Diffuse Reflectance Infrared Fourier Transform Spectra of Biofilm-Containing Sediments: Influence of Sample Lyophilization and Drying Temperature

Monitoring of biofilms in sediments formed inside drinking water distribution systems is important due to their destructive activity and their degradation of water quality. The goal of this study was to examine the influence of drying mode and temperature upon sediments containing biofilms using diffuse reflectance infrared Fourier transform spectroscopy. Sediments were collected from sections of potable water pipes and dried at 22, 40, 105 degrees Celsius, or lyophilized. The presence of biofilm residues was demonstrated. Lyophilization of biofilms and drying at temperatures higher than 22 degrees Celsius affected the infrared spectra. The least invasive method involved air-drying of the biofilms at 22 degrees Celsius.     

Detection of Vibrational Spectroscopic Biomarkers of the Effect of Gold Nanoparticles on Wheat Seedlings Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

The aim of this study is to evaluate the biochemical changes in the leaves of wheat seedlings exposed to gold nanoparticles (AuNPs) nondestructively and rapidly using attenuated total reflectance Fourier transform infrared spectroscopy and laser-induced fluorescence. The 18?nm size gold nanoparticles are synthesized by citrate reduction. For analyzing the effect of gold nanoparticles on wheat seedlings, the treatment of gold nanoparticles was applied to the seedlings through roots and following the spectroscopic measurement of biochemical signatures. The laser-induced fluorescence measurement has been performed to access the effect of gold nanoparticles on the chlorophyll concentration of wheat seedlings. The decrease in the fluorescence intensity and the fluorescence intensity ratio on the treatment of gold nanoparticles indicates increase in the concentration of chlorophyll in the leaves of wheat seedlings. The attenuated total reflectance Fourier transform infrarred spectroscopy in combination with principal component analysis has been used to visualize the biochemical changes in the cellulose, hemicellulose, pectin, lignin, amino acids, proteins, and lipid of the leaves of wheat seedlings by recording infrared spectra in the region from 4000 to 400?cm^?1. Principal component analysis applied to the preprocessed infrared data clearly distinguishes the spectral variability between control and gold nanoparticle treated seedlings. The study shows that exposure of gold nanoparticles increases the concentrations of cellulose, hemicelluloses, pectin, and lignin in the leaves of wheat seedlings. The increase in these chemicals indicates the modulation of cell walls of the wheat seedlings by the gold nanoparticle treatment. The exposure to gold nanoparticles also enhances the expression of lipid and proteins in the leaves of wheat seedlings.     

裂解毛细管柱气相色谱－傅里叶变换红外光谱的剖析应用

采用裂解气相色谱－傅里叶变换红外光谱（ＰｙＧＣ／ＦＴＩＲ）技术，使用大口径毛细管柱，分析了一未知进口涂料，对其主要裂解碎片峰进行了定性，进而从特征碎片的产生推出该涂料的成分。并同常规红外光谱差减法进行了比较，结果表明ＰｙＧＣ／ＦＴＩＲ具有简便、快速、全面和无需标样等优点，有广泛的应用价值。     

傅里叶变换红外光谱和傅里叶变换拉曼光谱法无损鉴别药材的真伪

利用傅里叶变换红外（FT-IR）和近红外傅里叶变换拉曼（NIR FT-aman）光谱法对大黄（西宁大黄）与伪品大黄（华北大黄、山大黄、水根大黄）进行了无损快速的鉴别。结果表明：尽管正品大黄与伪品大黄差别较小，有大部分的化学成分有很大的相同之处，但在红外、拉曼谱图中各自的特征峰较突出，根据谱峰的强度和位置可容易地将它们区别开来。红外和拉曼光谱法相互印证，相互补充，具有快速、准确、操作简单、重复性好、不需对样品进行分离提取，可直接鉴别等特点。     

用色谱联用技术分析桂腈和溴代苏合香烯顺反异构体

应用气相色谱／红外光谱（ＧＣ／ＦＴＩＲ）、核磁共振（ＮＭＲ）等技术快速分离、鉴定了桂腈和溴代苏合香烯的顺反异构体,解决了气相色谱／质谱（ＧＣ／ＭＳ）分析时出现的保留行为不同的顺反异构体因为质谱图类似而导致谱库检索鉴别困难的问题。从而,可将保留指数与质谱数据相结合,互补各自在鉴定上的局限性。     

Cure Kinetics Study of Two Epoxy Systems with Fourier Tranform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC)

