DNA synthesis. The latter two effects were examined using the bromodeoxyuridine photolysis assay and the alkaline step elution assay respectively. The results of these experiments are consistent with the conclusion that the lesions induced by simulated sunlight represent a mixture of damage which elicits cellular responses and repair mechanisms similar to those manifested by cells irradiated with UVC and UVA radiation.  相似文献   

10.
11.
A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodium-p-styrenesulfonate) (PSS) acts as the mediator between the immobilized HRP and the electrode surface. The response of the biosensor to hydrogen peroxide has been investigated. The linear range of the biosensor to hydrogen peroxide was from 0.20 mmol/L to 7.03 mmol/L with a sensitivity of 8.45 μA/(mmol/L).  相似文献   

12.
锆钼杂多酸-耐尔蓝离子缔合显色反应的研究   总被引:2,自引:0,他引:2  
在聚乙烯醇(PVA)存在下,耐尔蓝(NB)与锆钼杂多酸(ZrMo)形成离子缔合物,其λ_(max)位于615nm,表观摩尔吸光系数e值为3.71×10~5L·mol~(-1)·cm~(-1),线性范围0~5μgzr/25ml。络合物至少稳定24h。考察了30多种共存离子的影响,允许25倍量铪存在。测定锆的适宜条件为[HClO_4]=0.9mol/L,[MoO_4~(2-)]=7.5×10~(-5)mol/L,[NB]=5.5×10~(-5)mol/L,PVA 0.08%。方法已用于岩矿中锆的测定,结果满意。用摩尔比法和平衡移动法测定缔合物的摩尔比为ZrMo:NB=1:4。探讨了反应机理。  相似文献   

13.
用耐尔蓝和高碘酸盐催化光度法测定痕量铱(Ⅳ)   总被引:11,自引:1,他引:10  
研究了在弱酸性介质中,利用铱(Ⅳ)催化高碘酸钾氧化耐尔蓝(NB)形成桃红色产物,建立了催化光度法测定痕量铱的新方法。方法的线性范围为4.0 ̄40μg/L;检出限为4.0μg/L,对40μg/L Ir(Ⅳ)测定的RSD为2.02%。本法满意地用于某些矿石和冶金产品中铱的测定。  相似文献   

14.
探针体耐尔蓝(NB)与DNA结合反应研究   总被引:1,自引:0,他引:1  
应用微相吸附-光谱修正(MPASC)新技术研究DNA与耐尔蓝(NB)探针分子间的相互作用,分析生物大分子内静电场的形成与Langmuir吸附的关联性,测定了结合产物结合比、平衡常数等.通过在pH=10.38介质中对DNA-NB反应的光谱分析,结果表明产物结合比NB∶ DNA-P=3∶ 1、平衡常数K=3.33×105,摩尔吸收系数ε660 nm=4.81×103 L/mol cm.样品分析表明DNA回收率95.6%~108%,相对标准偏差RSD=2.8%.  相似文献   

15.
This paper reports a poly-Nile Blue (PNB) sensing film based electrochemical sensor and the application in food analysis as a possible alternative for electrochemical detection of nitrite. The PNB-modified electrode in the sensor was prepared by in situ electropolymerization of Nile Blue at a prepolarized glassy carbon (GC) electrode and then characterized by cyclic voltammetry (CV) and pulse voltammetry in phosphate buffer (pH 7.1). Several key operational parameters affecting the electrochemical response of PNB sensing film were examined and optimized, such as polarization time, PNB film thickness and electrolyte pH values. As the electroactive PNB sensing film provides plenty of active sites for anodic oxidation of nitrite, the nitrite sensor exhibited high performance including high sensitivity, low detection limit, simple operation and good stability at the optimized conditions. The nitrite sensor revealed good linear behavior in the concentration range from 5.0 × 10−7 mol L−1 to 1.0 × 10−4 mol L−1 for the quantitative analysis of nitrite anion with a limit of detection of 1.0 × 10−7 mol L−1. Finally, the application in food analysis using sausage as testing samples was investigated and the results were consistent with those obtained by standard spectrophotometric method.  相似文献   

16.
We report the observation of ground state prototropic equilibrium of the dye Nile Blue in Triton-X 100/benzene-hexane reverse micellar system. In the absence of water, the deprotonated form of the dye is predominant. Addition of water produces the protonated form. At highest water loading, the equilibrium is still shifted towards the deprotonated form as revealed by the absorption spectrum. In neat Triton-X 100 also, the dye is present almost predominantly in the deprotonated form as revealed by the absorption spectrum. The average fluorescence lifetime of the dye is greater in neat Triton-X 100 than in Triton-X 100 reverse micelles, when no water is added. Addition of water to the reverse micelles increases the average lifetime of the deprotonated species. We offer possible explanations to the above observations by discussing the structure and properties of the Triton-X 100/benzene-hexane reverse micelles.  相似文献   

