二维傅里叶变换红外(2D FTIR)相关光谱技术研究聚羟基丁酸酯(PHB)的熔融与结晶

应用新型二维傅里叶变换红外(2DFTIR)相关光谱研究细菌合成聚羟基丁酸酯(PHB)在升温时的预熔行为以及降温后的重结晶过程.在25～220℃的变温过程中测得动态红外光谱.着重讨论了在热力学干扰导致红外谱图中羰基峰(1700～1770cm^-1)和醚键(1230～1310cm^-1)吸收强度的波动.结果表明,这种影响来自样品中PHB的结晶态和非晶态之间的相态变化.二维谱图分析表明,在热熔过程中,结晶态的消失并不同时引起完全非晶态的出现,暗示在分子排列高度有序的晶态和非晶态之间存在某种中间态,PHB晶体向非晶态转变时必须经过一个预熔过程.在红外谱图上这个中间态很可能对应着由二维分析显示出来的位于1730cm^-1的吸收峰.同时,在PHB熔体从非晶态逐渐生成晶体的过程中也探测到了中间态的存在.     

丁基黄药在CuO表面吸附的二维连续在线原位ATR-FTIR光谱研究

运用连续在线原位衰减全反射傅里叶变换红外光谱(ATR-FTIR)技术测定了纳米CuO表面对丁基黄药的吸附行为.在FTIR谱图中发现有峰的红移现象,吸收峰由1200 cm-1偏移到1193 cm-1,用超纯去离子水脱附,峰强度只有微小的变化,可判断丁基黄药在CuO表面发生了很强的化学吸附.通过对吸附行为进行二维(2D)红外光谱分析,分辨出吸附过程中光谱强度的变化顺序.二维异步相关光谱测定结果表明,1265 cm-1处振动吸收峰最先引起光谱强度的变化,1265 cm-1处吸收峰可归因为表面反应生成的双黄药和黄药分子聚集体的复合峰.根据1200 cm-1处黄药特征吸收峰强度的变化,进行吸附动力学模拟,得出CuO对丁基黄药的最大吸附量为529 mg·g-1,且吸附符合拟二级吸附动力学过程.     

丁基黄药在CuO表面吸附的二维连续在线原位ATR-FTIR光谱研究

运用连续在线原位衰减全反射傅里叶变换红外光谱(ATR-FTIR)技术测定了纳米CuO表面对丁基黄药的吸附行为. 在FTIR 谱图中发现有峰的红移现象,吸收峰由1200 cm^-1偏移到1193 cm^-1,用超纯去离子水脱附,峰强度只有微小的变化,可判断丁基黄药在CuO表面发生了很强的化学吸附. 通过对吸附行为进行二维(2D)红外光谱分析,分辨出吸附过程中光谱强度的变化顺序. 二维异步相关光谱测定结果表明,1265 cm^-1处振动吸收峰最先引起光谱强度的变化,1265 cm^-1处吸收峰可归因为表面反应生成的双黄药和黄药分子聚集体的复合峰. 根据1200 cm^-1处黄药特征吸收峰强度的变化,进行吸附动力学模拟,得出CuO对丁基黄药的最大吸附量为529 mg·g^-1,且吸附符合拟二级吸附动力学过程.     

Eu3＋对DMPC人工膜脂双层主相变温度的影响

利用付里叶变温红外光谱和核磁共振谱研究了Eu     

丙烯在MoO_3和γ-Bi_2MoO_6上选择(氨)氧化副产物形成机理的化学捕获和DRFTIR研究

采用以H_2、NH_3及CH_3I为捕获剂的化学捕获方法研究了丙烯在MoO_3和γ-Bi_2MoO_6上的吸附.结果表明,丙烯吸附时通过在Mo~(2+)和邻近晶格氧上断裂C=C及C—C键发生碳链碎片化,导致C_1、C_2的含氧或含氮副产物的形成.以DRFTIR光谱研究了较低温度下丙烯在γ-Bi_2MoO_6上吸附和反应时形成的表面物种,175℃的实验结果与化学捕获实验一致。而50℃的实验结果与Grasselli等提出的丙烯选择氧化机理吻合.     