This work was aimed at the study of cure kinetics of two commercial thermosetting epoxy systems, Epikote resin 816 LV/Epikure F205 and Epikote resin 240/Epikure F205, by Fourier Tranform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The studied systems consist of a resin (A), based on a diglycidyl ether of bisphenol A and a hardener (B) based on the Isophorodiamine (IPDA) a cycloaliphatic diamine. These systems are used for the building and civil engineering industries, e.g. flooring compounds, adhesives, mortars and grouts. FTIR spectroscopy was employed to investigate the isothermal curing kinetics at 30, 50 or 70°C and DSC analysis to study the non-isothermal curing kinetics at different heating rates 2.5, 5, 10 and 20°C/min, from 20 to 300°C. A kinetic model was employed to simulate the FTIR isothermal experimental data using two kinetic rate constants and incorporating also diffusion control at high degrees of conversion. Finally, the variation of the effective activation energy with the extent of curing was estimated using isoconversional analysis of non-isothermal DSC data.     

Non-invasive Monitoring of Biochemical Response of Wheat Seedlings Toward Titanium Dioxide Nanoparticles Treatment Using Attenuated Total Reflectance Fourier Transform Infrared and Laser Induced Fluorescence Spectroscopy

Widespread commercial application of titanium dioxide nanoparticles leads to their dispersion in the environment and inevitable interaction with living organisms. Their presence necessitates the monitoring of nanoparticle interactions with plants using advanced techniques that are capable of noninvasively and sensitively estimating the changes involved in the biochemical profile. The current study aims to investigate the effects of titanium dioxide nanoparticles on biochemicals of wheat leaves using label free, nondestructive, rapid, sensitive, and advanced spectroscopic probes: laser induced fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy coupled with multivariate analysis. The fluorescence and infrared spectra of control and titanium dioxide nanoparticle treated wheat leaves were acquired in the region from 400 to 800?nm and 4000 to 485?cm^?1. The treatment of titanium dioxide nanoparticles decreases the chlorophyll content and the concentrations of cellulose, hemicellulose, xyloglucans, pectin, and lignin indicating interferences in the biosynthesis and structure of cell walls of the wheat leaves. The level of amide I, carbonyl, and methylene groups also increases following the treatment of titanium dioxide nanoparticles indicating lipid and protein peroxidation and the accumulation of carbonyl compounds. The changes in the integrated area ratios of the amide II/amide I, carbonyl/methyl, and methylene/amide II bands demonstrate disorder in the membrane integrity. This study establishes the efficiency of noninvasive, label-free, and rapid protocols based on attenuated total reflectance Fourier transform infrared and laser induced fluorescence to monitor the interactions of nanoparticles with plants at early stage of plant growth before visual signs of toxicity appear.     

Preparation and Spectroscopic,Microscopic, Thermogravimetric,and Electrochemical Characterization of Silver-Doped Cerium(IV) Oxide Nanoparticles

Silver ion-doped cerium oxide nanoparticles were prepared by polyol-based coprecipitation. Here, the impact of silver doping is evaluated on the crystallographic, optoelectronic, thermogravimetric, and redox behavior of cerium oxide nanoparticles. Spectroscopic techniques were used to characterize the phase purity, crystallinity, morphological structure, and optical and redox properties of nanoproducts. X-ray diffraction confirmed the formation of well-crystallized cerium oxide tetragonal fluorite. The optical absorption spectra and band gap energy were significantly affected following doping that was influenced by the crystalline size. Temperature production reduction investigated the influence of silver concentration on the redox properties of cerium oxide nanoparticles. These catalysts were reversible in cyclic redox reaction to 500°C, nonpyrophoric, and therefore demonstrated potential for applications for hydrogen generation for fuel cells and electrochemical biosensors.     

Investigating natural rubber composition with Fourier Transform Infrared (FT-IR) spectroscopy: A rapid and non-destructive method to determine both protein and lipid contents simultaneously

A large panel of Natural Rubber (NR) samples was characterized using Fourier Transform Infrared (FT-IR) spectroscopy in Attenuated Total Reflection (ATR) configuration. Specific vibrational bands were attributed to some non-isoprene compounds naturally present in NR composition. A rapid and non-destructive method was developed to investigate some specific functional groups contained in lipids (ester and carboxyl groups) and proteins (amides). Ester and carboxyl groups were quantified using calibration curves developed from synthetic cis-1,4-polyisoprene mixtures with either methyl stearate or stearic acid. Amide groups of proteins and peptides were found to be directly quantifiable from NR FT-IR spectra. The clonal origin and processing were found to influence the non-isoprene composition of NR. Significant correlations were found between FT-IR results and conventional chemical analyses: nitrogen content for proteins and total lipid extract.     

