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Sample records for infrared reflection spectroscopy

  1. Forensic applications of microscopical infrared internal reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Tungol, Mary W.; Bartick, Edward G.; Reffner, John A.

    1994-01-01

    Applications of microscopical infrared internal reflection spectroscopy in forensic science are discussed. Internal reflection spectra of single fibers, hairs, paint chips, vehicle rubber bumpers, photocopy toners, carbon copies, writing ink on paper, lipstick on tissue, black electrical tape, and other types of forensic evidence have been obtained. The technique is convenient, non-destructive, and may permit smeared materials to be analyzed in situ.

  2. [Identification of pearl powder using microscopic infrared reflectance spectroscopy].

    PubMed

    Zhang, Xuan; Hu, Chao; Yan, Yan; Yang, Hai-Feng; Li, Jun-Fang; Bai, Hua; Xi, Guang-Cheng; Liao, Jie

    2014-09-01

    Pearl is a precious ornament and traditional Chinese medicine, which application history in China is more than 2000 years. It is well known that the chemical ingredients of shell and pearl are very similar, which all of them including calcium carbonate and various amino acids. Generally, shell powders also can be used as medicine; however, its medicinal value is much lower than that of pearl powders. Due to the feature similarity between pearl powders and shell powders, the distinguishment of them by detecting chemical composition and morphology is very difficult. It should be noted that shell powders have been often posing as pearl powders in markets, which seriously infringes the interests of consumers. Identification of pearl powder was investigated by microscopic infrared reflectance spectroscopy, and pearl powder as well as shell powder was calcined at different temperatures for different time before infrared reflectance spectroscopy analysis. The experimental results indicated that when calcined at 400 °C for 30 minutes under atmospheric pressure, aragonite in pearl powder partly transformed into calcite, while aragonite in shell powder completely transformed into calcite. At the same time, the difference in phase transition between the pearl powders 'and shell powders can be easily detected by using the microscopic infrared reflectance spectroscopy. Therefore, based on the difference in their phase transition process, infrared reflectance spectroscopy can be used to identify phase transformation differences between pearl powder and shell powder. It's more meaningfully that the proposed infrared reflectance spec- troscopy method was also investigated for the applicability to other common counterfeits, such as oyster shell powders and abalone shell powders, and the results show that the method can be a simple, efficiently and accurately method for identification of pearl powder. PMID:25532338

  3. Analysis of silage composition by near-infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Reeves, James B., III; Blosser, Timothy H.; Colenbrander, V. F.

    1991-02-01

    Two studies were performed to investigate the feasibility of using near infrared reflectance spectroscopy (NIRS) with undried silages. In the first study silages were analyzed for major components (e. g. dry matter crude protein and other forms of nitrogen fiber and in vitro digestible dry matter) and short chain fatty acids (SCFA). NIRS was found to operate satisfactorily except for some forms of nitrogen and SCFA. In study two various methods of grinding spectral regions and sample presentation were examined. Undried Wiley ground samples in a rectangular cell gave the best overall results for non-dry ice undried grinds with wavelengths between 1100 and 2498 nm. Silages scanned after drying however produced the best results. Intact samples did not perform as well as ground samples and wavelengths below 1100 nm were of little use. 2 .

  4. Aerosol collection and analysis using diffuse reflectance infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Samuels, Alan C.; Wong, Diane M.; Meyer, Gerald J.; Roelant, Geoffrey J.; Williams, Barry R.; Miles, Ronald W., Jr.; Manning, Christopher J.

    2004-08-01

    Infrared spectroscopy is routinely employed for the identification of organic molecules and, more recently, for the classification of biological materials. We have developed a sample collection method that facilitates infrared analysis of airborne particulates using a diffuse reflectance (DR) technique. Efforts are underway to extend the method to include simultaneous analysis of vapor phase organics by using adsorbent substrates compatible with the DR technique. This series of laboratory results provides proof-of-principle for both the sample collection and data collection processes. Signal processing of the DR spectra is shown to provide rapid qualitative identification of representative aerosol materials, including particulate matter commonly found in the environment. We compare the results for such materials as bacterial spores, pollens and molds, clays and dusts, smoke and soot. Background correction analysis is shown to be useful for differentiation and identification of these constituents. Issues relating to complex mixtures of environmental samples under highly variable conditions are considered. Instrumentation development and materials research are now underway with the aim of constructing a compact sampling system for near real-time monitoring of aerosol and organic pollutants. A miniature, tilt-compensated Fourier transform spectrometer will provide spectroscopic interrogation. A series of advanced digital signal processing methods are also under development to enhance the sensor package. The approach will be useful for industrial applications, chemical and biological agent detection, and environmental monitoring for chemical vapors, hazardous air pollutants, and allergens.

  5. Determination of plant silicon content with near infrared reflectance spectroscopy

    PubMed Central

    Smis, Adriaan; Ancin Murguzur, Francisco Javier; Struyf, Eric; Soininen, Eeva M.; Herranz Jusdado, Juan G.; Meire, Patrick; Bråthen, Kari Anne

    2014-01-01

    Silicon (Si) is one of the most common elements in the earth bedrock, and its continental cycle is strongly biologically controlled. Yet, research on the biogeochemical cycle of Si in ecosystems is hampered by the time and cost associated with the currently used chemical analysis methods. Here, we assessed the suitability of Near Infrared Reflectance Spectroscopy (NIRS) for measuring Si content in plant tissues. NIR spectra depend on the characteristics of the present bonds between H and N, C and O, which can be calibrated against concentrations of various compounds. Because Si in plants always occurs as hydrated condensates of orthosilicic acid (Si(OH)4), linked to organic biomolecules, we hypothesized that NIRS is suitable for measuring Si content in plants across a range of plant species. We based our testing on 442 samples of 29 plant species belonging to a range of growth forms. We calibrated the NIRS method against a well-established plant Si analysis method by using partial least-squares regression. Si concentrations ranged from detection limit (0.24 ppmSi) to 7.8% Si on dry weight and were well predicted by NIRS. The model fit with validation data was good across all plant species (n = 141, R2 = 0.90, RMSEP = 0.24), but improved when only graminoids were modeled (n = 66, R2 = 0.95, RMSEP = 0.10). A species specific model for the grass Deschampsia cespitosa showed even slightly better results than the model for all graminoids (n = 16, R2 = 0.93, RMSEP = 0.015). We show for the first time that NIRS is applicable for determining plant Si concentration across a range of plant species and growth forms, and represents a time- and cost-effective alternative to the chemical Si analysis methods. As NIRS can be applied concurrently to a range of plant organic constituents, it opens up unprecedented research possibilities for studying interrelations between Si and other plant compounds in vegetation, and for addressing the role of Si in ecosystems across a range of Si

  6. [Application of near infrared reflectance spectroscopy to predict meat chemical compositions: a review].

    PubMed

    Tao, Lin-Li; Yang, Xiu-Juan; Deng, Jun-Ming; Zhang, Xi

    2013-11-01

    In contrast to conventional methods for the determination of meat chemical composition, near infrared reflectance spectroscopy enables rapid, simple, secure and simultaneous assessment of numerous meat properties. The present review focuses on the use of near infrared reflectance spectroscopy to predict meat chemical compositions. The potential of near infrared reflectance spectroscopy to predict crude protein, intramuscular fat, fatty acid, moisture, ash, myoglobin and collagen of beef, pork, chicken and lamb is reviewed. This paper discusses existing questions and reasons in the current research. According to the published results, although published results vary considerably, they suggest that near-infrared reflectance spectroscopy shows a great potential to replace the expensive and time-consuming chemical analysis of meat composition. In particular, under commercial conditions where simultaneous measurements of different chemical components are required, near infrared reflectance spectroscopy is expected to be the method of choice. The majority of studies selected feature-related wavelengths using principal components regression, developed the calibration model using partial least squares and modified partial least squares, and estimated the prediction accuracy by means of cross-validation using the same sample set previously used for the calibration. Meat fatty acid composition predicted by near-infrared spectroscopy and non-destructive prediction and visualization of chemical composition in meat using near-infrared hyperspectral imaging and multivariate regression are the hot studying field now. On the other hand, near infrared reflectance spectroscopy shows great difference for predicting different attributes of meat quality which are closely related to the selection of calibration sample set, preprocessing of near-infrared spectroscopy and modeling approach. Sample preparation also has an important effect on the reliability of NIR prediction; in particular

  7. Thermal infrared reflectance and emission spectroscopy of quartzofeldspathic glasses

    USGS Publications Warehouse

    Byrnes, J.M.; Ramsey, M.S.; King, P.L.; Lee, R.J.

    2007-01-01

    This investigation seeks to better understand the thermal infrared (TIR) spectral characteristics of naturally-occurring amorphous materials through laboratory synthesis and analysis of glasses. Because spectra of glass phases differ markedly from their mineral counterparts, examination of glasses is important to accurately determine the composition of amorphous surface materials using remote sensing datasets. Quantitatively characterizing TIR (5-25 ??m) spectral changes that accompany structural changes between glasses and mineral crystals provides the means to understand natural glasses on Earth and Mars. A suite of glasses with compositions analogous to common terrestrial volcanic glasses was created and analyzed using TIR reflectance and emission techniques. Documented spectral characteristics provide a basis for comparison with TIR spectra of other amorphous materials (glasses, clays, etc.). Our results provide the means to better detect and characterize glasses associated with terrestrial volcanoes, as well as contribute toward understanding the nature of amorphous silicates detected on Mars. Copyright 2007 by the American Geophysical Union.

  8. Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wehling, Randy L.

    Infrared (IR) spectroscopy refers to measurement of the absorption of different frequencies of IR radiation by foods or other solids, liquids, or gases. IR spectroscopy began in 1800 with an experiment by Herschel. When he used a prism to create a spectrum from white light and placed a thermometer at a point just beyond the red region of the spectrum, he noted an increase in temperature. This was the first observation of the effects of IR radiation. By the 1940s, IR spectroscopy had become an important tool used by chemists to identify functional groups in organic compounds. In the 1970s, commercial near-IR reflectance instruments were introduced that provided rapid quantitative determinations of moisture, protein, and fat in cereal grains and other foods. Today, IR spectroscopy is used widely in the food industry for both qualitative and quantitative analysis of ingredients and finished foods.

  9. [Application of near-infrared diffuse reflectance spectroscopy to the detection and identification of transgenic corn].

    PubMed

    Rui, Yu-kui; Luo, Yun-bo; Huang, Kun-lun; Wang, Wei-min; Zhang, Lu-da

    2005-10-01

    With the rapid development of the GMO, more and more GMO food has been pouring into the market. Much attention has been paid to GMO labeling under the controversy of GMO safety. Transgenic corns and their parents were scanned by continuous wave of near infrared diffuse reflectance spectroscopy range of 12000-4000 cm(-1); the resolution was 4 cm(-1); scanning was carried out for 64 times; BP algorithm was applied for data processing. The GMO food was easily resolved. Near-infrared diffuse reflectance spectroscopy is unpolluted and inexpensive compared with PCR and ELISA, so it is a very promising detection method for GMO food.

  10. [The research progress in determining lignocellulosic content by near infrared reflectance spectroscopy technology].