傅里叶变换红外光谱分辨率与氯仿测量精度的关系

测量不同分辨率下、不同浓度氯仿气体的傅里叶变换红外光谱（FTIR）．利用美国环境保护局（EPA）数据库中的数据,通过最小二乘拟合得到不同分辨率下的氯仿浓度,以及线性拟合度和相对误差．分辨率的大小对其计算精确度有一定的影响．选择合适的分辨率对于提高化合物的精确度至关重要．     

聚乙烯醇与溶菌酶的相互作用及其对溶菌酶构象的影响

在生理条件下, 使用凝胶过滤色谱、荧光光谱法、差示扫描量热分析和傅里叶变换红外光谱法(FT-IR)研究了溶菌酶与聚乙烯醇(PVA)的相互作用. 结果表明PVA与溶菌酶结合形成复合物, 在它们的相互作用过程中, 溶菌酶酪氨酸的发射荧光部分被猝灭, 但是, 相互作用并没有改变酪氨酸的微环境; 差示扫描量热分析结果表明, 溶菌酶与PVA之间的相互作用没有破坏溶菌酶的高级结构; 进一步使用红外光谱法结合可增强分辨率的傅里叶去卷积技术和高斯曲线拟合技术共同用于对溶菌酶与PVA复合物冻干粉中溶菌酶酰胺I带的定量分析, 发现冻干粉溶菌酶分子中与分子间相互作用相关的β-折叠组分含量减少了, 但是, 用于衡量冻干状态蛋白质结构完整性的α-螺旋组分含量没有降低. 活性分析结果进一步确认, PVA与溶菌酶的相互作用没有破坏溶菌酶的三级结构.     

连续在线原位ATR-FTIR技术测定介孔CuAl2O4对黄药的吸附

以丁胺和正十二醇为混合模板剂, 采用共沉淀法制备了介孔纳米CuAl₂O₄. 用X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、N₂吸附-脱附对产物的结构进行了表征. 采用连续在线原位衰减全反射傅里叶变换红外(ATR-FTIR)光谱技术研究了水溶液中丁基和辛基黄药在介孔CuAl₂O₄表面的吸附. 随着吸附时间的延长,1200 和1040 cm^-1两处黄药特征峰的高度逐渐增加, 根据1200 cm^-1处C-O-C伸缩振动峰的变化来评价黄药在CuAl₂O₄表面的吸附动力学过程. 结果表明, 介孔纳米CuAl₂O₄对黄药有很强的吸附能力, 在100 min 的时间内, CuAl₂O₄样品对丁基和辛基黄药的吸附量分别达到了236 和300 mg·g^-1, 且属于化学吸附. 对实验数据进行理论模拟, 发现吸附过程更接近于拟二级吸附动力学方程.     

化学氧化对多孔硅表面态和光致发光的影响

自1990年英国科学家Canham发现室温下多孔老（poroussilicon缩写为PS）的可见光区光致发光以来，在世界范围内迅速形成了一股强大的多孔硅研究热．硅是间接禁带半导体．禁带宽度为1．11eV，不可能在可见区发光．对于多孔硅在可见区的强烈荧光发射及其形成，Canham和Lehamm等分别建议可用量子线的尺寸限制效应未解释[1,2]．但Tsai和Hance等用FTIR研究经过后处理的多孔老样品[3]，认为多孔硅的发光与表面的硅氢化物相关，并提出硅的二氢化物SiH2的浓度与荧光强度相关．关于多孔硅的发光机制，还有非晶态发光[4]等说法．因止匕多孔硅的发…     

浓度分段模型应用于人体血清葡萄糖的FTlR/ATR光谱分析

利用傅立叶变换红外光谱（ FTlR）和衰减全反射（ ATR）技术,建立了人血清葡萄糖的快速定量分析方法。根据葡萄糖水溶液与纯净水差谱得到葡萄糖的指纹吸收波段（1200~900 cm-1）,分别在全谱（4000~600 cm-1）和指纹波段建立偏最小二乘法（ PLS）模型,指纹波段的预测效果明显好于全谱。选择指纹波段后,提出一种根据浓度分段分别建模然后进行组合的建模方法。按照全部样品、低浓度样品、高浓度样品分别建立模型后,根据3个模型进行综合决策。应用独立的检验集对样品进行测试表明,按葡萄糖浓度范围分段建立组合模型的预测效果优于基于全部样品建模的预测效果。对于分段阈值附近的样本,低浓度和高浓度模型的预测效果差别不大。浓度分段组合模型的预测均方根偏差（ RMSEP）和预测相关系数（ Rp ）分别为0.732 mmol/L和0.948。     

羟基磷灰石与牛血清白蛋白相互作用的原位红外光谱研究

应用原位(in situ)全反射红外光谱研究牛血清白蛋白在电化学法制备的羟基磷灰石表面的吸附和成键行为, 探索电化学法制备的HA生物材料/生物环境界面过程和生物相容性的微观本质.     