地鳖纤溶活性蛋白(EFP)的分离纯化、红外光谱分析及抑制鸡胚尿囊膜(CAM)血管生成研究

以传统中药材地鳖为原料, 采用匀浆、盐析、硫酸铵分段沉淀、透析和DEAE-52纤维素离子层析等纯化方法, 从其体内分离纯化得到一种纤溶活性蛋白(Fibrinolyric protein of Eupolyphaga sinensis Walker, EFP), 采用SDS-PAGE电泳法对该蛋白进行了分子量和纯度测定, 结果表明, 从地鳖中提取纯化的EFP为相对分子量为41300的单一成分, 具有明显的纤溶活性, 由蛋白质和糖的红外光谱特征吸收峰可推断EFP为一种糖蛋白. EFP对鸡胚尿囊膜新生血管生成有良好的抑制作用, 比阳性对照组(地塞米松组)对鸡胚生长发育影响要小. 地鳖虫纤溶活性蛋白组分具有抑制血管生成的作用, 有可能用于肿瘤治疗.     

Fe(II) hydroxycarbonate Fe2(OH)2CO3 (chukanovite) as iron corrosion product: Synthesis and study by Fourier Transform Infrared Spectroscopy

Fe(II) compounds were precipitated by mixing FeCl₂ · 4H₂O, NaOH and Na₂CO₃ · 10H₂O solutions and the influence of the concentration ratios R = [FeCl₂ · 4H₂O]/[NaOH] and R′ = [Na₂CO₃ · 10H₂O]/[NaOH] on the nature of the precipitates was studied. The conditions favouring the formation of chukanovite Fe₂(OH)₂CO₃ at the detriment of Fe(II) hydroxide Fe(OH)₂, often considered as the first solid forming from the Fe(II) dissolved species generated by the dissolution of steel, were determined. Chukanovite was the unique compound to form for R > 1 and R′ > 0.5. When one of these conditions was not met, that is when the amount of Fe(II) dissolved species or the amount of carbonate species was not sufficient, Fe(OH)₂ was precipitated together with chukanovite. For the smallest values of R and R′, 0.6 and 0.1, respectively, chukanovite was not obtained. However, it was demonstrated that ageing at room temperature of a carbonate-containing suspension of Fe(OH)₂ could lead to the total transformation of Fe(II) hydroxide into chukanovite. The Fe(II) compounds were analysed by ATR/FT-IR spectroscopy under inert atmosphere, since this method allowed us to distinguish unambiguously Fe₂(OH)₂CO₃ from Fe(OH)₂. As a result, chukanovite could also be identified by infrared micro-spectroscopy inside the rust layers of an archaeological iron nail extracted from a soil presenting anoxic conditions.     

Infrared spectroscopic ellipsometry (IRSE) and X‐ray photoelectron spectroscopy (XPS) monitoring the preparation of maleimide‐functionalized surfaces: from Au towards Si (111)

The IR ellipsometric technique was used to identify the surface species and to control the preparation of maleimide‐terminated surfaces. Because of higher s/n ratios for metallic substrates, the protocol was initially developed on Au surfaces, was later successfully transferred to technologically more relevant Si (111) substrates. The functionalized surfaces were achieved by electrochemical deposition of diazonium linker films and following chemical adsorption steps. Complementary XPS was also employed to detect the surface species in the process of preparation. The immobilization of different functional molecules was proven by interpreting the specific vibrational bands in IR spectra and additionally confirmed by XPS experiments. The surface homogeneity was investigated by FT‐IR synchrotron mapping ellipsometry. This work shows that the proposed protocol is an effective pathway to achieve the desired functionalized surfaces. Copyright © 2010 John Wiley & Sons, Ltd.     

Thermal fragmentation of the guanidinato aluminum amide precursor [Me2NC(NPr)2]Al(NMe2)2: An investigation of reactive species by matrix-isolation FTIR spectroscopy and time-of-flight mass spectrometry