    PubMed

    Du, Juan; An, Dong; Xia, Tian; Huang, Yan-Hua; Li, Hong-Chao; Zhang, Yun-Wei

    2013-12-01

    Near infrared reflectance spectroscopy technology, as a new analytic method, can be used to determine the content of lignin, cellulose and hemi-cellulose which is faster, effective, easier to operate, and more accurate than the traditional wet chemical methods. Nowadays it has been widely used in measuring the composition of lignocelluloses in woody plant and herbaceous plant. The domestic and foreign research progress in determining the lignin, cellulose and hemi-cellulose content in woody plant ( wood and bamboo used as papermaking raw materials and wood served as potential biomass energy) and herbaceous plant (forage grass and energy grass) by near infrared reflectance spectroscopy technology is comprehensively summarized and the advances in method studies of measuring the composition of lignocelluloses by near infrared reflectance spectroscopy technology are summed up in three aspects, sample preparation, spectral data pretreatment and wavelength selection methods, and chemometric analysis respectively. Four outlooks are proposed combining the development statues of wood, forage grass and energy grass industry. First of all, the authors need to establish more feasible and applicable models for a variety of uses which can be used for more species from different areas, periods and anatomical parts. Secondly, comprehensive near infrared reflectance spectroscopy data base of grass products quality index needs to be improved to realize on-line quality and process control in grassproducts industry, which can guarantee the quality of the grass product. Thirdly, the near infrared reflectance spectroscopy quality index model of energy plant need to be built which can not only contribute to breed screening, but also improve the development of biomass industry. Besides, modeling approaches are required to be explored and perfected any further. Finally, the authors need to try our best to boost the advancement in the determination method of lignin, cellulose and hemi

  11. Tethered bilayer lipid membranes studied by simultaneous attenuated total reflectance infrared spectroscopy and electrochemical impedance spectroscopy

    PubMed Central

    Erbe, Andreas; Bushby, Richard J.; Evans, Stephen D.; Jeuken, Lars J. C.

    2013-01-01

    The formation of tethered lipid bilayer membranes (tBLMs) from unilamelar vesicles of egg yolk phosphatidylcholine (EggPC) on mixed self–assembled monolayers (SAMs) from varying ratios of 6-mercaptohexanol and EO3Cholesteryl on gold has been monitored by simultaneous attenuated total reflectance fourier transform infrared (ATR–FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS). The influence of the lipid orientation (and hence the anisotropy) of lipids on a gold film on the dichroic ratio was studied by simulations of spectra with a matrix method for anisotropic layers. It is shown that for certain tilt angles of the dielectric tensor of the adsorbed anisotropic layer dispersive and negative absorption bands are possible. The experimental data indicates that the structure of the assemblies obtained varies with varying SAM composition. On SAMs with a high content of EO3Cholesteryl, tBLMs with reduced fluidity are formed. For SAMs with high content of 6-mercaptohexanol, the results are consistent with the adsorption of flattened vesicles, while spherical vesicles have been found in a small range of surface compositions. The kinetics of the adsorption process is consistent with the assumption of spherical vesicles as long–living intermediates for surfaces of high 6-mercaptohexanol content. No long–living spherical vesicles have been detected for surfaces with large fraction of EO3Cholesteryl tethers. The observed differences between the surfaces suggest that for the formation of tBLMs (unlike supported BLMs) no critical surface coverage of vesicles is needed prior to lipid bilayer formation. PMID:17388505

  12. Infrared reflection-absorption spectroscopy of hyperfine layers on surfaces of semiconductors and dielectrics

    NASA Astrophysics Data System (ADS)

    Gruzinov, S. N.; Tolstoy, V. P.

    1988-02-01

    Infrared reflection-absorption spectroscopy of film son surfaces of transparent or weakly absorbing semiconductor and dielectric substrates is analyzed theoretically, the purpose being to establish the conditions for maximum sensitivity of this method. The absorption factor, namely the relative change of the reflection coefficient upon formation of a film on the substrate surface, is selected as the sensitivity criterion. The analysis is based on exact relations, one for a homogeneous isotopic absorbing film between substrate and ambient medium with plane-parallel boundaries and one for a reflecting layer with the possibility of multiple reflections taken into account. Calculations have been programmed on a computer for up to 60 nm thick SiO2 films on various substrates and infrared radiation within the 8 to 11 gmm waveband. The results indicate that the dependence of the absorption factor on the radiation wavelength and on the film thickness is different with the radiation s-polarized than with the radiation p-polarized. Calculations have also yielded the dispersion of optical constants characterizing a SiO2 film. According to these results, infrared spectroscopy is most sensitive to films on substrates with a small refractive index and when done with p-polarized radiation incident at exactly or approximately the Brewster angle for a determination of their presence and their composition respectively, also when no multiple reflections occur.

  13. Evaluation of thermal stability of indinavir sulphate using diffuse reflectance infrared spectroscopy.

    PubMed

    Singh, Parul; Premkumar, L; Mehrotra, Ranjana; Kandpal, H C; Bakhshi, A K

    2008-06-01

    Indinavir sulphate is a potent and specific protease inhibitor of human immunodeficiency virus (HIV). It is used for the treatment of acquired immune deficiency syndrome (AIDS). At elevated temperature the drug which otherwise remains crystalline undergoes a phase transition to an amorphous phase to form degradation products. In the present study, thermal stability of indinavir sulphate is evaluated using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Infrared spectra of the drug before and after the exposure to thermal radiation at different temperatures were acquired in the diffuse reflectance mode using a Fourier transform infrared (FTIR) spectrophotometer. The differential scanning calorimetry (DSC) and the X-ray diffraction (XRD) studies were used as complimentary techniques to adequately implement and assist the interpretation of the infrared spectroscopy results. The DRIFT spectra reveal that the drug remains stable up to 100 degrees C, degrades slightly at 125 degrees C and undergoes complete degradation at about 150 degrees C to produce degradation products. The degradation products can easily be characterized using the infrared spectra.

  14. [Sugar characterization of mini-watermelon and rapid sugar determination by near infrared diffuse reflectance spectroscopy].

    PubMed

    Wang, Shuo; Yuan, Hong-fu; Song, Chun-feng; Xie, Jin-chun; Li, Xiao-yu; Feng, Le-ping

    2012-08-01

    In the present paper, the distribution of sugar level within the mini-watermelon was studied, a new sugar characterization method of mini-watermelon using average sugar level, the highest sugar level and the lowest sugar level index is proposed. Feasibility of nondestructive determination of mini-watermenlon sugar level using diffuse reflectance spectroscopy information was investigated by an experiment. PLS models for measuring the 3 sugar levels were established. The results obtained by near infrared spectroscopy agreed with that of the new method established above.

  15. Characterization of Material Degradation in Ceramic Matrix Composites Using Infrared Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cooney, Adam T.; Flattum-Riemers, Richard Y.; Scott, Benjamin J.

    2011-06-01

    Ceramic matrix composite materials for thermal protection systems are required to maintain operational performance in extreme thermal and mechanical environments. In-service inspection of materials capable of assessing the degree and extent of damage and degradation will be required to ensure the safety and readiness of future air vehicles. Infrared reflectance spectroscopy is an established material characterization technique capable of extracting information regarding the chemical composition of substances. The viability of this technique as a potentially powerful nondestructive evaluation method capable of monitoring degradation in thermal protection system materials subjected to extreme mechanical and thermal environments is analyzed. Several oxide-based and non-oxide-based ceramic matrix composite materials were stressed to failure in a high temperature environment and subsequently measured using infrared reflectance spectroscopy. Spectral signatures at locations along the length of the samples were compared resulting in distinct and monotonic reflectance peak changes while approaching the fracture point. The chemical significance of the observed signatures and the feasibility of infrared reflectance nondestructive evaluation techniques are discussed.

  16. Rheo-attenuated total reflectance infrared spectroscopy: a new tool to study biopolymers.

    PubMed

    Boulet-Audet, Maxime; Vollrath, Fritz; Holland, Chris

    2011-03-01

    Whilst rheology is the reference technique to study the mechanical properties of unspun silk, we know little of the structure and the dynamics that generate them. By coupling infrared spectroscopy and shearing forces to study silk fibroin conversion, we are introducing a novel tool to address this gap in our knowledge. Here the silk conversion process has been studied dynamically using polarized attenuated total reflectance Fourier transform infrared spectroscopy whilst applying shear, thus revealing silk protein conformation and molecular orientation in situ. Our results show that the silk conversion process starts with a pre-alignment of the proteins followed by a rapid growth of the β-sheet formation and then a subsequent deceleration of the growth. We propose that this tool will provide further insight into not only silk but any biopolymer solution, opening a new window into biological materials.

  17. Infrared Attenuated Total Reflectance Spectroscopy: An Innovative Strategy for Analyzing Mineral Components in Energy Relevant Systems

    PubMed Central

    Müller, Christian Menno; Pejcic, Bobby; Esteban, Lionel; Piane, Claudio Delle; Raven, Mark; Mizaikoff, Boris

    2014-01-01

    The direct qualitative and quantitative determination of mineral components in shale rocks is a problem that has not been satisfactorily resolved to date. Infrared spectroscopy (IR) is a non-destructive method frequently used in mineral identification, yet challenging due to the similarity of spectral features resulting from quartz, clay, and feldspar minerals. This study reports on a significant improvement of this methodology by combining infrared attenuated total reflection spectroscopy (IR-ATR) with partial least squares (PLS) regression techniques for classifying and quantifying various mineral components present in a number of different shale rocks. The developed multivariate classification model was calibrated using pure component mixtures of the most common shale minerals (i.e., kaolinite, illite, montmorillonite, calcite, and quartz). Using this model, the IR spectra of 11 real-world shale samples were analyzed and evaluated. Finally, the performance of the developed IR-ATR method was compared with results obtained via X-ray diffraction (XRD) analysis. PMID:25358261

  18. Multipitched Diffraction Gratings for Surface Plasmon Resonance-Enhanced Infrared Reflection Absorption Spectroscopy.

    PubMed

    Petefish, Joseph W; Hillier, Andrew C

    2015-11-01

    We demonstrate the application of metal-coated diffraction gratings possessing multiple simultaneous pitch values for surface enhanced infrared absorption (SEIRA) spectroscopy. SEIRA increases the magnitude of vibrational signals in infrared measurements by one of several mechanisms, most frequently involving the enhanced electric field associated with surface plasmon resonance (SPR). While the majority of SEIRA applications to date have employed nanoparticle-based plasmonic systems, recent advances have shown how various metals and structures lead to similar signal enhancement. Recently, diffraction grating couplers have been demonstrated as a highly tunable platform for SEIRA. Indeed, gratings are an experimentally advantageous platform due to the inherently tunable nature of surface plasmon excitation at these surfaces since both the grating pitch and incident angle can be used to modify the spectral location of the plasmon resonance. In this work, we use laser interference lithography (LIL) to fabricate gratings possessing multiple pitch values by subjecting photoresist-coated glass slides to repetitive exposures at varying orientations. After metal coating, these gratings produced multiple, simultaneous plasmon peaks associated with the multipitched surface, as identified by infrared reflectance measurements. These plasmon peaks could then be coupled to vibrational modes in thin films to provide localized enhancement of infrared signals. We demonstrate the flexibility and tunability of this platform for signal enhancement. It is anticipated that, with further refinement, this approach might be used as a general platform for broadband enhancement of infrared spectroscopy. PMID:26458177

  19. Multipitched Diffraction Gratings for Surface Plasmon Resonance-Enhanced Infrared Reflection Absorption Spectroscopy.

    PubMed

    Petefish, Joseph W; Hillier, Andrew C

    2015-11-01

    We demonstrate the application of metal-coated diffraction gratings possessing multiple simultaneous pitch values for surface enhanced infrared absorption (SEIRA) spectroscopy. SEIRA increases the magnitude of vibrational signals in infrared measurements by one of several mechanisms, most frequently involving the enhanced electric field associated with surface plasmon resonance (SPR). While the majority of SEIRA applications to date have employed nanoparticle-based plasmonic systems, recent advances have shown how various metals and structures lead to similar signal enhancement. Recently, diffraction grating couplers have been demonstrated as a highly tunable platform for SEIRA. Indeed, gratings are an experimentally advantageous platform due to the inherently tunable nature of surface plasmon excitation at these surfaces since both the grating pitch and incident angle can be used to modify the spectral location of the plasmon resonance. In this work, we use laser interference lithography (LIL) to fabricate gratings possessing multiple pitch values by subjecting photoresist-coated glass slides to repetitive exposures at varying orientations. After metal coating, these gratings produced multiple, simultaneous plasmon peaks associated with the multipitched surface, as identified by infrared reflectance measurements. These plasmon peaks could then be coupled to vibrational modes in thin films to provide localized enhancement of infrared signals. We demonstrate the flexibility and tunability of this platform for signal enhancement. It is anticipated that, with further refinement, this approach might be used as a general platform for broadband enhancement of infrared spectroscopy.

