Study on the secondary structure and hydration effect of human serum albumin under acidic pH and ethanol perturbation with IR/NIR spectroscopy

Human serum albumin(HSA)is the most abundant protein in plasma and plays an essential physiological role in the human body.Ethanol precipitation is the most widely used way to obtain HSA,and pH and ethanol are crucial factors affecting the process.In this study,infrared(IR)spectroscopy and near-infrared(NIR)spectroscopy in combination with chemometrics were used to investigate the changes in the secondary structure and hydration of HSA at acidic pH(5.6-3.2)and isoelectric pH when ethanol concentration was varied from 0%to 40%as a perturbation.IR spectroscopy combined with the two-dimensional correlation spectroscopy(2DCOS)analysis for acid pH system proved that the secondary structure of HSA changed significantly when pH was around 4.5.What's more,the IR spectroscopy and 2DCOS analysis showed different secondary structure forms under different ethanol concentrations at the isoelectric pH.For the hydration effect analysis,NIR spectroscopy combined with the McCabe-Fisher method and aquaphotomics showed that the free hydrogen-bonded water fluctuates dynamically,with ethanol at 0-20%enhancing the hydrogen-bonded water clusters,while weak hydrogen-bonded water clusters were formed when the ethanol concentration increased continuously from 20%to 30%.These measurements provide new insights into the structural changes and changes in the hydration behavior of HSA,revealing the dynamic process of protein purification,and providing a theoretical basis for the selection of HSA alcoholic precipitation process parameters,as well as for further studies of complex biological systems.

FT-IR Spectroscopy Applied for Surface Clays Characterization

The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, excipients or as active in drugs has largely increased these recent years. The surface clay material presents hydroxyl groups, which can link very easily water molecules. These hydroxyl groups can react with organic groups and by their vibration in the infra-red region, FT-IR can be easily used as a technical method for surface clay characterization. In this paper, we focus on the determination of Lewis and Bronsted acid sites on the clay surface, a critical review of the sample preparation, the surface characterization of bulk clay and the modified surface clay samples using FT-IR spectroscopy.

Quantitative Assessment of Amino Acid Damage upon keV Ion Beam Irradiation Through FTIR Spectroscopy

Ion beam irradiation induces important biological effects and it is a long-standing task to acquire both qualitative and quantitative assessment of these effects. One effective way in the investigation is to utilize Fourier transformation infrared （FTIR） spectroscopy because it can offer sensitive and non-invasive measurements. In this paper a novel protocol was employed to prepare biomolecular samples in the form of thin and transversely uniform solid films that were suitable for both infrared and low-energy ion beam irradiation experiments. Under the irradiation of N^＋ and Ar^＋ ion beams of 25 keV with fluence ranging from 5×10^15 ions/cm^2 to 2.5×10^16 ions/cm^2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine, methionine and phenylalanine, were evaluated and compared. The ion beam irradiation caused biomolecular decomposition accompanied by molecular desorption of volatile species and the damage was dependent on ion type, fiuence, energy and types of amino acids. The effectiveness of application of FTIR spectroscopy to the quantitative assessment of biomolecular damage dose effect induced by low-energy ion radiation was thus demonstrated.

A Study on the Surface Structures of Viscose-based Activated Carbon Fiber by FT-IR Spectroscopy and XPS

Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450 - 900℃ for 30 min, and at 600℃for 5- 30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting material, carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.

Surface Chemistry and Catalysis of Rare Earth Oxides I．A Study of the Reactivity of Surface Hydroxyls on CeO_2 and Pr_6O_（11） by FT－IR Spectroscopy

The surface chemical properties of CeO2 and Pr6O11 have been investigated with FT-IR spectroscopy. The reactivities of surface hydroxyls were tested through the reaction of CO. Surface formate species are formed on CeO2 and Pr6O11 under CO atmosphere at 200℃ . and the reaction becomcs more prevailing at higher temperatures especially for partially reduced samples. The surface formate species are produced via the reaction of CO with surface hydroxyls which was confirmed by the reaction of CO with D2-treated CeO2 and Pr6O11. The Surface formate can be oxidized to carbonate at temperatures exceeding 300 ℃, and the surface hydroxyls could be recovered as the formate species decompose or are oxidized to carbonate species. The roles played by the surface hydroxyls and surface active sites in the CO oxidation are discussed.