The gas-phase thermolysis of the guanidinato aluminum amide precursor [Me₂NC(NⁱPr)₂]Al(NMe₂)₂ (1) in the oven temperature range of ambient temperatures to 600 °C has been investigated with matrix-isolation FTIR spectroscopy and time-of-flight mass spectrometry (argon as carrier gas). Precursor 1 fragments above 300 °C to form iPrCNCiPr (2) and monomeric Al(NMe₂)₃ (3m). Independent thermolysis series with 2 and the aluminum amide dimer 3d, [Al(NMe₂)₃]₂, were conducted and been used to interpret the results of the fragmentation of precursor 1. Compound 3m was present in the thermolysis range of 350–450 °C and has been identified for the first time. Through a comparison of measured FTIR spectra with the calculated spectrum of 3m (D₃ point group symmetry; B3LYP/6-31G(d) level of theory) all expected IR bands were found and could be assigned to normal modes. At thermolysis temperatures of ?500 °C signals indicative for H₂CNCH₃ (4) were found, showing that 3m fragments further at higher temperature. The thermolysis product 2 (iPrCNCiPr) withstands the higher thermolysis temperatures. From our study one can conclude that precursor 1 cleanly delivers the monomeric aluminum alane 3m, which then acts as the reactive material forming species.     

Structural and Infrared Spectroscopic Studies of Some Adducts of Divalent Metal Dihalides (MX2, M = Zn,Cd; X = CI,Br, I) with Variously Hindered Monodentate Nitrogen (Pyridine) Base Ligands (L = Pyridine, 2‐Methylpyridine,and Quinoline) of 1:2 Stoichiometry

Single crystal X‐ray structure determinations are described for a number of adducts of 1:2 MX₂:L stoichiometry, [M = divalent metal (Zn, Cd); X = halide (Cl, Br, I), L = (variously hindered) monodentate nitrogen (pyridine) base: py = pyridine, 2‐mpy = 2‐methylpyridine, quin = quinoline]: [(2‐mpy)₂ZnX₂] (X = Cl, Br) (isotypic, triclinic P , a ≈? 7.9₆, b ≈? 8.7, c ≈? 11.4 Å, α ≈? 86, β ≈? 79.3, γ ≈? 67°, Z = 2), [(2‐mpy)₂ZnI₂], [(quin)₂ZnX₂] (X = Br) (isotypic with the previously determined chloride, X = Cl, triclinic, P , a ≈? 8.7, b ≈? 9.6, c ≈? 11.1 Å, α ≈? 81, β ≈? 73, γ ≈? 72°, Z = 2); [(quin)₂ZnI₂]; [(2‐mpy)₂CdX₂], X = Br {isotypic with [(2‐mpy)₂ZnX₂], X = Cl, Br (above)}, X = I {isotypic with [(2‐mpy)₂ZnI₂] (above)}; [(quin)₂CdI₂]. A single molecule, with a four‐coordinate quasi‐tetrahedral metal atom, N₂MX₂, comprises the asymmetric unit of the structure in each of these. A one‐dimensional polymer is found for [(quin)₂Cd(μ‐Cl)₂]_(∞‖∞), similar to those recorded previously for CdX₂:py (1:2) (X = Cl, Br, I), the cadmium atom here lying on a 2‐axis in tetragonal space group P 2₁c, and the quin ligands coordinating trans in a six‐coordinate array about the cadmium, with successive cadmium atoms being linked by pairs of bridging chlorines. Adducts of MX₂:L (1:1) stoichiometry, defined for M = Cd: [(2,4,6‐trimethylpyridine)Cd(μ‐I)₂]_(∞‖∞) and [(quin)Cd(μ‐Br)₂]_(∞‖∞), are both infinite one‐dimensional polymers … (μ‐X)₂Cd(L)(μ‐X)₂Cd(L) … , with five‐coordinate trigonal bipyramidal cadmium atoms, the nitrogen donors being equatorial in the coordination spheres. The far‐IR spectra of [L₂MX₂] (L = py, 2‐mpy, quin; M = Zn, Cd; X = Cl, Br, I) are assigned and discussed in relation to the structures of the complexes.     

Release Profiles of Tricalcium Phosphate Nanoparticles from Poly(L‐lactic acid) Electrospun Scaffolds with Single Component,Core–Sheath,or Porous Fiber Morphologies: Effects on hASC Viability and Osteogenic Differentiation

Functional PLA scaffolds are created with single component, core–sheath, or porous fiber morphology and doped with TCP nanoparticles to study the release profiles for use in bone tissue engineering applications. Pharmacokinetic analyses are performed for the three different nanofibrous structures after doping with TCP. Results indicate that single component and porous fiber scaffolds exhibit an initial‐burst release profile whereas core–sheath fibers show a steady release. All scaffolds are then seeded with human adipose‐derived stem cells (hASC), which remain viable and continue proliferation on all nanofibrous morphologies for up to 21 d. Osteogenic differentiation of hASC and cell‐mediated calcium accretion are largest on porous fibers.