  20. [Detection of erucic acid and glucosinolate in intact rapeseed by near-infrared diffuse reflectance spectroscopy].

    PubMed

    Riu, Yu-kui; Huang, Kun-lun; Wang, Wei-min; Guo, Jing; Jin, Yin-hua; Luo, Yun-bo

    2006-12-01

    With the rapid development of transgenic food, more and more transgenic food has been pouring into the market, raising great concern about transgenic food' s edible safety. To analyze the content of erucic acid and glucosinolate in transgenic rapeseed and its parents, all the seeds were scanned intact by continuous wave of near infrared diffuse reflectance spectrometry ranging from 12 000 to 4 000 cm(-1) with a resolution of 4 cm(-1) and 64 times of scanning. Bruker OPUS software package was applied for quantification, while the results were compared with the standard methods. The results showed that the method of NIRS was very precise, which proved that infrared diffuse reflectance spectroscopy can be applied to detect the toxins in transgenic food. On the other hand, the results also showed that the content of erucic acid in transgenic rapeseeds is 0. 5-1. 0 times

  1. Modelling of sensory and instrumental texture parameters in processed cheese by near infrared reflectance spectroscopy.

    PubMed

    Blazquez, Carmen; Downey, Gerard; O'Callaghan, Donal; Howard, Vincent; Delahunty, Conor; Sheehan, Elizabeth; Everard, Colm; O'Donnell, Colm P

    2006-02-01

    This study investigated the application of near infrared (NIR) reflectance spectroscopy to the measurement of texture (sensory and instrumental) in experimental processed cheese samples. Spectra (750 to 2498 nm) of cheeses were recorded after 2 and 4 weeks storage at 4 degrees C. Trained assessors evaluated 9 sensory properties, a texture profile analyser (TPA) was used to record 5 instrumental parameters and cheese 'meltability' was measured by computer vision. Predictive models for sensory and instrumental texture parameters were developed using partial least squares regression on raw or pre-treated spectral data. Sensory attributes and instrumental texture measurements were modelled with sufficient accuracy to recommend the use of NIR reflectance spectroscopy for routine quality assessment of processed cheese. PMID:16433962

  2. Titanium-silicon oxide film structures for polarization-modulated infrared reflection absorption spectroscopy

    PubMed Central

    Dunlop, Iain E.; Zorn, Stefan; Richter, Gunther; Srot, Vesna; Kelsch, Marion; van Aken, Peter A.; Skoda, Maximilian; Gerlach, Alexander; Spatz, Joachim P.; Schreiber, Frank

    2010-01-01

    We present a titanium-silicon oxide film structure that permits polarization modulated infrared reflection absorption spectroscopy on silicon oxide surfaces. The structure consists of a ~6 nm sputtered silicon oxide film on a ~200 nm sputtered titanium film. Characterization using conventional and scanning transmission electron microscopy, electron energy loss spectroscopy, X-ray photoelectron spectroscopy and X-ray reflectometry is presented. We demonstrate the use of this structure to investigate a selectively protein-resistant self-assembled monolayer (SAM) consisting of silane-anchored, biotin-terminated poly(ethylene glycol) (PEG). PEG-associated IR bands were observed. Measurements of protein-characteristic band intensities showed that this SAM adsorbed streptavidin whereas it repelled bovine serum albumin, as had been expected from its structure. PMID:20418963

  3. [Rapid determination of fatty acids in soybean oils by transmission reflection-near infrared spectroscopy].

    PubMed

    Song, Tao; Zhang, Feng-ping; Liu, Yao-min; Wu, Zong-wen; Suo, You-rui

    2012-08-01

    In the present research, a novel method was established for determination of five fatty acids in soybean oil by transmission reflection-near infrared spectroscopy. The optimum conditions of mathematics model of five components (C16:0, C18:0, C18:1, C18:2 and C18:3) were studied, including the sample set selection, chemical value analysis, the detection methods and condition. Chemical value was analyzed by gas chromatography. One hundred fifty eight samples were selected, 138 for modeling set, 10 for testing set and 10 for unknown sample set. All samples were placed in sample pools and scanned by transmission reflection-near infrared spectrum after sonicleaning for 10 minute. The 1100-2500 nm spectral region was analyzed. The acquisition interval was 2 nm. Modified partial least square method was chosen for calibration mode creating. Result demonstrated that the 1-VR of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.8839, 0.5830, 0.9001, 0.9776 and 0.9596, respectively. And the SECV of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.42, 0.29, 0.83, 0.46 and 0.21, respectively. The standard error of the calibration (SECV) of five fatty acids between the reference value of testing sample set and the near infrared spectrum predictive value were 0.891, 0.790, 0.900, 0.976 and 0.942, respectively. It was proved that the near infrared spectrum predictive value was linear with chemical value and the mathematical model established for fatty acids of soybean oil was feasible. For validation, 10 unknown samples were selected for analysis by near infrared spectrum. The result demonstrated that the relative standard deviation between predict value and chemical value was less than 5.50%. That was to say that transmission reflection-near infrared spectroscopy had a good veracity in analysis of fatty acids of soybean oil.

  4. Infrared reflectance spectroscopy as a characterization probe for polymer surfaces and interfaces

    NASA Astrophysics Data System (ADS)

    Riou, Sophie Annick

    1998-12-01

    Only recently has external reflectance infrared spectroscopy been used to acquire structural information at the molecular level at air-liquid interfaces, and particularly to characterize in situ molecular chains adsorbed at the air-water interface. This technique has been applied for the determination of chain orientation, chain conformation and packing density of small molecules such as phospholipids, fatty acids and fatty alcohols on the surface of water, and more recently of macromolecular systems. Vibrational spectroscopy, a nondestructive technique, is especially successful in the determination of the conformational order or disorder of alkyl chains (e.g. trans/gauche ratio) as well as in the evaluation of coil, helical or extended conformations in poly(amino acids). In this thesis work, the construction of a microcomputer controlled Langmuir trough optically coupled to a FT-IR instrument has allowed the direct investigation of molecular films spread at air-liquid interfaces. Order-disorder transitions and relaxation behaviors in vinyl comb-like polymeric Langmuir films have been examined using simultaneously external reflection infrared spectroscopy and surface tensiometry. The structures of several poly(amino acid) films have also been studied as a function of surface packing density at the air-water interface.

  5. Preliminary Method for Direct Quantification of Colistin Methanesulfonate by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

    PubMed Central

    Niece, Krista L.

    2015-01-01

    Colistin use has increased in response to the advent of infections caused by multidrug-resistant organisms. It is administered parenterally as an inactive prodrug, colistin methanesulfonate (CMS). Various formulations of CMS and labeling conventions can lead to confusion about colistin dosing, and questions remain about the pharmacokinetics of CMS. Since CMS does not have strong UV absorbance, current methods employ a laborious process of chemical conversion to colistin followed by precolumn derivatization to detect formed colistin by high-performance liquid chromatography. Here, we report a method for direct quantification of colistin methanesulfonate by attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR). PMID:26124160

  6. Preliminary method for direct quantification of colistin methanesulfonate by attenuated total reflectance Fourier transform infrared spectroscopy.

    PubMed

    Niece, Krista L; Akers, Kevin S

    2015-09-01

    Colistin use has increased in response to the advent of infections caused by multidrug-resistant organisms. It is administered parenterally as an inactive prodrug, colistin methanesulfonate (CMS). Various formulations of CMS and labeling conventions can lead to confusion about colistin dosing, and questions remain about the pharmacokinetics of CMS. Since CMS does not have strong UV absorbance, current methods employ a laborious process of chemical conversion to colistin followed by precolumn derivatization to detect formed colistin by high-performance liquid chromatography. Here, we report a method for direct quantification of colistin methanesulfonate by attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR).

  7. [Applications of near infrared reflectance spectroscopy technique (NIRS) to soil attributes research].

    PubMed

    Liu, Yan-De; Xiong, Song-Sheng; Liu, De-Li

    2014-10-01

    Soil is a much complicated substance, because animals, plants and microbes live together, organic and inorganic exist together. So soil contains a large amount of information. The traditional method in laboratory is a time-consuming effort. But the technology of near infrared reflectance spectroscopy (NIRS) has been widely used in many areas, owing to its rapidness, high efficiency, no pollution and low cost, NIRS has become the most important method to detect the composition of soil. This paper mainly introduce some traditional methods in laboratory, the basic processes of soil detection by NIRS, some algorithms for data preprocessing and modeling. Besides, the present paper illustrates the latest research progress and the development of portable near infrared instruments of the soil. According to this paper, the authors also hope to promote the application conditions of NIRS in the grassland ecology research in China, and accelerate the modernization of research measures in this area.

  8. Determination of in vivo skin moisture level by near-infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Saknite, Inga; Spigulis, Janis

    2015-03-01

    Near-infrared spectroscopy has a potential for noninvasive determination of skin moisture level due to high water absorption. In this study, diffuse reflectance spectra of in vivo skin were acquired in the spectral range of 900 nm to 1700 nm by using near-infrared spectrometer, optical fiber and halogen bulb light source. Absorption changes after applying skin moisturizers were analyzed over time at different body sites. Results show difference in absorption when comparing dry and normal skin. Comparison of absorption changes over time after applying moisturizer at different body sites is analyzed and discussed. Some patterns of how skin reacts to different skin moisturizers are shown, although no clear pattern can be seen due to signal noise.

  9. Noninvasive blood glucose sensing on human body with near-infrared reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Zhen-hao; Hao, Chang-ning; Zhang, Lin-lin; Huang, Yan-chao; Shi, Yi-qin; Jiang, Geng-ru; Duan, Jun-li

    2011-08-01

    The non-invasive blood glucose sensing method has shown its high impact on the clinic application. This can make the measurement on the clinically relevant concentrations of glucose be free from the pain of patient. The transmission spectrum study indicates that the dependence of glucose concentration on the absorbance is in linear manner for the glucose concentration in the region of 30mg/dL to 4.5×104mg/dL. By the near infrared reflection spectroscopy of fiber spectrometer, the reflection band between 1.2μm and 1.35μm can be used to correlated with the glucose concentration in the range of 30 to 300 mg/dL. This reflection band is finally used to measure the glucose concentration effect in non-invasive manner, which gives the statistical significance of P value 0.02. Our experiment result shows that it is possible to get the glucose concentration by the near infrared reflection spectrum measurement on the human forefinger. This non-invasive blood glucose sensing method may useful in clinic after more experiment for different people.

  10. Sediment mineralogy based on visible and near-infrared reflectance spectroscopy

    USGS Publications Warehouse

    Jarrard, R.D.; Vanden Berg, M.D.; ,

    2006-01-01

    Visible and near-infrared spectroscopy (VNIS) can be used to measure reflectance spectra (wavelength 350-2500 nm) for sediment cores and samples. A local ground-truth calibration of spectral features to mineral percentages is calculated by measuring reflectance spectra for a suite of samples of known mineralogy. This approach has been tested on powders, core plugs and split cores, and we conclude that it works well on all three, unless pore water is present. Initial VNIS studies have concentrated on determination of relative proportions of carbonate, opal, smectite and illite in equatorial Pacific sediments. Shipboard VNIS-based determination of these four components was demonstrated on Ocean Drilling Program Leg 199. ?? The Geological Society of London 2006.