17.
—Action spectra for UV-induced lethality as measured by colony forming ability were determined both for a normal human skin fibroblast strain (lBR) and for an excision deficient xeroderma pigmentosum strain (XP4LO) assigned to complementation group A using 7 monochromatic wavelengths in the range 254-365 nm. The relative sensitivity of the XP strain compared to the normal skin fibroblasts shows a marked decrease at wavelengths longer than 313 nm. changing from a ratio of about 20 at the shorter wavelengths to just greater than 1.0 at the longer wavelengths. The action spectra thus indicate that the influence on cell inactivation of the DNA repair defect associated with XP cells is decreased and almost reaches zero at longer UV wavelengths. This would occur, for example, if the importance of pyrimidine dimers as the lethal lesion decreased with increasing wavelength. In common with other studies both in bacterial and mammalian cells, our results are consistent with pyrimidine dimers induced in DNA being the major lethal lesion in both cell strains over the wavelength range 254-313 nm. However, it is indicated that different mechanisms of inactivation operate at wavelengths longer than 313 nm.  相似文献   

18.
The culture of cells in a microbioreactor can be highly beneficial for cell biology studies and tissue engineering applications. The present work provides new insights into the relationship between cell growth, cell morphology, perfusion rate, and design parameters in microchannel bioreactors. We demonstrate the long-term culture of mammalian (human foreskin fibroblasts, HFF) cells in a microbioreactor under constant perfusion in a straightforward simple manner. A perfusion system was used to culture human cells for more than two weeks in a plain microchannel (130 microm x 1 mm x 2 cm). At static conditions and at high flow rates (>0.3 ml h(-1)), the cells did not grow in the microchannel for more than a few days. For low flow rates (<0.2 ml h(-1)), the cells grew well and a confluent layer was obtained. We show that the culture of cells in microchannels under perfusion, even at low rates, affects cell growth kinetics as well as cell morphology. The oxygen level in the microchannel was evaluated using a mass transport model and the maximum cell density measured in the microchannel at steady state. The maximum shear stress, which corresponds to the maximum flow rate used for long term culture, was 20 mPa, which is significantly lower than the shear stress cells may endure under physiological conditions. The effect of channel size and cell type on long term cell culture were also examined and were found to be significant. The presented results demonstrate the importance of understanding the relationship between design parameters and cell behavior in microscale culture system, which vary from physiological and traditional culture conditions.  相似文献   

19.
用金钨杂多酸和耐尔蓝光度法测定纳克量金   总被引:3,自引:2,他引:3  
在阿拉伯胶存在下,金与钨酸钠和耐尔蓝(NB)形成离子缔合物,它的最大吸收位于580nm,表观摩尔吸光系数ε值为2.38×10^7L·mol^-1·cm^-1,体系至少稳定24h。金量在0 ̄4.4μg/L范围内服从比尔定律,检测限(3σ)为0.069μg/L(n=12),对4.0μg/L Au(Ⅲ)测定的相对标准偏差为1.9%(n=11),离子缔合物的摩尔比为Au(Ⅲ):NB=1:3。考察了40多种  相似文献   

20.
Abstract— We present experimental evidence that demonstrates directly how the subcellular localization and redistribution of two nile blue derivatives, 5-ethylamino-9-diethyl-ami-nobenzo[ α ]phenothiazinium chloride (EtNBS) and 5-ethylamino-9-diethyl-aminobenzo[ α ]phenoselenazinium chloride (EtNBSe), affect oxygen consumption during irradiation of sensitized multicell EMT6 spheroids. Specifically, two well-defined phases of oxygen consumption are observed during treatment, with the onset of the second phase being a fluence-dependent event. Fluorescence microscopy during irradiation of EtNBS-sensitized EMT6 monolayer cultures indicates that sensitizer redistribution from intracellular organelles, presumably lysosomes, to the cytosol can explain the onset of the second oxygen consumption phase. This event requires eight times fewer photons for EtNBSe than for EtNBS, consistent with the higher singlet oxygen yield of the former dye. The existence of a second oxygen consumption phase suggests that the aggregated form of the dye is a less efficient photodynamic agent. Moreover, we present evidence suggesting that damage to the primary sites of localization might be less significant than damage incurred by the sites to which the sensitizer redistributes during irradiation.  相似文献   

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