IR Spectroscopic Characterization of Lignite as a Tool to Predict the Product Range of Catalytic Decomposition

The catalytic pyrolysis of lignites is a technical process whose development is complex and time-consuming with the goal to maximize the yield of the desired low-volatile hydrocarbons of choice and to minimize the yield of solid residual products. Not every type of lignite is suitable for this process due to its particular chemical composition. In order to be able to predict which lignite specimen will be an especially promising raw material for the pyrolytic liberation of target products, the chemical classification by IR spectroscopic methods was investigated. MIR spectroscopy has been demonstrated to be a valuable tool to characterize the the molecular composition of lignites and to determine the concentrations of aliphatic and aromatic functional groups in lignite as well as alcoholic OH and other forms of bound oxygen. These data provide a comprehensive chemical characterization of the material and help to predict the composition of the chemical components liberated by catalytic decomposition. With a complementary NIR spectroscopic approach, a chemometric method has been developed with which the elemental com-position of the lignites can be determined in a fast and pragmatic way leading to a prediction of the product range of a theoretical pyrolytic product range. Thus, this spectroscopic investigation is a toolbox that can answer the question if the commercial exploitation of catalytic pyrolysis of a lignite sample in question will make sense without preliminary conduction of long and time-consuming testing.

FT-IR Spectroscopic Investigation of Co-adsorption of Acetonitrile and CO on Fresh Mo_2C/Al_2O_3 Catalyst

The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo2C/Al2O3 catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH3CN and CH3CH2NH2 were formed after CH3CN adsorption on the Mo2C/ Al2O3 catalyst.The appearance of a strong band at 1578 cm-1 indicates that CH3CN was reactive with hydrogen on the Mo2C/Al2O3 catalyst.

In Situ IR Spectroscopic Study on the Hydrogenation of 1,3-Butadiene on Fresh Mo_2C/γ-Al_2O_3 Catalyst

The surface species formed from the adsorption of 1,3-butadiene and 1,3-butadiene hydrogenation over the fresh Mo2C/γ-Al2O3 catalyst was studied by in situ IR spectroscopy. It is found that 1,3-butadiene adsorption on the Mo2C/γ-Al2O3 catalyst mainly forms π-adsorbed butadiene(πs and πd) and σ-bonded surface species. These species are adsorbed mainly on the surface Moδ+(0<δ<2) sites as evidenced by co-adsorption of 1,3-butadiene and CO on the fresh Mo2C/γ-Al2O3 catalyst. The IR spectrometric analysis show that hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst produces mainly butane coupled with a small portion of butene. The selectivity of butene during the hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst might be explained by the adsorption mode of adsorbed 1,3-butadiene. Additionally, the active sites of the fresh Mo2C/γ-Al2O3 catalyst may be covered by coke during the hydrogenation reaction of 1,3-butadiene. The treatment with hydrogen at 673 K cannot remove the coke deposits from the surface of the Mo2C/γ-Al2O3 catalyst.

聚乙烯微塑料对青稞幼苗生长影响的FTIR光谱研究

利用傅里叶变换红外光谱(FTIR)结合二阶导数红外光谱(SD-IR)对在富含聚乙烯微塑料环境下生长的青稞幼苗进行研究。结果显示,青稞幼苗的一维原始光谱整体相似,主要由蛋白质、糖类和脂质的吸收峰组成。在二阶导数红外光谱中,不同条件下生长的青稞幼苗在1800~800 cm^(-1)范围内的吸收峰强度和形状展现出差异。结果显示,与对照组相比,在富含聚乙烯微塑料环境下生长的青稞幼苗的多糖、蛋白质和脂质含量发生了变化。结果表明,傅里叶变换红外光谱结合二阶导数光谱能够有效监测微塑料对青稞幼苗生长的影响。

RAMAN AND IR SPECTROSCOPY OF PTCR Ba_(1-x)Pb_xTiO_3 CERAMICS

Raman and IR spectra of Nb-doped PTC Ba1-xPbxTiO3 semiconducting ceramics (x = 0,0. 28,0. 296,0. 313,0. 330,0. 370) have been measured, and mode assignments of Raman scattering frequencies and infrared absorption peaks have been made at room temperature. The influence of Pb2+ ions content on resistivity temperature characteristics and vibration spectra for the Ea1-xPbxTiO3, ceramics have been discussed,and the temperature dependence of the Raman spectra in tetragonal and cubic phases have been investigated from 25 to 340℃. The results indicated that the Raman spectra of the paraelectric phase above Curie point are obviously different from that of ferroelectric phase below Curie point are obviously different from that of ferroelectric phase below Curie point for all the samples. Curie point of each sample,which is determined by resistivity-temperature characteristic measurment, is in good agreement with the results of Raman analysis. The ferroelectric phase transition in the PTCR Bai-xPbxTiO3 ceramics belongs to a distortion or displacement transition.