  11. Classification of the waxy condition of durum wheat by near infrared reflectance spectroscopy using wavelets and a genetic algorithm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infrared (NIR) reflectance spectroscopy has been applied to the problem of differentiating four genotypes of durum wheat: ‘waxy’, wx-A1 null, wx-B1 null and wild type. The test data consisted of 95 NIR reflectance spectra of wheat samples obtained from a USDA-ARS wheat breeding program. A two...

  12. Attenuated total reflectance Fourier-transform infrared spectroscopy of carboxylic acids adsorbed onto mineral surfaces

    NASA Astrophysics Data System (ADS)

    Kubicki, J. D.; Schroeter, L. M.; Itoh, M. J.; Nguyen, B. N.; Apitz, S. E.

    1999-09-01

    A suite of naturally-occurring carboxylic acids (acetic, oxalic, citric, benzoic, salicylic and phthalic) and their corresponding sodium salts were adsorbed onto a set of common mineral substrates (quartz, albite, illite, kaolinite and montmorillonite) in batch slurry experiments. Solution pH's of approximately 3 and 6 were used to examine the effects of pH on sorption mechanisms. Attenuated total reflectance Fourier-transform infrared (ATR FTIR) spectroscopy was employed to obtain vibrational frequencies of the organic ligands on the mineral surfaces and in solution. UV/visible spectroscopy on supernatant solutions was also employed to confirm that adsorption from solution had taken place for benzoic, salicylic and phthalic acids. Molecular orbital calculations were used to model possible surface complexes and interpret the experimental spectra. In general, the tectosilicates, quartz and albite feldspar, did not chemisorb (i.e., strong, inner-sphere adsorption) the carboxylate anions in sufficient amounts to produce infrared spectra of the organics after rinsing in distilled water. The clays (illite, kaolinite and montmorillonite) each exhibited similar ATR FTIR spectra. However, the illite sample used in this study reacted to form strong surface and aqueous complexes with salicylic acid before being treated to remove free Fe-hydroxides. Chemisorption of carboxylic acids onto clays is shown to be limited without the presence of Fe-hydroxides within the clay matrix.

  13. Catheter based mid-infrared reflectance and reflectance generated absorption spectroscopy

    SciTech Connect

    Holman, Hoi-Ying N

    2013-10-29

    A method of characterizing conditions in a tissue, by (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-IR spectrum; (b) directing the light from the catheter to an area of tissue at a location inside a blood vessel of a subject; (c) collecting light reflected from the location and generating a reflectance spectra; and (d) comparing the reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a tissue inside the blood vessel containing a physiological marker for atherosclerosis.

  14. Mineralogical and spectroscopic investigation of enstatite chondrites by X-ray diffraction and infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Izawa, M. R.; King, P. L.; Flemming, R. L.; Peterson, R. C.; McCausland, P. J.

    2009-05-01

    Reflectance spectroscopy of well-characterized meteorites provides an important means of linking meteorites to potential parent objects; an important objective in meteoritics research. There is a lack of such sample- correlated spectroscopic and mineralogical data sets in the literature to date. In an effort to improve this situation, the bulk mineralogy and infrared reflectance spectra of 13 enstatite chondrite meteorite finds, spanning the full range of textural alteration grades in both EL and EH classes have been investigated, including eleven recovered from the Antarctic and one from Northwest Africa. Rietveld refinement of high- resolution powder X-ray diffraction (XRD) data was used to identify the major mineral phases and quantify their modal abundances. The mineralogy and modes agree well with those of well-documented enstatite chondrites. Terrestrial weathering products such as Fe-oxyhydroxides, gypsum, and carbonates also occur in most of the meteorites from Antarctica. The mineral abundances determined via Rietveld refinement have been used to calculate model grain densities for each meteorite (i.e. density of the solid phases). Bulk magnetic susceptibility measurements combined with modal mineralogy reveal that as terrestrial weathering increases, both grain density and bulk susceptibility decrease. Sample-correlated thermal infrared (400-4500 cm-1, 2-25 μm) biconical (Diffuse) Reflectance Infrared Fourier Transform Spectroscopy data were collected for each meteorite to facilitate comparison with remote sensing data. The meteorite spectra are dominated by features corresponding to enstatite. Terrestrial weathering manifests itself as a broad, asymmetric H2O band centered near ~3400 cm-1, analogous to the "3 μm water of hydration feature" recognized in asteroid spectra, particularly from the enigmatic W-type asteroids. Additional sharp features superimposed on this band, as well as the sharpness of an asymmetric feature related to bound molecular

  15. Infrared reflection-absorption spectroscopy: principles and applications to lipid-protein interaction in Langmuir films.

    PubMed

    Mendelsohn, Richard; Mao, Guangru; Flach, Carol R

    2010-04-01

    Infrared reflection-absorption spectroscopy (IRRAS) of lipid/protein monolayer films in situ at the air/water interface provides unique molecular structure and orientation information from the film constituents. The technique is thus well suited for studies of lipid/protein interaction in a physiologically relevant environment. Initially, the nature of the IRRAS experiment is described and the molecular structure information that may be obtained is recapitulated. Subsequently, several types of applications, including the determination of lipid chain conformation and tilt as well as elucidation of protein secondary structure are reviewed. The current article attempts to provide the reader with an understanding of the current capabilities of IRRAS instrumentation and the type of results that have been achieved to date from IRRAS studies of lipids, proteins, and lipid/protein films of progressively increasing complexity. Finally, possible extensions of the technology are briefly considered. PMID:20004639

  16. Detection of whitening agents in illegal cosmetics using attenuated total reflectance-infrared spectroscopy.

    PubMed

    Deconinck, E; Bothy, J L; Desmedt, B; Courselle, P; De Beer, J O

    2014-09-01

    Cosmetic products containing illegal whitening agents are still found on the European market. They represent a considerable risk to public health, since they are often characterised by severe side effects when used chronically. The detection of such products at customs is not always simple, due to misleading packaging and the existence of products containing only legal components. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. The use of attenuated total reflectance-infrared (ATR-IR) spectroscopy, combined with chemometrics, was evaluated for that purpose. It was found that the combination of ATR-IR with the simple chemometric technique k-nearest neighbours gave good results. A model was obtained in which a minimum of illegal samples was categorised as legal. The correctly classified illegal samples could be attributed to the illegal components present.

  17. Detection of whitening agents in illegal cosmetics using attenuated total reflectance-infrared spectroscopy.

    PubMed

    Deconinck, E; Bothy, J L; Desmedt, B; Courselle, P; De Beer, J O

    2014-09-01

    Cosmetic products containing illegal whitening agents are still found on the European market. They represent a considerable risk to public health, since they are often characterised by severe side effects when used chronically. The detection of such products at customs is not always simple, due to misleading packaging and the existence of products containing only legal components. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. The use of attenuated total reflectance-infrared (ATR-IR) spectroscopy, combined with chemometrics, was evaluated for that purpose. It was found that the combination of ATR-IR with the simple chemometric technique k-nearest neighbours gave good results. A model was obtained in which a minimum of illegal samples was categorised as legal. The correctly classified illegal samples could be attributed to the illegal components present. PMID:24927403

  18. Estimation of blood alcohol concentration by horizontal attenuated total reflectance-Fourier transform infrared spectroscopy.

    PubMed

    Sharma, Kakali; Sharma, Shiba P; Lahiri, Sujit C

    2010-06-01

    Numerous methods like distillation followed by iodometric titrations, gas chromatograph (GC)-flame ionization detector, gas chromatograph-mass spectrophotometer, GC-Headspace, Breath analyzer, and biosensors including alcohol dehydrogenase (enzymatic) have been used to determine blood alcohol concentration (BAC). In the present study, horizontal attenuated total reflectance-Fourier transform infrared spectroscopy had been used to determine BAC in whole blood. The asymmetric stretching frequency of C-C-O group of ethanol in water (1,045 cm(-1)) had been used to calculate BAC using Beer's Law. A seven-point calibration curve of ethanol was drawn in the concentration range 24-790 mg dL(-1). The curve showed good linearity over the concentration range used (r(2)=0.999, standard deviation=0.0023). The method is accurate, reproducible, rapid, simple, and nondestructive in nature. PMID:20541351

  19. Fast determination of total ginsenosides content in ginseng powder by near infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Hua-cai; Chen, Xing-dan; Lu, Yong-jun; Cao, Zhi-qiang

    2006-01-01

    Near infrared (NIR) reflectance spectroscopy was used to develop a fast determination method for total ginsenosides in Ginseng (Panax Ginseng) powder. The spectra were analyzed with multiplicative signal correction (MSC) correlation method. The best correlative spectra region with the total ginsenosides content was 1660 nm~1880 nm and 2230nm~2380 nm. The NIR calibration models of ginsenosides were built with multiple linear regression (MLR), principle component regression (PCR) and partial least squares (PLS) regression respectively. The results showed that the calibration model built with PLS combined with MSC and the optimal spectrum region was the best one. The correlation coefficient and the root mean square error of correction validation (RMSEC) of the best calibration model were 0.98 and 0.15% respectively. The optimal spectrum region for calibration was 1204nm~2014nm. The result suggested that using NIR to rapidly determinate the total ginsenosides content in ginseng powder were feasible.

  20. Reflection-Absorption Infrared Spectroscopy of Thin Films Using an External Cavity Quantum Cascade Laser

    SciTech Connect

    Phillips, Mark C.; Craig, Ian M.; Blake, Thomas A.

    2013-02-04

    We present experimental demonstrations using a broadly tunable external cavity quantum cascade laser (ECQCL) to perform Reflection-Absorption InfraRed Spectroscopy (RAIRS) of thin layers and residues on surfaces. The ECQCL compliance voltage was used to measure fluctuations in the ECQCL output power and improve the performance of the RAIRS measurements. Absorption spectra from self-assembled monolayers of a fluorinated alkane thiol and a thiol carboxylic acid were measured and compared with FTIR measurements. RAIRS spectra of the explosive compounds PETN, RDX, and tetryl deposited on gold substrates were also measured. Rapid measurement times and low noise were demonstrated, with < 1E-3 absorbance noise for a 10 second measurement time.

  1. Depth profile characterization technique for electron density in GaN films by infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Kamijoh, Takaaki; Ma, Bei; Morita, Ken; Ishitani, Yoshihiro

    2016-05-01

    Infrared reflectance spectroscopy is a noncontact measurement method for carrier density and mobility. In this article, the model determination procedure of layer-type nonuniform electron distribution is investigated, since the spectrum fitting hitherto has been conducted on the basis of a multilayer model defined in advance. A simplified case of a high-electron-density GaN layer embedded in a GaN matrix is mainly studied. The following procedure is found to be applicable. The first step is the determination of the high-density layer position in the vicinity of the surface, in the middle region, or in the vicinity of the interface. This is followed by the specification of the sheet electron density and the layer thickness of the high-density region. It is found that this procedure is also applicable to the characterization of two-dimensional electron gases in the vicinity of AlGaN/GaN heterointerfaces.

  2. Understanding the collapse mechanism in Langmuir monolayers through polarization modulation-infrared reflection absorption spectroscopy.

    PubMed

    Goto, Thiago Eichi; Caseli, Luciano

    2013-07-23

    The collapse of films at the air-water interface is related to a type of 2D-to-3D transition that occurs when a Langmuir monolayer is compressed beyond its stability limit. Studies on this issue are extremely important because defects in ultrathin solid films can be better understood if the molecular mechanisms related to collapse processes are elucidated. This paper explores how the changes of vibration of specific groups of lipid molecules, as revealed by polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS), are affected by the monolayer collapse. Different mechanisms of collapse were studied, for those lipids that undergo constant-area collapse (such as stearic acid) and for those that undergo constant-pressure collapse (such as DPPC, DPPG, and DODAB). Lipid charges also affect the mechanism of collapse, as demonstrated for two oppositely charged lipids.

