FT-Raman spectroscopy: A positive means of evaluating the impact of whale bone preservation treatment

The degreasing methods currently used for osteological collections are not always completely satisfactory. Numerous natural history museums encounter the problem of grease seeping to the surface of bones. FT-Raman spectroscopy was used to characterise cetacean bones, before and after degreasing treatment, in order to evaluate the efficacy of treatment and the impact thereof on bone constituents. The Raman spectra made it possible to monitor the changes in the main bone constituents: the mineral component with the apatite band at 960 cm⁻¹, the organic component with the collagen amide III band at 1270 cm⁻¹ and fat with the lipid CH₂ band at 2850 cm⁻¹. The band associated with lipids decreased and even disappeared with degreasing treatment containing chlorinated solvents. This type of treatment enables fat to be extracted both from the surface and from the bone core; however, it debases the organic component of bone by denaturing collagen. Alternative types of treatment (acetone or enzyme baths) were tested over a limited period, which did not enable their true efficacy to be demonstrated. During the alternative treatments, no bone degradation was observed. Only the acetone solution was able to extract fat, though only from the surface.     

FT-Raman spectroscopy of the reaction of polybutadiene with mercapto-thiadiazoles

Mercapto-thiadiazoles having potential anti-wear behaviour are reacted with polymers with existing viscosity index-improving properties in order to produce materials which may find a use as multifunctional lubricant additives. 2,5-Dimercapto-1,3,4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole and 2-methyl-5-mercapto-1,3,4-thiadiadiazole were reacted with low MW polybutadiene containing vinyl-1,2, cis-1,4 and trans-1,4 (C=C) groups. The reactions were monitored using FT-Raman spectroscopy in order to determine quantitatively the consumption of the individual structural units when reacted with thiadiazoles. 2,5-Dimercapto-1,3,4-thiadiazole reacted readily with the polybutadiene, achieving 80% reaction within a few hours. The thiadiazole reacted selectively with the order of addition being cis>vinyl>trans. 2-Amino-5-mercapto-1,3,4-thiadiazole and 2-methyl-5-mercapto-1,3,4-thiadiazole were found to react more slowly and hence to a lesser extent (40 and 25%, respectively) over a similar time scale.     

A study of amber and copal samples using FT-Raman spectroscopy.

FT-Raman spectra were collected from fossil resins originating from a variety of geographical locations. The spectral profiles of most of the fossil resins could be related to modern resins containing diterpenoid components with predominantly labdane skeletons. The spectra collected from the fossil resin sample from Borneo differed from other fossil resins and was found to contain triterpenoid components. The differences in the spectral profile of fossil resins containing diterpenoid components are shown to relate to differences in level of maturation rather than geographical origin. FT-Raman spectra of fossil resins cannot be used to distinguish source although the degree of maturation can be used as an indicator to narrow the range of possible geographical origins.     

Application of FT-Raman spectroscopy for the characterisation of new functionalised macromers

Fourier transform (FT)-Raman spectroscopy has been used extensively for the characterisation of polymers, especially polymers containing functional groups. New macromers with unsaturation have been synthesised using a living anionic polymerisation process. The reactions of living polystyryllithium with butadiene, followed by the capping reaction with mono or tri-functional chlorosilane norbornene were investigated. Characterisations by NMR and GPC have confirmed the formation of these macromers, but FT-Raman spectroscopy has revealed interesting information related to the isomerisation of the butadiene spacer in the polymer backbone.     

Monitoring the kappa number of bleached pulps based on FT-Raman spectroscopy

Cellulose - A new strategy was proposed to determine the Kappa number of bleached Eucalyptus globulus kraft pulps based on FT-Raman spectroscopy. Before modeling, smoothing (Savitzky-Golay),...     

FT-Raman spectroscopy of lichens on dolomitic rocks: an assessment of metal oxalate formation

The FT-Raman spectra of five epilithic lichen taxa growing on dolomite and magnesium-rich carbonate rocks have been analysed and interpreted for the key molecular marker bands associated with calcium oxalate monohydrate (whewellite), calcium oxalate dihydrate (weddelite) and magnesium oxalate dihydrate. From the results, it can be concluded that the biomineral product of lichen biodeterioration involves the calcareous part of the substratum only; no trace of magnesium oxalate has been found in the Raman spectra. Two of the species, Lecanora sulfurea and Aspicilia calcarea, produce calcium oxalate monohydrate exclusively, but Dirina massiliensis f. sorediata, D. massiliensis f. massiliensis and Tephromela atra produce significant quantities of the dihydrate. An explanation is advanced for the exclusive accumulation of calcium oxalate into the lichen thallus despite the significant presence of magnesium ions.     