Branched Polyamines Functionalized with Proposed Reaction Pathways Based on ¹H-NMR, Atomic Absorption and IR Spectroscopies

Three novel branched polyamines N,N,N’,N’-tetrakis-[3((pyridine-2-methyl)-amine) propyl]-1,4- butanediamine (1), N,N,N’,N’-tetrakis-[N-((2-methylpyridine)ethyl)propanamide]ethylenediamine (2) and N,N,N’,N’-tetrakis-[3((2-hidroxibenziliden)-amine)propyl]-1,4-butanediamine (3), were synthesized starting from 2-pyridinecarboxaldeyde with DAB-Am-4 for 1, PAMAM G0 for 2 and from salicylaldehyde with DAB-Am-4 for 3. The pathway reactions have been proposed by 1H-NMR, IR and Atomic Absorption Spectroscopy. The optimal reaction time was set by IR spectroscopy following aldehyde? peak modification. 1 and 2 were obtained as both hydrochlorides and as free amines and 3 only as free imine. These polyamines were characterized by UV-Vis, IR, 1H-NMR and 13C-NMR and Mass Spectrometry.

Studies on the Hydrogenation of Acetonitrile over Fresh Mo_2C/γ-Al_2O_3 Catalyst by In-situ IR Spectroscopy

The adsorption of acetonitrile, the co-adsorption of acetonitrile with CO, and hydrogenation of acetonitrile on fresh Mo2C/γ-Al2O3 catalyst were studied by in situ IR spectroscopy. It was found out that CH3CN exhibited strong interaction with the fresh Mo2C/γ-Al2O3 catalyst and was adsorbed mainly on Moδ+ sites of fresh Mo2C/γ-Al2O3 catalyst. Moreover, CH3CN could affect the shifting of IR spectra for CO adsorption towards a lower wave number. The IR spectroscopic study on acetonitrile hydrogenation showed that CH3CN could be easily hydrogenated in the presence of H2 on the Mo2C/γ-Al2O3 catalyst. Furthermore, it was observed that CH3 CN could be selectively hydrogenated to imines on fresh Mo2C/γ-Al2O3 catalyst. Additionally, the active sites of fresh Mo2C/γ-Al2O3 catalyst might be covered with coke during the hydrogenation reaction of acetonitrile. The treatment of catalyst with hydrogen at 673 K could not completely remove coke deposits on the surface of the Mo2C/γ-Al2O3 catalyst.

利用FTIR对苯基异氰酸酯与不同含水率纤维素反应的研究

通过FTIR红外光谱对苯基异氰酸酯与醇、水、不同含水率纤维素反应产物的研究 ,确定了产物的红外光谱吸收峰的归属。研究发现 :异氰酸酯与绝干纤维素羟基反应产物是氨基甲酸酯 ,随着纤维素含水率的增加 ,异氰酸酯与纤维素的反应越来越低 ,与水反应的比例越来越高 ;当纤维素含水率为 9 78%时 。

CO和SCN^-在高分散Pt及Pd表面异常红外光学行为的电化学现场FTIR反射光谱研究

在玻碳基底上沉积Pt和Pd，在以CO和SCN-为探针分子的电化学现场FTIR反射光谱研究中，首次观察到异常红外光学行为，其中包括吸附物种的谱带方向倒反以及谱峰强度显著增强等．

牛血清白蛋白-羟基磷灰石难溶性复合物的FT-IR光谱研究

利用富立叶变换红外光谱（ＦＴＩＲ）法对牛血清白蛋白（ＢＳＡ）羟基磷灰石［Ｃａ１０（ＯＨ）２（ＰＯ４）６］难溶性复合物的组成及ＢＳＡ与羟基磷灰石的作用方式进行了研究。结果表明，复合物中ＢＳＡ与羟基磷灰石之间存在着强烈的相互作用，这种相互作用使水溶性的ＢＳＡ进入固体羟基磷灰石的结构形成难溶性ＢＳＡ羟基磷灰石复合物。复合物具有非化学计量的性质，体现了生物矿化的特征。正是这种蛋白质与羟基磷灰石间的复杂相互作用，形成高级自组装结构，使矿化产物具有高强度和韧性。

电化学原位步进扫描时间分辨显微镜FTIR反射光谱

结合步进扫描傅立叶变换红外光谱仪和红外显微镜,建立了电化学原位步进扫描时间分辨显微镜FTIR反射光谱.采用微电极和利用纳米结构表面的异常红外效应,显著提高表面吸附物种的红外检测灵敏度和红外电极表面对极化电位的响应速度,使广泛应用的外反射型薄层红外电解池的时间常数(τ=R1Cd)从使用常规盘电极的约40ms降低到0.65ms.研究了酸性介质中CO在Pt电极上的吸附过程,谱图的时间分辨率达50μs.