  3. [Testing of germination rate of hybrid rice seeds based on near-infrared reflectance spectroscopy].

    PubMed

    Li, Yi-nian; Jiang, Dan; Liu, Ying-ying; Ding, Wei-min; Ding, Qi-shuo; Zha, Liang-yu

    2014-06-01

    Germination rate of rice seeds was measured according to technical stipulation of germination testing for agricultural crop seeds at present. There existed many faults for this technical stipulation such as long experimental period, more costing and higher professional requirement. A rapid and non-invasive method was put forward to measure the germination rate of hybrid rice seeds based on near-infrared reflectance spectroscopy. Two varieties of hybrid rice seeds were aged artificially at temperature 45 degrees C and humidity 100% condition for 0, 24, 48, 72, 96, 120 and 144 h. Spectral data of 280 samples for 2 varieties of hybrid rice seeds with different aging time were acquired individually by near-infrared spectra analyzer. Spectral data of 280 samples for 2 varieties of hybrid rice seeds were randomly divided into calibration set (168 samples) and prediction set (112 samples). Gormination rate of rice seed with different aging time was tested. Regression model was established by using partial least squares (PLS). The effect of the different spectral bands on the accuracy of models was analyzed and the effect of the different spectral preprocessing methods on the accuracy of models was also compared. Optimal model was achieved under the whole bands and by using standardization and orthogonal signal correction (OSC) preprocessing algorithms with CM2000 software for spectral data of 2 varieties of hybrid rice seeds, the coefficient of determination of the calibration set (Rc) and that of the prediction set (Rp) were 0.965 and 0.931 individually, standard error of calibration set (SEC) and that of prediction set (SEP) were 1.929 and 2.899 respectively. Relative error between tested value and predicted value for prediction set of rice seeds is below 4.2%. The experimental results show that it is feasible that rice germination rate is detected rapidly and nondestructively by using the near-infrared spectroscopy analysis technology. PMID:25358159

  4. [Testing of germination rate of hybrid rice seeds based on near-infrared reflectance spectroscopy].

    PubMed

    Li, Yi-nian; Jiang, Dan; Liu, Ying-ying; Ding, Wei-min; Ding, Qi-shuo; Zha, Liang-yu

    2014-06-01

    Germination rate of rice seeds was measured according to technical stipulation of germination testing for agricultural crop seeds at present. There existed many faults for this technical stipulation such as long experimental period, more costing and higher professional requirement. A rapid and non-invasive method was put forward to measure the germination rate of hybrid rice seeds based on near-infrared reflectance spectroscopy. Two varieties of hybrid rice seeds were aged artificially at temperature 45 degrees C and humidity 100% condition for 0, 24, 48, 72, 96, 120 and 144 h. Spectral data of 280 samples for 2 varieties of hybrid rice seeds with different aging time were acquired individually by near-infrared spectra analyzer. Spectral data of 280 samples for 2 varieties of hybrid rice seeds were randomly divided into calibration set (168 samples) and prediction set (112 samples). Gormination rate of rice seed with different aging time was tested. Regression model was established by using partial least squares (PLS). The effect of the different spectral bands on the accuracy of models was analyzed and the effect of the different spectral preprocessing methods on the accuracy of models was also compared. Optimal model was achieved under the whole bands and by using standardization and orthogonal signal correction (OSC) preprocessing algorithms with CM2000 software for spectral data of 2 varieties of hybrid rice seeds, the coefficient of determination of the calibration set (Rc) and that of the prediction set (Rp) were 0.965 and 0.931 individually, standard error of calibration set (SEC) and that of prediction set (SEP) were 1.929 and 2.899 respectively. Relative error between tested value and predicted value for prediction set of rice seeds is below 4.2%. The experimental results show that it is feasible that rice germination rate is detected rapidly and nondestructively by using the near-infrared spectroscopy analysis technology.

  5. Identification of cattle, llama and horse meat by near infrared reflectance or transflectance spectroscopy.

    PubMed

    Mamani-Linares, L W; Gallo, C; Alomar, D

    2012-02-01

    Visible and near infrared reflectance spectroscopy (VIS-NIRS) was used to discriminate meat and meat juices from three livestock species. In a first trial, samples of Longissimus lumborum muscle, corresponding to beef (31) llamas (21) and horses (27), were homogenised and their spectra collected in reflectance (NIRSystems 6500 scanning monochromator, in the range of 400-2500 nm). In the second trial, samples of meat juice (same muscle) from the same species (20 beef, 19 llama and 19 horse) were scanned in folded transmission (transflectance). Discriminating models (PLS regression) were developed against "dummy" variables, testing different mathematical treatments of the spectra. Best models indentified the species of almost all samples by their meat (reflectance) or meat juice (transflectance) spectra. A few (three of beef and one of llama, for meat samples; one of beef and one of horse, for juice samples) were classified as uncertain. It is concluded that NIRS is an effective tool to recognise meat and meat juice from beef, llama and horses.

  6. Nondestructive inspection of organic films on sandblasted metals using diffuse reflectance infrared spectroscopy

    SciTech Connect

    Powell, G.L.; Cox, R.L.; Barber, T.E.; Neu, J.T.

    1996-07-08

    Diffuse reflectance infrared spectroscopy is a very useful tool for the determination of surface contamination and characterization of films in manufacturing applications. Spectral data from the surfaces of a host of practical materials may be obtained with sufficient insensitivity to characterize relatively thick films, such as paint, and the potential exists to detect very thin films, such as trace oil contamination on metals. The SOC 400 Surface Inspection Machine/InfraRed (SIMIR) has been developed as a nondestructive inspection tool to exploit this potential in practical situations. This SIMIR is a complete and ruggidized Fourier transform infrared spectrometer with a very efficient and robust barrel ellipse diffuse reflectance optical collection system and operating software system. The SIMIR weighs less than 8 Kg, occupies less than 14 L volume, and may be manipulated into any orientation during operation. The surface to be inspected is placed at the focal point of the SIMIR by manipulating the SIMIR or the surface. The SIMIR may or may not contact the surface being inspected. For flat or convex items, there are no size limits to items being inspected. For concave surfaces, the SIMIR geometry limits the surface to those having a radius of curvature greater than 0.2 m. For highly reflective metal surfaces, the SIMIR has a noise level approaching 1 {times} 10{sup {minus}4} absorbance units, which is sufficient for detecting nanometer thick organic film residues on metals. The use of this nondestructive inspection tool is demonstrated by the spatial mapping of organic stains on sand blasted metals in which organic stains such as silicone oils, mineral oils, and triglycerides are identified both qualitatively and quantitatively over the surface of the metal specimen.

  7. Recent progress in noninvasive diabetes screening by diffuse reflectance near-infrared skin spectroscopy

    NASA Astrophysics Data System (ADS)

    Heise, H. M.; Haiber, S.; Licht, M.; Ihrig, D. F.; Moll, C.; Stuecker, M.

    2006-02-01

    Near infrared spectroscopy exhibits a tremendous potential for clinical chemistry and tissue pathology. Owing to its penetration depth into human skin, near infrared radiation can probe chemical and structural information non-invasively. Metabolic diseases such as diabetes mellitus increase nonenzymatic glycation with the effect of glucose molecules bonding chemically to proteins. In addition, glycation accumulates on tissue proteins with the clearest evidence found in extracellular skin collagen, affecting also covalent crosslinking between adjacent protein strands, which reduces their flexibility, elasticity, and functionality. Non-enzymatically glycated proteins in human skin and following chemical and structural skin changes were our spectroscopic target. We carried out measurements on 109 subjects using two different NIR-spectrometers equipped with diffuse reflection accessories. Spectra of different skin regions (finger and hand/forearm skin) were recorded for comparison with clinical blood analysis data and further patient information allowing classification into diabetics and non-diabetics. Multivariate analysis techniques for supervised classification such as linear discriminant analysis (LDA) were applied using broad spectral interval data or a number of optimally selected wavelengths. Based on fingertip skin spectra recorded by fiber-optics, it was possible to classify diabetics and non-diabetics with a maximum accuracy of 87.8 % using leave-5-out cross-validation (sensitivity of 87.5. %, specificity of 88.2 %). With the results of this study, it can be concluded that ageing and glycation at elevated levels cannot always be separated from each other.

  8. Application of near infrared reflectance spectroscopy to predict meat and meat products quality: A review.

    PubMed

    Prieto, N; Roehe, R; Lavín, P; Batten, G; Andrés, S

    2009-10-01

    Over the past three decades, near infrared reflectance (NIR) spectroscopy has been proved to be one of the most efficient and advanced tools for the estimation of quality attributes in meat and meat products. This review focuses on the use of NIR spectroscopy to predict different meat properties, considering the literature published mainly in the last decade. Firstly, the potential of NIR to predict chemical composition (crude protein, intramuscular fat, moisture/dry matter, ash, gross energy, myoglobin and collagen), technological parameters (pH value; L*, a*, b* colour values; water holding capacity; Warner-Bratzler and slice shear force) and sensory attributes (colour, shape, marbling, odour, flavour, juiciness, tenderness or firmness) are reviewed. Secondly, the usefulness of NIR for classification into meat quality grades is presented and thirdly its potential application in the industry is shown. The review indicates that NIR showed high potential to predict chemical meat properties and to categorize meat into quality classes. In contrast, NIR showed limited ability for estimating technological and sensory attributes, which may be mainly due to the heterogeneity of the meat samples and their preparation, the low precision of the reference methods and the subjectivity of assessors in taste panels. Hence, future work to standardize sample preparation and increase the accuracy of reference methods is recommended to improve NIR ability to predict those technological and sensory characteristics. In conclusion, the review shows that NIR has a considerable potential to predict simultaneously numerous meat quality criteria. PMID:20416766

  9. Quantifying amyloid fibrils in protein mixtures via infrared attenuated-total-reflection spectroscopy.

    PubMed

    Wang, Pei; Bohr, Wilhelm; Otto, Markus; Danzer, Karin M; Mizaikoff, Boris

    2015-05-01

    Amyloid aggregation of proteins is usually associated with amyloid diseases. A distinct feature of protein aggregation is the increase of crossed β-sheet structures. Infrared attenuated-total-reflectance (IR-ATR) spectroscopy is a sensitive optical technique that has the potential to provide secondary structure characteristics of proteins even in complex biological samples. In this study we report the analysis of secondary structures of proteins, using the amide I band for the detection and quantification of amyloid fibrils in protein mixtures by use of IR-ATR techniques, at comparatively low sample concentrations. From the experimental results, an analytical model of the relationship between the IR spectra of protein mixtures and the individual mixture components was established using spectral-deconvolution procedures and curve-fitting methods. On the basis of this model, four ratios were shown to provide direct information on amyloid aggregated fibrils via the increase of crossed β-sheet structures in protein-mixture samples. In conclusion, this study confirms the utility of IR spectroscopy for analyzing protein mixtures and for identifying amyloid fibril information within such complex multi-component samples.