Characterization of the surface properties of xylan by FT-Raman spectroscopy and wicking technique

Using FT-Raman spectroscopy, column wicking technique and the equations of Washburn as well as van Oss et al., the surface properties of xylan, the main component in hemicelluloses, has been characterized and estimated. Raman spectrum showed that xylan has been structured by acetyl group and methyl-bonded glucurono group. Obtained results show that the surface free energy of xylan is higher in comparison with literature reported values for cellulose because the former has a larger Lifshitz–van der Waals component than the latter. However, xylan has been found to have very smaller polarity and orientation data than that of cellulose.     

Application of FT-Raman spectroscopy to the study of the benzotriazole inhibition of acid copper corrosion

The initial stages of the corrosion protection of copper surfaces by benzotriazole in sulfuric acid solution are investigated using FT-Raman SERS and X-ray photoelectron spectroscopy. Spectra are measured in the presence of ppm levels of inhibitor on a copper surface in situ. The dependence of the adsorbate spectra on the electrode potential, solution pH, oxidation/reduction cycles and time is observed. Good spectra are obtained from copper electrodes prepared using in situ oxidation/reduction cycling in low pH sulfate solutions free from chloride at negative potentials.     

A study of binary adsorption of aromatics in completely siliceous zeolite ZSM-5 by FT-Raman spectroscopy

In the present work, binary adsorption of p-xylene and toluene in completely siliceous zeolite ZSM-5 was examined by FT-Raman spectroscopy in combination with powder X-ray diffraction. The results indicate that at total loadings of < or = 4 molecules per unit cell (u.c.) both p-xylene and toluene molecules prefer to reside at the intersections of straight and zigzag channels. The structure of the sorbate/sorbent complexes likely belongs to orthorhombic. At high loadings of 7 and 8 molecules/u.c., the framework of the zeolite transforms to another orthorhombic phase. In this high-loaded phase, toluene molecules are distributed evenly in both the channel intersection and the midsection of straight channel. Although p-xylene has access to both the channel intersection and the zigzag channel, it does show a slight preference for the channel intersection. The adsorptive behavior of these aromatics at intermediate total loadings of 5 and 6 molecules/u.c. is more complicated because the zeolitic framework is a mixture of two different orthorhombic phases.     

Characterization of the surface properties of persimmon leaves by FT-Raman spectroscopy and wicking technique

To fit the request of developing new biomaterials using persimmon leaves as raw material, this paper reported the surface free energy and related components, e.g. the Lifshitz-van der Waals and Lewis acid-base components for persimmon leaves estimated by means of the column wicking technique. Considering this natural material might be varied of its properties with growing area, a characterization of it was initially performed by applying the FT-Raman spectroscopy. Based on the determined results, persimmon leaves have greater surface free energy, gammaS, than cellulose though it has been found rich in this component, e.g. of about 68.28%. Moreover, it was further observed that the persimmon leaves have great Lewis acid-base interactions component, gammaS(AB), contributed by the Lewis acid component, gammaS+. This suggests that the persimmon leaves are available to convert to new biomaterials expected forms.     

FT-Raman, FTIR and surface-enhanced Raman spectroscopy of the antiviral and antiparkinsonian drug amantadine

FT-Raman, FTIR and surface-enhanced Raman spectroscopy (SERS) are applied to the vibrational characterization of the antiviral and antiparkinsonian drug amantadine. SERS spectroscopy is employed for the first time for characterizing the interfacial behavior of this molecule and to study its interaction with colloidal silver. The comparison of SERS spectrum with the Raman spectra of amantadine in solid state and in aqueous solution reveals remarkable changes attributed to the interaction of the drug with the metal through the unprotonated amino group and the formation of a self-assembled amantadine layer on the metal surface. A tentative assignment of the obtained vibrational spectra is carried out on the basis of the vibrational spectra of the structurally related molecules adamantane and tert-buthylamine and the ab initio calculations accomplished for amantadine.     