BSA-羟基磷灰石可溶性复合物的FTIR光谱

利用富立叶变换红外光谱对水溶性牛血清白蛋白(BSA)羟基磷灰石复合物的组成及结构进行了研究.结果表明,其组成具有非化学计量的性质,且复合物中BSA与羟基磷灰石间存在相互作用.从而增加了羟基磷灰石在水中的溶解度.正是由于羟基磷灰石与蛋白质形成了水溶性的复合物,使羟基磷灰石在蛋白质结构的基质上成核和自组装成为可能,从而引起和促进了生物矿化过程.

微波法高度分散CuCl_2-β沸石上CO吸附的IR光谱研究

CO adsorption on β zeolite with highly dispersed CuCl 2·2H 2O was studied by IR spectroscopy. The results of XRD and 29 Si NMR indicate that CuCl 2·2H 2O is highly dispersed into β zeolite channel as a monolayer. The IR spectra of adsorbed CO on the zeolites demonstrate that two distinct types of adsorption sites exist in the zeolites, i.e ., cation and non cation exchange sites. Two simultaneous processes, solid phase ion exchange and molecular diffusion, are involved in the dispersion of CuCl 2·2H 2O.

BSA与羟磷灰石相互吸附的FTIR-ATR光谱

采用傅里叶变换红外衰减全反射(FTIR-ATR)光谱法对牛血清白蛋白(BSA)在羟磷灰石(HA)[Ca_(10)(OH)_2(PO_4)_6]表面不同时间的相互吸附作用进行了表征。在BSA溶液作用下,羟磷灰石表面的Ca^(2+)、PO_4^(3-)和OH^-离子初始的溶解和再沉淀使得BSA与HA相互作用层层叠加,在HA表面形成从表层到次表层分子都包含有吸附的BSA的覆盖层,从而加深两者之间的相互作用。经红外差谱法处理过的相关ATR数据表明,BSA与HA之间的相互作用是快速的,并随时间变化进一步加强;来自HA上PO_4^(3-)的P=O基团对蛋白质肽键的酰胺Ⅱ带(-CNH)、多肽链的甲基(-CH_3)和亚甲基(-CH_2)上氢的吸附作用要比P-O快速而且强烈。Ca^(2+)在该吸附过程中起了极其重要的作用,其快速与蛋白质肽键的羰基氧发生作用,并诱导该蛋白质二级结构由β-折叠向α-螺旋和β-转角构象转变;伴随着这一构象变化,蛋白质多肽链上大多数肽键的-C=O和H-N-活性基团从链间氢键交联中释放出来,带动众多的氢分别参与同HA表面的Ca^(2+)、PO_4^(3-)和OH^-离子的相互吸附作用,并牢牢地结合于HA表面;这对硬组织的再生起着重要作用,促进了HA的生物矿化过程。

火星进入流场特性中红外吸收光谱诊断研究

火星探索项目是我国深空探测工程的重要组成部分,“天问一号”2021年成功着陆火星,是中国航天在火星探索研究迈出的一大步。火星大气的气氛主要以二氧化碳为主,表面气压远低于地球大气,由于大气成分和进入轨道的差异,火星进入器面临的热环境同地球返回器有很大不同,其进入过程为非空气介质的高速流动,将产生严重的气动防热问题。利用电弧风洞模拟火星进入器气动加热环境,是开展火星探测防热系统设计的关键。电弧风洞模拟火星进入高温过程,其主要过程是CO_(2)主导的离解反应,并且CO等高温离解组分与火星进入器防热材料相互作用,产生的催化效应会显著影响气动热环境。利用中红外量子级联激光吸收光谱测量技术,开展电弧加热火星进入流场特性的在线定量研究。电弧加热在线诊断研究利用CO在4.5μm附近中心波长为2212.625 cm^(-1)(v″=0,R(19))的谱线,实现了对火星地面流场的高信噪比测量,采用单线-直接吸收光谱诊断技术获得了自由流静温和关键组分CO摩尔浓度的实时测量结果。典型状态下,火星进入流场自由流静温和CO摩尔组分浓度在整个运行时间内保持稳定,显示出电弧加热流场良好的稳定性。六组重复试验显示自由流静温和CO摩尔组分浓度分别在(1757±69)K和(0.189±0.027)范围内,自由流温度波动≤3.9%,CO组分浓度波动≤14.3%,证明电弧风洞建立的火星地面流场具有非常好的重复性。基于该研究发展的电弧风洞中红外激光吸收光谱诊断技术,可以为研究火星进入器气动热环境和防热材料烧蚀-催化特性提供精细化测量能力。