  10. Application of near infrared reflectance spectroscopy to predict meat and meat products quality: A review.

    PubMed

    Prieto, N; Roehe, R; Lavín, P; Batten, G; Andrés, S

    2009-10-01

    Over the past three decades, near infrared reflectance (NIR) spectroscopy has been proved to be one of the most efficient and advanced tools for the estimation of quality attributes in meat and meat products. This review focuses on the use of NIR spectroscopy to predict different meat properties, considering the literature published mainly in the last decade. Firstly, the potential of NIR to predict chemical composition (crude protein, intramuscular fat, moisture/dry matter, ash, gross energy, myoglobin and collagen), technological parameters (pH value; L*, a*, b* colour values; water holding capacity; Warner-Bratzler and slice shear force) and sensory attributes (colour, shape, marbling, odour, flavour, juiciness, tenderness or firmness) are reviewed. Secondly, the usefulness of NIR for classification into meat quality grades is presented and thirdly its potential application in the industry is shown. The review indicates that NIR showed high potential to predict chemical meat properties and to categorize meat into quality classes. In contrast, NIR showed limited ability for estimating technological and sensory attributes, which may be mainly due to the heterogeneity of the meat samples and their preparation, the low precision of the reference methods and the subjectivity of assessors in taste panels. Hence, future work to standardize sample preparation and increase the accuracy of reference methods is recommended to improve NIR ability to predict those technological and sensory characteristics. In conclusion, the review shows that NIR has a considerable potential to predict simultaneously numerous meat quality criteria.

  11. [Fast determination of induction period of motor gasoline using Fourier transform attenuated total reflection infrared spectroscopy].

    PubMed

    Liu, Ya-Fei; Yuan, Hong-Fu; Song, Chun-Feng; Xie, Jin-Chun; Li, Xiao-Yu; Yan, De-Lin

    2014-11-01

    A new method is proposed for the fast determination of the induction period of gasoline using Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR). A dedicated analysis system with the function of spectral measurement, data processing, display and storage was designed and integrated using a Fourier transform infrared spectrometer module and chemometric software. The sample presentation accessory designed which has advantages of constant optical path, convenient sample injection and cleaning is composed of a nine times reflection attenuated total reflectance (ATR) crystal of zinc selenide (ZnSe) coated with a diamond film and a stainless steel lid with sealing device. The influence of spectral scanning number and repeated sample loading times on the spectral signal-to-noise ratio was studied. The optimum spectral scanning number is 15 times and the optimum sample loading number is 4 times. Sixty four different gasoline samples were collected from the Beijing-Tianjin area and the induction period values were determined as reference data by standard method GB/T 8018-87. The infrared spectra of these samples were collected in the operating condition mentioned above using the dedicated fast analysis system. Spectra were pretreated using mean centering and 1st derivative to reduce the influence of spectral noise and baseline shift A PLS calibration model for the induction period was established by correlating the known induction period values of the samples with their spectra. The correlation coefficient (R2), standard error of calibration (SEC) and standard error of prediction (SEP) of the model are 0.897, 68.3 and 91.9 minutes, respectively. The relative deviation of the model for gasoline induction period prediction is less than 5%, which meets the requirements of repeatability tolerance in GB method. The new method is simple and fast. It takes no more than 3 minutes to detect one sample. Therefore, the method is feasible for implementing

  12. Rapid estimation of nutritional elements on citrus leaves by near infrared reflectance spectroscopy

    PubMed Central

    Galvez-Sola, Luis; García-Sánchez, Francisco; Pérez-Pérez, Juan G.; Gimeno, Vicente; Navarro, Josefa M.; Moral, Raul; Martínez-Nicolás, Juan J.; Nieves, Manuel

    2015-01-01

    Sufficient nutrient application is one of the most important factors in producing quality citrus fruits. One of the main guides in planning citrus fertilizer programs is by directly monitoring the plant nutrient content. However, this requires analysis of a large number of leaf samples using expensive and time-consuming chemical techniques. Over the last 5 years, it has been demonstrated that it is possible to quantitatively estimate certain nutritional elements in citrus leaves by using the spectral reflectance values, obtained by using near infrared reflectance spectroscopy (NIRS). This technique is rapid, non-destructive, cost-effective and environmentally friendly. Therefore, the estimation of macro and micronutrients in citrus leaves by this method would be beneficial in identifying the mineral status of the trees. However, to be used effectively NIRS must be evaluated against the standard techniques across different cultivars. In this study, NIRS spectral analysis, and subsequent nutrient estimations for N, K, Ca, Mg, B, Fe, Cu, Mn, and Zn concentration, were performed using 217 leaf samples from different citrus trees species. Partial least square regression and different pre-processing signal treatments were used to generate the best estimation against the current best practice techniques. It was verified a high proficiency in the estimation of N (Rv = 0.99) and Ca (Rv = 0.98) as well as achieving acceptable estimation for K, Mg, Fe, and Zn. However, no successful calibrations were obtained for the estimation of B, Cu, and Mn. PMID:26257767

  13. Characterization of historic silk by polarized attenuated total reflectance Fourier transform infrared spectroscopy for informed conservation.

    PubMed

    Garside, Paul; Lahlil, Sophia; Wyeth, Paul

    2005-10-01

    When assessing historic textiles and considering appropriate conservation, display, and storage strategies, characterizing the physical condition of the textiles is essential. Our work has concentrated on developing nondestructive or micro-destructive methodologies that will permit this. Previously, we have demonstrated a correlation between the physical deterioration of unweighted and "pink" tin (IV) chloride weighted silk and certain measurable spectroscopic and chromatographic signatures, derived from polarized Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy (Pol-ATR) and high-performance liquid chromatography (HPLC) microsampling analyses. The application of the Pol-ATR technique to aged silk characterization has now been extended to include a more comprehensive range of weighting methods and aging regimes. This was intended to replicate the full spectrum of states of deterioration observed in silk textiles, from pristine to heavily degraded. Breaking strength was employed as a measure of the physical integrity of the fibers, and, as expected, decreased with aging. An orientational crystallinity parameter, reflecting the microstructural ordering of the fibroin polymer within the fibers, was derived from the Pol-ATR spectra. A good correlation was observed between the breaking strength of the variety of fibers and this parameter. This suggests that the physical state of historic silk fabrics might be adequately characterized for conservation purposes by such indirect micromethodology.

  14. Improved depth resolution in near-infrared diffuse reflectance spectroscopy using obliquely oriented fibers

    NASA Astrophysics Data System (ADS)

    Thilwind, Rachel Estelle; 't Hooft, Gert; Uzunbajakava, Natallia E.

    2009-03-01

    We demonstrate a significant improvement of depth selectivity when using obliquely oriented fibers for near-infrared (NIR) diffuse reflectance spectroscopy. This is confirmed by diffuse reflectance measurements of a two-layer tissue-mimicking phantom across the spectral range from 1000 to 1940 nm. The experimental proof is supported by Monte Carlo simulations. The results reveal up to fourfold reduction in the mean optical penetration depth, twofold reduction in its variation, and a decrease in the number of scattering events when a single fiber is oriented at an angle of 60 deg. The effect of reducing the mean optical penetration depth is enhanced by orienting both fibers inwardly. Using outwardly oriented fibers enables more selective probing of deeper layers, while reducing the contribution from surface layers. We further demonstrate that the effect of an inward oblique arrangement can be approximated to a decrease in fiber-to-fiber separation in the case of a perpendicular fiber arrangement. This approximation is valid in the weak- or absorption-free regime. Our results assert the advantages of using obliquely oriented fibers when attempting to specifically address superficial tissue layers, for example, for skin cancer detection, or in noninvasive glucose monitoring. Such flexibility could be further advantageous in a range of minimally invasive applications, including catheter-based interventions.

  15. Comparison of visible and near infrared reflectance spectroscopy on fat to authenticate dietary history of lambs.

    PubMed

    Huang, Y; Andueza, D; de Oliveira, L; Zawadzki, F; Prache, S

    2015-11-01

    Since consumers are showing increased interest in the origin and method of production of their food, it is important to be able to authenticate dietary history of animals by rapid and robust methods used in the ruminant products. Promising breakthroughs have been made in the use of spectroscopic methods on fat to discriminate pasture-fed and concentrate-fed lambs. However, questions remained on their discriminatory ability in more complex feeding conditions, such as concentrate-finishing after pasture-feeding. We compared the ability of visible reflectance spectroscopy (Vis RS, wavelength range: 400 to 700 nm) with that of visible-near-infrared reflectance spectroscopy (Vis-NIR RS, wavelength range: 400 to 2500 nm) to differentiate between carcasses of lambs reared with three feeding regimes, using partial least square discriminant analysis (PLS-DA) as a classification method. The sample set comprised perirenal fat of Romane male lambs fattened at pasture (P, n = 69), stall-fattened indoors on commercial concentrate and straw (S, n = 55) and finished indoors with concentrate and straw for 28 days after pasture-feeding (PS, n = 65). The overall correct classification rate was better for Vis-NIR RS than for Vis RS (99.0% v. 95.1%, P < 0.05). Vis-NIR RS allowed a correct classification rate of 98.6%, 100.0% and 98.5% for P, S and PS lambs, respectively, whereas Vis RS allowed a correct classification rate of 98.6%, 94.5% and 92.3% for P, S and PS lambs, respectively. This study suggests the likely implication of molecules absorbing light in the non-visible part of the Vis-NIR spectra (possibly fatty acids), together with carotenoid and haem pigments, in the discrimination of the three feeding regimes.

  16. Enhanced single seed trait predictions in soybean (Glycine max) and robust calibration model transfer with near infrared reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Single seed near infrared reflectance (NIR) spectroscopy predicts soybean (Glycine max) seed quality traits of moisture, oil, and protein. We tested the accuracy of transferring calibrations between different single seed NIR analyzers of the same design by collecting NIR spectra and analytical trait...

  17. Secondary cell wall development in cotton fibers as examined with attenuated total reflection Fourier transform infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering were examined using attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy. The selected harvesting points coincide with secondary cell wall (SCW) development in the fibers. Progressive but moderat...

  18. Fourier transform infrared spectroscopy

    SciTech Connect

    Ferraro, J.R.; Basile, L.J.

    1985-01-01

    The final and largest volume to complete this four-volume treatise is published in response to the intense commercial and research interest in Fourier Transform Interferometry. Volume 4 introduces new information on, for example, applications of Diffuse Reflectance Spectroscopy in the Far-infrared Region. The editors place emphasis on surface studies and address advances in Capillary Gas Chromatography-Fourier Transform Interferometry.

  19. Historical perspective and modern applications of Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR).

    PubMed

    Blum, Marc-Michael; John, Harald

    2012-01-01

    Vibrational spectroscopy has a long history as an important spectroscopic method in chemical and pharmaceutical analysis. Instrumentation for infrared (IR) spectroscopy was revolutionized by the introduction of Fourier Transform Infrared (FTIR) spectrometers. In addition, easier sampling combined with better sample-to-sample reproducibility and user-to-user spectral variation became available with attenuated total reflectance (ATR) probes and their application for in situ IR spectroscopy. These innovations allow many new applications in chemical and pharmaceutical analysis, such as the use of IR spectroscopy in Process Analytical Chemistry (PAC), the quantitation of drugs in complex matrix formulations, the analysis of protein binding and function and in combination with IR microscopy to the emergence of IR imaging technologies. The use of ATR-FTIR instruments in forensics and first response to 'white powder' incidents is also discussed. A short overview is given in this perspective article with the aim to renew and intensify interest in IR spectroscopy.

  20. Optical diffuse reflectance accessory for measurements of skin tissue by near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Marbach, R.; Heise, H. M.

    1995-02-01

    An optimized accessory for measuring the diffuse reflectance spectra of human skin tissue in the near-infrared spectral range is presented. The device includes an on-axis ellipsoidal collecting mirror with efficient illumination optics for small sampling areas of bulky body specimens. The optical design is supported by the results of a Monte Carlo simulation study of the reflectance characteristics of skin tissue. Because the results evolved from efforts to measure blood glucose noninvasively, the main emphasis is placed on the long-wavelength near-infrared range where sufficient penetration depth for radiation into tissue is still available. The accessory is applied for in vivo diffuse reflectance measurements.