Thermal Analysis Studies on Human Skin and Skin Barrier Modulation by Fatty Acids and Propylene Glycol

The thermal behaviour of human stratum corneum (SC) with various hydration levels was studied using differential thermal analysis DSC within the temperature range of –130 to 120°C. SC containing 20% water, resembling the intact condition, shows thermal transitions at around –20°C (representing water in skin), –10, 40, 70°C (representing skin lipids), 85°C (representing protein-associated lipids) and 100°C (representing skin protein). Dehydration of SC causes the transitions at –20 and 100°C to be invisible. Lipid extraction followed by dehydration eliminates all transitions. Further hydration produces a transition of water at around 0°C with a huge change in enthalpy. The perturbation effects of penetration enhancers fatty acids (FA) and propylene glycol (PG) were studied using DTA on SC after pretreatment with PG alone and FA/PG. The application of PG alone shifted the transitions at 70 and 85°C to lower temperatures. Additionally, the application to dehydrated stratum corneum removes the transitions at –10°C. Saturated fatty acids, e.g. nonanoic and decanoic acids, exert barely noticeable effects on the thermal behaviour of SC suggesting that they easily mix with the skin lipids. Thermal analysis also revealed that the cis-9- and 13-isomers of octadecenoic acid (monounsaturated fatty acids) form a separate domain containing mostly the pure fatty acids within the SC lipids and suppress the lipid transitions at 70/80°C. Polyunsaturated fatty acids linoleic and -linolenic acids — form separate domains but do not completely suppress the SC lipid transitions at 70/80°C as monounsaturated acids do. This study suggests different ways of perturbation by various fatty acids.This revised version was published online in November 2005 with corrections to the Cover Date.     

ATR-FTIR法在皮革产品中的应用

目前市售皮革分为动物皮革和人造革两类.皮革是动物皮经加工后制成,具有动物皮肤特点.人造革也称假皮革是指合成革或外观貌似真皮实际上由化工原料人工合成的产品,其本身不是动物皮.怎样鉴别真皮与人造革方法有很多,如手摸法、眼看毛孔花纹等.在日常消费中,由于市场上有的皮革产品在生产过程中在表面涂了一层有机材料以及其它处理,普通消费者单凭借手感和经验目测来判断,往往不容易辨别真假.随着人们消费皮革制品的需求增加以及市售皮革制品.在有大量难辨真伪的仿皮革的人造革制品,因此鉴别各行业中的皮革受到越来越多的关注.本文运用ATR-FTIR技术对皮革材料的结构成分进行分析,依据不同物质所得到的谱图不同,就能准确、快速地分辨真皮革和人造革.     

Detection of molecular processes in the intact retina by ATR-FTIR spectromicroscopy

We used Fourier transform infrared spectromicroscopy in the attenuated total reflection configuration to study biochemical events associated with the response to light of an intact retina. We show that the technique is suitable for the detection in real time of molecular processes occurring in rod outer segments induced by light absorption. Two-dimensional correlation analysis was applied to the identification and interpretation of specific spectral changes associated to the evolution of the system. The technique allows us to observe an extensive protein translocation, which we interpret as arising from the release of transducin from the disk membrane and its redistribution from the outer segment towards the inner segment of rod cells. These results are in full agreement with our current understanding of retinal physiology and validate the technique as a useful tool for the study of complex molecular processes in intact tissue. Figure Spectral changes in the mid infrared region following exposure of an intact retina to light     

Interactions between a skin penetration enhancer and the main components of human stratum corneum lipids

The study employed isothermal titration calorimetry (ITC) technique to investigate the interactions between a skin penetration enhancer, laurocapram, and three representatives of the human stratum corneum (SC) intercellular lipids, i.e., ceramide-3, cholesterol and behenic acid. Experiments were performed using a TAM2277 (Thermometric AB, Sweden) calorimeter. Results showed that, firstly, two laurocapram molecules were bound to one ceramide-3 molecule in propylene glycol solution. The binding was enthalpy-driven and system entropy decreased after binding. Secondly, the binding ratio between cholesterol and laurocapram molecule was one to one. It was mainly an entropy-driven process, suggesting the ordered cholesterol molecules in SC lamella were disturbed by the introduction of laurocapram. Hydrogen bonding might be the main force of the binding. The three different interaction modes showed that the chemical enhancers selectively interacted with the components of SC lipids so that the SC can still retain its barrier function.     