Two-dimensional correlation spectroscopy and multivariate curve resolution for the study of lipid oxidation in edible oils monitored by FTIR and FT-Raman spectroscopy

Accelerate oxidative degradation of six vegetable oils was monitored using FTIR and FT-Raman spectroscopy. Two-dimensional correlation spectroscopy and multivariate curve resolution alternating least squares (MCR-ALS) were applied to the analysis of the data. The use of hetero-spectral two-dimensional correlation of FTIR and FT-Raman data allowed the use of well established band assignments to interpret less clearly assigned spectral features. With a moving window approach it was possible to obtain simplified two-dimensional correlation maps and to detect compounds evolving with different kinetic. Simultaneous analysis of the oxidation experiments of the six different oils monitored by both spectroscopic techniques was performed using MCR-ALS. Although a complete resolution of the data was not possible, the spectral changes occurring during the oxidative degradation of the oils were described with a five-component model. The two fundamentally different chemometric approaches lead to coincident results.     

Vibrational characterization of L-leucine phosphonate analogues: FT-IR, FT-Raman, and SERS spectroscopy studies and DFT calculations

This study reports the Raman (FT-Raman) and absorption infrared (FT-IR) spectra, based on calculated wavenumbers and normal modes of vibrations, of the following compounds: L-Leu-D-NH-CH(Me)-PO(3)H(2) (LI), L-Leu-NH-C(Me)(2)-PO(3)H(2) (LII), L-Leu-D-NH-CH(Et)-PO(3)H(2) (LIII), L-Leu-L-NH-CH(Et)-PO(3)H(2) (LIV), L-Leu-L-NH-CH(EtOH)-PO(3)H(2) (LV), L-Leu-NH-C(Me)(Et)-PO(3)H(2) (LVI), L-Leu-L-NH-CH(PrA)-PO(3)H(2) (LVII), L-Leu-L-NH-CH(c-Pr)-PO(3)H(2) (LVIII), L-Leu-L-NH-CH(t-Bu)-PO(3)H(2) (LIX), L-Leu-L-NH-CH(BuA)-PO(3)H(2) (LX), L-Leu-L-NH-CH(c-Bu)-PO(3)H(2) (LXI), and L-Leu-L-NH-C(Adm)-PO(3)H(2) (LXII). The equilibrium geometries and vibrational wavenumbers were calculated using density functional theory (DFT) at the B3LYP, 6-311++G** level using Gaussian 03, Raint, GaussSum 0.8, and Gar2ped software. We briefly compare and analyze the experimental and calculated vibrational wavenumbers in the range 4000-400 cm(-1). In addition, the Raman wavenumbers are compared to those from the surface-enhanced Raman scattering (SERS) spectra for the phosphono analogues of l-leucine (l-Leu) adsorbed on a colloidal silver surface in an aqueous solution. The geometries of these molecules etched on the silver surface were deduced from observed changes in both the intensity and broadness of Raman bands in the spectra of the bound versus free species. For example, LVI appears to adsorb onto the colloidal silver particles mainly through the amine group and amide bond, which assists in the adsorption process, whereas LII shows strongly enhanced SERS bands due to the rocking, twisting, and stretching vibrations of the N(amid)C(sg)(Me)(2)P fragment, suggesting that this peptide's interaction with the silver surface occurs mainly via this fragment. On the other hand, the most dominant SERS bands of LIII and LIV due to the P═O bond stretches reflect P═O···Ag complex formation.     

A comparative study of diesel analysis by FTIR, FTNIR and FT-Raman spectroscopy using PLS and artificial neural network analysis

Diesel properties determined by ASTM reference methods as cetane index, density, viscosity, distillation temperatures at 50% (T50) and 85% (T85) recovery, and the total sulfur content (%, w/w) were modeled by FTIR-ATR, FTNIR, and FT-Raman spectroscopy using partial last square regression (PLS) and artificial neural network (ANN) spectral analysis. In the PLS models, 45 diesel samples were used in the training group and the other 45 samples were used in the validation. In the ANN analysis a modular feedforward network was used. Sixty diesel samples were used in the neural network training and other 30 samples were used in the validation. Two different ATR configurations were compared in the FTIR, a conventional (ATR1) and an immersion (ATR2) cell. The ATR1 cell presented the best results, with smaller prediction errors (root mean square error of prediction, RMSEP). The comparison of the three PLS models (FTIR-ATR1, FTNIR, and FT-Raman) shows that reasonable values of R² and RMSEP were obtained by the FTIR-ATR1 and FTNIR models in the evaluation of density, viscosity, and T50. The PLS/FT-Raman models presented reasonable results only for the T50 property. None of the techniques was able to generate suitable PLS calibration models for the determination of sulfur content. The ANN/FT-Raman models presented the best performances, with all models presenting R²-values above 85% some of them with RMSEP values significantly smaller than those obtained with FTIR-ATR and FTNIR. The ANN/FT-Raman and ANN/FTIR-ATR1 models were able to estimate the total sulfur content of diesel with 0.01% (w/w) accuracy.     