  1. [Attenuated Total Reflection Infrared Spectroscopy for Degradation Profile of High Density Polyethylene after Weathering Aging].

    PubMed

    Guo, Jun-jun; Yan, Hua; Bao, He-bin; Wang, Xue-mei; Hu, Zhi-de; Yang, Jian-jian

    2015-06-01

    High density polyethylene (HDPE) was widely used as rotational packaging case in the material reserve field. The chemical changes of HDPE, exposed to particular climatic conditions of tropic marine atmosphere for one year-long in Wanning Hainan, were elucidated by the attenuated total reflection infrared spectroscopy (ATR-FTIR). The structural changes were studied qualitatively, mainly from the polymeric chain breaking, branching and oxidation to distinguish the degradation profile. The variations of crystallinity & carbonyl index were also studied quantitatively according to the characteristic peaks intensity & area ratio. Finally, the relationships between structural changes and mechanical properties were investigated. The results showed that the polymeric chain breaking & branching play a leading role before 3 months in the aging progress. Then oxidation phenomena gradually takes place during 3-6 months. The chain branching & oxidation were predominant factors after 6 months. Nine months later, the oxidation was saturated gradually. Furthermore, the aging process is positively correlated to the temperature and irradiation. After 12 months aging, the carbonyl index increased by 112 times and crystallinity was 10% higher than before. The tensile/bending modulus deceased faster than tensile/bending strength of HDPE. The linear degree of tensile modulus and carbonyl index was 0.97. The degree of linearity of tensile strength and crystallinity calculated by feature bands (720-730 cm(-1)) was 0.96. It showed that the mechanical properties of HDPE can be speculated from the structural changes by ATR-FTIR. PMID:26601359

  2. Characterization of early stage cartilage degradation using diffuse reflectance near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Brown, C. P.; Jayadev, C.; Glyn-Jones, S.; Carr, A. J.; Murray, D. W.; Price, A. J.; Gill, H. S.

    2011-04-01

    Interest in localized and early stage treatment technologies for joint conditions such as osteoarthritis is growing rapidly. It has therefore become important to develop objective measures capable of characterizing the earliest (non-visible) changes associated with degeneration to aid treatment procedures. In addition to assessing tissue before treatment, it is further important to develop an effective, non-destructive means of monitoring post-treatment tissue healing, and of providing the high-quality data needed for trials of developing treatment methods. To investigate its ability to detect the early stages of degeneration in cartilage-on-bone, diffuse reflectance near infrared spectroscopy was applied to normal and osteoarthritic joints. A discriminating function was developed to relate absorbance peaks of interest and track degradation around focal osteoarthritic defects. The function could distinguish between normal and degraded tissue (100% separation of normal tissue from that within 25 mm of a defect) and between different stages of osteoarthritic progression (p < 0.05). This technique allows simple, practical and non-destructive assessment of component-level properties over the full depth of the tissue. It has the potential to increase our understanding of the underlying etiologic and pathogenic processes in early stage degeneration, to assist classification and the development of new treatment methods.

  3. Attenuated total reflectance Fourier transform infrared spectroscopy method to differentiate between normal and cancerous breast cells.

    PubMed

    Lane, Randy; See, Seong S

    2012-09-01

    Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) is used to find the structural differences between cancerous breast cells (MCF-7 line) and normal breast cells (MCF-12F line). Gold nanoparticles were prepared and the hydrodynamic diameter of the gold nanoparticles found to be 38.45 nm. The Gold nanoparticles were exposed to both MCF-7 and MCF-12F cells from lower to higher concentrations. Spectroscopic studies founds nanoparticles were within the cells, and increasing the nanoparticles concentration inside the cells also resulted in sharper IR peaks as a result of localized surface Plasmon resonance. Asymmetric and symmetric stretching and bending vibrations between phosphate, COO-, CH2 groups were found to give negative shifts in wavenumbers and a decrease in peak intensities when going from noncancerous to cancerous cells. Cellular proteins produced peak assignments at the 1542 and 1644 cm(-1) wavenumbers which were attributed to the amide I and amide II bands of the polypeptide bond of proteins. Significant changes were found in the peak intensities between the cell lines in the spectrum range from 2854-2956 cm(-1). Results show that the concentration range of gold nanoparticles used in this research showed no significant changes in cell viability in either cell line. Therefore, we believe ATR-FTIR and gold nanotechnology can be at the forefront of cancer diagnosis for some time to come.

  4. Detection of sibutramine in adulterated dietary supplements using attenuated total reflectance-infrared spectroscopy.

    PubMed

    Deconinck, E; Cauwenbergh, T; Bothy, J L; Custers, D; Courselle, P; De Beer, J O

    2014-11-01

    Sibutramine is one of the most occurring adulterants encountered in dietary supplements with slimming as indication. These adulterated dietary supplements often contain a herbal matrix. When customs intercept these kind of supplements it is almost impossible to discriminate between the legal products and the adulterated ones, due to misleading packaging. Therefore in most cases these products are confiscated and send to laboratories for analysis. This results inherently in the confiscation of legal, non-adulterated products. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. Attenuated total reflectance-infrared (ATR-IR) spectroscopy was evaluated for the detection of sibutramine in adulterated dietary supplements. Data interpretation was performed using different basic chemometric techniques. It was found that the use of ATR-IR combined with the k-Nearest Neighbours (k-NN) was able to detect all adulterated dietary supplements in an external test set and this with a minimum of false positive results. This means that a small amount of legal products will still be confiscated and analyzed in a laboratory to be found negative, but no adulterated samples will pass the initial ATR-IR screening.

  5. Phase transitions of amorphous solid acetone in confined geometry investigated by reflection absorption infrared spectroscopy.

    PubMed

    Shin, Sunghwan; Kang, Hani; Kim, Jun Soo; Kang, Heon

    2014-11-26

    We investigated the phase transformations of amorphous solid acetone under confined geometry by preparing acetone films trapped in amorphous solid water (ASW) or CCl4. Reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) were used to monitor the phase changes of the acetone sample with increasing temperature. An acetone film trapped in ASW shows an abrupt change in the RAIRS features of the acetone vibrational bands during heating from 80 to 100 K, which indicates the transformation of amorphous solid acetone to a molecularly aligned crystalline phase. Further heating of the sample to 140 K produces an isotropic solid phase, and eventually a fluid phase near 157 K, at which the acetone sample is probably trapped in a pressurized, superheated condition inside the ASW matrix. Inside a CCl4 matrix, amorphous solid acetone crystallizes into a different, isotropic structure at ca. 90 K. We propose that the molecularly aligned crystalline phase formed in ASW is created by heterogeneous nucleation at the acetone-water interface, with resultant crystal growth, whereas the isotropic crystalline phase in CCl4 is formed by homogeneous crystal growth starting from the bulk region of the acetone sample.

  6. [Discriminant Analysis of Lavender Essential Oil by Attenuated Total Reflectance Infrared Spectroscopy].

    PubMed

    Tang, Jun; Wang, Qing; Tong, Hong; Liao, Xiang; Zhang, Zheng-fang

    2016-03-01

    This work aimed to use attenuated total reflectance Fourier transform infrared spectroscopy to identify the lavender essential oil by establishing a Lavender variety and quality analysis model. So, 96 samples were tested. For all samples, the raw spectra were pretreated as second derivative, and to determine the 1 750-900 cm(-1) wavelengths for pattern recognition analysis on the basis of the variance calculation. The results showed that principal component analysis (PCA) can basically discriminate lavender oil cultivar and the first three principal components mainly represent the ester, alcohol and terpenoid substances. When the orthogonal partial least-squares discriminant analysis (OPLS-DA) model was established, the 68 samples were used for the calibration set. Determination coefficients of OPLS-DA regression curve were 0.959 2, 0.976 4, and 0.958 8 respectively for three varieties of lavender essential oil. Three varieties of essential oil's the root mean square error of prediction (RMSEP) in validation set were 0.142 9, 0.127 3, and 0.124 9, respectively. The discriminant rate of calibration set and the prediction rate of validation set had reached 100%. The model has the very good recognition capability to detect the variety and quality of lavender essential oil. The result indicated that a model which provides a quick, intuitive and feasible method had been built to discriminate lavender oils. PMID:27400512

  7. [Near-infrared reflectance spectroscopy analytic model established for the IVDMD of Cichorium intybus L].

    PubMed

    Hu, Chao; Bai, Shi-qie; Zhang, Yu; Yan, Jia-jun; You, Ming-hong; Li, Da-xu; Bai, Ling; Zhang Jin

    2014-08-01

    Chicory (Cichorium intybus L.) is a new type of forage grasses of high yield and quality with a great value of popularization and utilization. In vitro dry matter digestibility (IVDMD) is one of the important indicators of the nutritional value of forage evaluation. For the study of establishment of Chicory IVDMD NIRS quantitative analysis model, seventy-two species with different genotypes, different growth stages of 204 chicory samples of aboveground material were collected, and by Fourier transform near-infrared diffuse reflectance spectroscopy, through the use of different regression algorithms, can comparing different spectral ranges and spectral pretreatment methods, eight chicory IVDMD NIRS calibration models were established, and the best calibration model parameters were chosen. Its calibration coefficient of determination (Ri) and external validation coefficient of determination (Rval2) were 0.95317 and 0.90455, calibration standard deviation (RMSEC) and predictive standard deviation (RMSEP) was 1.977 99% and 2.008 82%, and the correlation coefficient (r) between predicted values and chemical values was 0.95108. The results show that using NIRS to determine chicory IVDMD is feasible, and provided a rapid analysis method for the determination IVDMD of chicory. PMID:25508718

  8. [Attenuated Total Reflection Infrared Spectroscopy for Degradation Profile of High Density Polyethylene after Weathering Aging].

    PubMed

    Guo, Jun-jun; Yan, Hua; Bao, He-bin; Wang, Xue-mei; Hu, Zhi-de; Yang, Jian-jian

    2015-06-01

    High density polyethylene (HDPE) was widely used as rotational packaging case in the material reserve field. The chemical changes of HDPE, exposed to particular climatic conditions of tropic marine atmosphere for one year-long in Wanning Hainan, were elucidated by the attenuated total reflection infrared spectroscopy (ATR-FTIR). The structural changes were studied qualitatively, mainly from the polymeric chain breaking, branching and oxidation to distinguish the degradation profile. The variations of crystallinity & carbonyl index were also studied quantitatively according to the characteristic peaks intensity & area ratio. Finally, the relationships between structural changes and mechanical properties were investigated. The results showed that the polymeric chain breaking & branching play a leading role before 3 months in the aging progress. Then oxidation phenomena gradually takes place during 3-6 months. The chain branching & oxidation were predominant factors after 6 months. Nine months later, the oxidation was saturated gradually. Furthermore, the aging process is positively correlated to the temperature and irradiation. After 12 months aging, the carbonyl index increased by 112 times and crystallinity was 10% higher than before. The tensile/bending modulus deceased faster than tensile/bending strength of HDPE. The linear degree of tensile modulus and carbonyl index was 0.97. The degree of linearity of tensile strength and crystallinity calculated by feature bands (720-730 cm(-1)) was 0.96. It showed that the mechanical properties of HDPE can be speculated from the structural changes by ATR-FTIR.