Interaction of Antiseptic Compounds with Intercellular Lipids of Stratum Corneum

The interaction between three kinds of antiseptic compounds and components of intercellular lipids in the stratum corneum was characterized in terms of thermodynamics at pH 7.5 and 25°C, and the different mechanisms used to penetrate the stratum corneum were clarified. Anionic surfactants such as benzalkonium chloride and benzethonium chloride mainly bound to cholesterol (CH) and cholesterol sulfate with high affinity (10⁵–10⁶ M⁻¹) to extract endogenous CH from the stratum corneum and penetrated through the intercellular route. Chlorhexidine gluconate also bound to CH and accumulated in the stratum corneum without removing endogenous CH. An amphoteric surfactant of dodecyldiaminoethylglycine hydrochloride seemed to be incorporated into the lipid bilayer and bound to ceramide with its polar end close to the lipid polar heads by hydrophobic interaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

ATR-FTIR在研究环境固液微界面吸附过程中的应用

微界面吸附过程是许多环境微界面反应的初始步骤或关键步骤。通过原位分析方法实时研究环境微界面吸附过程,可以获得更直接的界面反应信息和更可靠的反应机制证据,对于认识污染物在环境中分配转化和迁移传输规律有着重要意义。衰减全反射红外光谱技术由于其独特的采样原理、简便的制样方法和广泛的适应性,正逐渐成为研究微界面反应的一个有力工具。本文在简要介绍原位衰减全反射红外光谱的技术原理的基础上,综述其在环境微界面吸附过程,尤其是矿物-水界面吸附过程中的应用,并探讨其在环境微界面过程研究中的发展前景。     

Influence of the level of cholesteryl sulfate in the solubilization of stratum corneum lipid liposomes by sodium dodecyl sulfate

 The role played by cholesteryl sulfate (Chol-sulf) in the solubilization of liposomes modeling the stratum corneum (SC) lipids by sodium dodecyl sulfate (SDS) was studied. We determined the surfactant-to-lipid molar ratios and the bilayer/aqueous phase surfactant partition coefficients of this interaction by varying the proportion of Chol-sulf, the relative proportions of the others lipids remaining constant. These parameters were determined by monitoring the changes in the static light scattering of the system during solubilization. The fact that the free surfactant concentration was always similar to its critical micelle concentration indicates that the liposome solubilization was mainly ruled by the formation of mixed micelles. The SDS ability to saturate and solubilize SC liposomes decreased as the proportion of Chol-sulf in the bilayers increased until a minimum was reached for a Chol-sulf proportion of about 15%. Inversely, the SDS partitioning into liposomes (or affinity with these bilayers) increased as the proportion of Chol-sulf increased until a maximum was reached at similar Chol-sulf proportions (10–15%). Hence, in these Chol-sulf proportions (similar to that existing in the intercellular lipids, which was 10%) the ability of SDS molecules to interact with liposomes exhibits a minimum despite their enhanced partitioning into liposomes. These effects may be related to the reported dependencies of the level of Chol-sulf on the abnormalities in the skin barrier function and on the SC intercellular cohesion. Received: 12 October 1999 Accepted: 20 January 2000     

Encapsulation of Vitamin C by Glycerol-Derived Dendrimers,Their Interaction with Biomimetic Models of Stratum corneum and Their Cytotoxicity

Vitamin C is one of the most sensitive cosmetic active ingredients. To avoid its degradation, its encapsulation into biobased carriers such as dendrimers is one alternative of interest. In this work, we wanted to evaluate the potential of two biobased glycerodendrimer families (GlyceroDendrimers-Poly(AmidoAmine) (GD-PAMAMs) or GlyceroDendrimers-Poly(Propylene Imine) (GD-PPIs)) as a vitamin C carrier for topical application. The higher encapsulation capacity of GD-PAMAM-3 compared to commercial PAMAM-3 and different GD-PPIs, and its absence of cytotoxicity towards dermal cells, make it a good candidate. Investigation of its mechanism of action was done by using two kinds of biomimetic models of stratum corneum (SC), lipid monolayers and liposomes. GD-PAMAM-3 and VitC@GD-PAMAM-3 (GD-PAMAM-3 with encapsulated vitamin C) can both interact with the lipid representatives of the SC lipid matrix, whichever pH is considered. However, only pH 5.0 is suggested to be favorable to release vitamin C into the SC matrix. Their binding to SC-biomimetic liposomes revealed only a slight effect on membrane permeability in accordance with the absence of cytotoxicity but an increase in membrane rigidity, suggesting a reinforcement of the SC barrier property. Globally, our results suggest that the dendrimer GD-PAMAM-3 could be an efficient carrier for cosmetic applications.     

Spectral characteristics of ethylene sorbed by silver-containing ionic liquids studied by in situ ATR-FTIR spectroscopy

The spectral characteristics of ethylene absorbed by ionic liquids (ILs) containing silver ions were studied by in situ ATR-FTIR spectroscopy at high pressure. Three different states of ethylene were observed based on the band shift of out-of-plane bending vibrations (ωCH₂) due to van der Waals interactions, hydrogen bonds, and π-complex formation with silver ions. Thus, ethylene can be used as an IR-sensitive probe molecule for characterizing interactions with ILs and other substances.