Investigation of intermolecular interactions in solutions by means of millimeter-wave spectroscopy 4. Negative and positive hydration in aqueous solutions of urea

Measurements have been made of the absorption of EHF radiation ( 5 cm^–1) by aqueous solutions of urea at 20–70°C, over the entire interval of urea solubility. Excess absorption has been found in comparison with the additive magnitude, and this has been attributed to an increase in the fraction of water molecules in the solution with rotational degrees of freedom. A model has been proposed for the hydration of urea, based on the concept of inhomogeneity of the hydrate shell of urea: stabilization of the structure of water under the influence of carbonyl oxygen and H_cis atoms (positive hydration) and a simultaneous breakdown of the structure of water in the region of two H_trans atoms that have approached to a distance of 2.14 » (negative hydration).For Previous Communication, See [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 314–320, February, 1990.     

Ion cyclotron resonance spectrometry. A means of evaluating ‘kinetic shifts’

Ion Cyclotron Resonance Spectrometry Is Proposed As The Method For Evaluating ‘Kinetic Shifts.’ The Proposal Is Tested By A Comparison Of The Appearance Potentials For Some Simple Cleavage Reactions With Those For Some Cleavage And Rearrangement Fragmentations In Benzene, Benzonitrile, Anisole, Aniline And Cubane.     

肥皂草素Saporin-S6二级结构的圆二色光谱及激光喇曼光谱法表征

肥皂草素是从石竹科植物肥皂草 (Saponaria officinalis)的种子中提取的一种单链核糖体失活蛋白(sc RIP) ,它可选择性地作用于真核细胞的核糖体和原核细胞裸露的 r RNA使其脱嘌呤 ,从而抑制蛋白质的合成 [1] .核糖体失活蛋白种类繁多 ,性质稳定 ,制备安全简便 ,与单克隆抗体结合后所制备的单链免疫毒素在肿瘤治疗和骨髓移植等方面有着广泛的应用前景[2 ] .Stirpe等[1] 首次分离到肥皂草毒蛋白 ,并证明其为不含糖基的单链 RIP.SO-6是种子中含量最丰富的核糖体失活蛋白 [3] ,且具有特殊的稳定性[4 ] .肥皂草素在医学上的应用十分广泛 ,…     

A study of the conformers of the N,N-diethyl-N-methyl-N-propylammonium ion by means of infrared spectroscopy and DFT calculations

The infrared absorption spectrum of the N,N-diethyl-N-methyl-N-propylammonium (DMPA) bis(fluorosulfonyl)imide (FSI) ionic liquid is measured as a function of temperature between 165 and 307 K. In the frequency range between 900 and 1070 cm⁻¹ only the cation gives rise to infrared bands. A conformational analysis of DMPA is performed by means of DFT calculations at the B3LYP/6-31G** level. The comparison of the experimental and calculated spectra provides evidence that the lowest energy conformers coexist in the liquid. Experimentally, we find that the energy difference between the most stable rotamer and the next energy conformers is only 1.56 ± 0.05 kJ/mol, in good agreement with the calculated value. Finally, we show that in the solid state only the most stable isomer is retained.     

Diagnostic Raman spectroscopy for the forensic detection of biomaterials and the preservation of cultural heritage

This paper reviews the contributions of analytical Raman spectroscopy to the non-destructive characterisation of biological materials of relevance to forensic science investigations, including the sourcing of resins and the identification of the biodegradation of art and archaeological artefacts. The advantages of Raman spectroscopy for non-destructive analysis are well-appreciated; however, the ability to record molecular information about organic and inorganic species present in a heterogeneous specimen at the same time, the insensitivity of the Raman scattering process to water and hydroxyl groups, which removes the necessity for sample desiccation, and the ease of illumination for samples of very small and very large sizes and unusual shapes are also apparent. Several examples are used to illustrate the application of Raman spectroscopic techniques to the characterisation of forensic biomaterials and for the preservation of cultural heritage through case studies in the following areas: wall-paintings and rock art, human and animal tissues and skeletal remains, fabrics, resins and ivories.