  9. Detection of sibutramine in adulterated dietary supplements using attenuated total reflectance-infrared spectroscopy.

    PubMed

    Deconinck, E; Cauwenbergh, T; Bothy, J L; Custers, D; Courselle, P; De Beer, J O

    2014-11-01

    Sibutramine is one of the most occurring adulterants encountered in dietary supplements with slimming as indication. These adulterated dietary supplements often contain a herbal matrix. When customs intercept these kind of supplements it is almost impossible to discriminate between the legal products and the adulterated ones, due to misleading packaging. Therefore in most cases these products are confiscated and send to laboratories for analysis. This results inherently in the confiscation of legal, non-adulterated products. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. Attenuated total reflectance-infrared (ATR-IR) spectroscopy was evaluated for the detection of sibutramine in adulterated dietary supplements. Data interpretation was performed using different basic chemometric techniques. It was found that the use of ATR-IR combined with the k-Nearest Neighbours (k-NN) was able to detect all adulterated dietary supplements in an external test set and this with a minimum of false positive results. This means that a small amount of legal products will still be confiscated and analyzed in a laboratory to be found negative, but no adulterated samples will pass the initial ATR-IR screening. PMID:25173110

  10. Attenuated total reflection (ATR) Fourier transform infrared spectroscopy of dimyristoyl phosphatidylserine-cholesterol mixtures.

    PubMed

    Bach, D; Miller, I R

    2001-10-01

    Mixtures of cholesterol with dimyristoyl phosphatidylserine or deuterated dimyristoyl phosphatidylserine were investigated by polarized and non polarized attenuated total reflection (ATR) Fourier transform infrared (FTIR) Spectroscopy. From polarized spectra the dichroic ratios of various vibrations as a function of cholesterol were calculated. Dichroic ratios of methylene vibration (CH(2)) 2934 cm(-1) of cholesterol decreases with increase of cholesterol concentration leveling off in the region where cholesterol phase separation takes place. The orientation of deuterated methylene (CD(2)) symmetric and asymmetric bands of the deuterated dimyristoyl phosphatidylserine is influenced little by cholesterol. In the polar region of dimyristoyl phosphatidylserine no effect of cholesterol on the dichroic ratios of carbonyl (C==O) and asymmetric phosphate (PO(2)(-)) vibrations were detected. For nonpolarized spectra the broad bands in the polar region of the phospholipid were deconvoluted. The carbonyl band (C==O) in pure dimyristoyl phosphatidylserine is composed of five bands; in the presence of increasing concentrations of cholesterol conformational change of these vibrations takes place evolving into one predominant band. Similar conformational change takes place in the presence of 75 molecules water/molecule DMPS. For the asymmetric phosphate band very small shifts due to interaction with cholesterol were detected.

  11. Rapid Assessment of Mineral Concentration in Meadow Grasses by Near Infrared Reflectance Spectroscopy

    PubMed Central

    Ward, Alastair; Nielsen, Anne Lisbeth; Møller, Henrik

    2011-01-01

    A near infrared reflectance spectroscopy (NIRS) method for rapid determination of nitrogen, phosphorous and potassium in diverse meadow grasses was developed with a view towards utilizing this material for biogas production and organic fertilizer. NIRS spectra between 12,000 cm−1 and 4,000 cm−1 were used. When validated on samples from different years to those used for the calibration set, the NIRS prediction of nitrogen was considered moderately useful with R2 = 0.77, ratio of standard error of prediction to reference data range (RER) of 9.32 and ratio of standard error of prediction to standard deviation of reference data (RPD) of 2.33. Prediction of potassium was less accurate, with R2 = 0.77, RER of 6.56 and RPD of 1.45, whilst prediction of phosphorous was not considered accurate enough to be of any practical use. This work is of interest from the point of view of both the removal of excess nutrients from formerly intensively farmed areas and also for assessing the plant biomass suitability for conversion into carbon neutral energy through biogas production. PMID:22163878

  12. Forensic Hair Differentiation Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy.

    PubMed

    Manheim, Jeremy; Doty, Kyle C; McLaughlin, Gregory; Lednev, Igor K

    2016-07-01

    Hair and fibers are common forms of trace evidence found at crime scenes. The current methodology of microscopic examination of potential hair evidence is absent of statistical measures of performance, and examiner results for identification can be subjective. Here, attenuated total reflection (ATR) Fourier transform-infrared (FT-IR) spectroscopy was used to analyze synthetic fibers and natural hairs of human, cat, and dog origin. Chemometric analysis was used to differentiate hair spectra from the three different species, and to predict unknown hairs to their proper species class, with a high degree of certainty. A species-specific partial least squares discriminant analysis (PLSDA) model was constructed to discriminate human hair from cat and dog hairs. This model was successful in distinguishing between the three classes and, more importantly, all human samples were correctly predicted as human. An external validation resulted in zero false positive and false negative assignments for the human class. From a forensic perspective, this technique would be complementary to microscopic hair examination, and in no way replace it. As such, this methodology is able to provide a statistical measure of confidence to the identification of a sample of human, cat, and dog hair, which was called for in the 2009 National Academy of Sciences report. More importantly, this approach is non-destructive, rapid, can provide reliable results, and requires no sample preparation, making it of ample importance to the field of forensic science. PMID:27412186

  13. Quantitative orientation measurements in thin lipid films by attenuated total reflection infrared spectroscopy.

    PubMed Central

    Picard, F; Buffeteau, T; Desbat, B; Auger, M; Pézolet, M

    1999-01-01

    Quantitative orientation measurements by attenuated total reflectance (ATR) infrared spectroscopy require the accurate knowledge of the dichroic ratio and of the mean-square electric fields along the three axes of the ATR crystal. In this paper, polarized ATR spectra of single supported bilayers of the phospholipid dimyristoylphosphatidic acid covered by either air or water have been recorded and the dichroic ratio of the bands due to the methylene stretching vibrations has been calculated. The mean-square electric field amplitudes were calculated using three formalisms, namely the Harrick thin film approximation, the two-phase approximation, and the thickness- and absorption-dependent one. The results show that for dry bilayers, the acyl chain tilt angle varies with the formalism used, while no significant variations are observed for the hydrated bilayers. To test the validity of the different formalisms, s- and p-polarized ATR spectra of a 40-A lipid layer were simulated for different acyl chain tilt angles. The results show that the thickness- and absorption-dependent formalism using the mean values of the electric fields over the film thickness gives the most accurate values of acyl chain tilt angle in dry lipid films. However, for lipid monolayers or bilayers, the tilt angle can be determined with an acceptable accuracy using the Harrick thin film approximation. Finally, this study shows clearly that the uncertainty on the determination of the tilt angle comes mostly from the experimental error on the dichroic ratio and from the knowledge of the refractive index. PMID:9876167

  14. Detection of canine skin and subcutaneous tumors by visible and near-infrared diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Cugmas, Blaž; Plavec, Tanja; Bregar, Maksimilijan; Naglič, Peter; Pernuš, Franjo; Likar, Boštjan; Bürmen, Miran

    2015-03-01

    Cancer is the main cause of canine morbidity and mortality. The existing evaluation of tumors requires an experienced veterinarian and usually includes invasive procedures (e.g., fine-needle aspiration) that can be unpleasant for the dog and the owner. We investigate visible and near-infrared diffuse reflectance spectroscopy (DRS) as a noninvasive optical technique for evaluation and detection of canine skin and subcutaneous tumors ex vivo and in vivo. The optical properties of tumors and skin were calculated in a spectrally constrained manner, using a lookup table-based inverse model. The obtained optical properties were analyzed and compared among different tumor groups. The calculated parameters of the absorption and reduced scattering coefficients were subsequently used for detection of malignant skin and subcutaneous tumors. The detection sensitivity and specificity of malignant tumors ex vivo were 90.0% and 73.5%, respectively, while corresponding detection sensitivity and specificity of malignant tumors in vivo were 88.4% and 54.6%, respectively. The obtained results show that the DRS is a promising noninvasive optical technique for detection and classification of malignant and benign canine skin and subcutaneous tumors. The method should be further investigated on tumors with common origin.

  15. Adsorption on carbon nanotubes studied using polarization-modulated infrared reflection-absorption spectroscopy.

    PubMed

    Bermudez, V M

    2005-05-26

    Single-wall carbon nanotubes (SWNTs), deposited onto an Al substrate from a liquid suspension, have been cleaned by annealing in ultrahigh vacuum. The effects of exposing the sample in situ to atomic H (or D) and/or to dimethyl methylphosphonate [DMMP, (CH(3)O)(2)(CH(3))P=O] were then studied using polarization-modulated infrared reflection-absorption spectroscopy. Atomic H reacts preferentially near strained or defective regions in the nanotube wall to produce a spectrum consistent with alkane-like species (>CH(2) and -CH(3)). Only a small fraction of the >C=C< sites in the nanotube wall react with H, and there is no clear evidence for monohydride >C(H)-C(H)< species. For DMMP, data were obtained under steady-state conditions in reagent pressures in excess of half the room-temperature vapor pressure. Adsorption occurs via the P=O group with a coverage that depends on the ambient pressure. Varying the DMMP coverage by changing the pressure causes changes in the spectrum that can be related to the strength of the DMMP/SWNT interaction. Preadsorbed H is seen to have little or no effect on the subsequent adsorption of DMMP. For DMMP, the molecular features are superimposed on a broad, smoothly varying background that can be related to adsorption-induced changes in the Drude parameters characterizing the SWNT free-carrier density and scattering lifetime.

  16. Crop/weed discrimination using near-infrared reflectance spectroscopy (NIRS)

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; He, Yong

    2006-09-01

    The traditional uniform herbicide application often results in an over chemical residues on soil, crop plants and agriculture produce, which have imperiled the environment and food security. Near-infrared reflectance spectroscopy (NIRS) offers a promising means for weed detection and site-specific herbicide application. In laboratory, a total of 90 samples (30 for each species) of the detached leaves of two weeds, i.e., threeseeded mercury (Acalypha australis L.) and fourleafed duckweed (Marsilea quadrfolia L.), and one crop soybean (Glycine max) was investigated for NIRS on 325- 1075 nm using a field spectroradiometer. 20 absorbance samples of each species after pretreatment were exported and the lacked Y variables were assigned independent values for partial least squares (PLS) analysis. During the combined principle component analysis (PCA) on 400-1000 nm, the PC1 and PC2 could together explain over 91% of the total variance and detect the three plant species with 98.3% accuracy. The full-cross validation results of PLS, i.e., standard error of prediction (SEP) 0.247, correlation coefficient (r) 0.954 and root mean square error of prediction (RMSEP) 0.245, indicated an optimum model for weed identification. By predicting the remaining 10 samples of each species in the PLS model, the results with deviation presented a 100% crop/weed detection rate. Thus, it could be concluded that PLS was an available alternative of for qualitative weed discrimination on NTRS.

  17. Near infrared reflectance spectroscopy for the fast identification of PVC-based films.

    PubMed

    Laasonen, M; Rantanen, J; Harmia-Pulkkinen, T; Michiels, E; Hiltunen, R; Räsänen, M; Vuorela, H

    2001-07-01

    Near infrared (NIR) reflectance spectroscopy was used to develop a non-destructive and rapid qualitative method for the analysis of plastic films used by the pharmaceutical industry for blistering. Three types of films were investigated: 250 microm PVC [poly(vinyl chloride)] films, 250 microm PVC films coated with 40 g m(-2) of PVDC [poly(vinylidene dichloride)] and 250 microm PVC films coated with 5 g m(-2) of TE (Thermoelast) and 90 g m(-2) of PVDC. Three analyses were carried out using different pre-treatment options and a PLS (partial least squares) algorithm. Each analysis was aimed at identifying one type of film and rejecting all types of false sample (different thickness, colour or layer). True and false samples from four plastics manufacturers were included in the calibration sets in order to obtain robust methods that were suitable regardless of the supplier. Specificity was demonstrated by testing validation sets against the methods. The tests showed 0% of type I (false negative identification) and 1% of type II errors (false positive identification) for the PVC method, 13 and 3%, respectively, for the PVC-PVDC method and no error for the PVC-TE-PVDC method. Type II errors, mostly due to the slight sensitivity of the methods to film thickness, are easily corrected by simple thickness measurements. This study demonstrates that NIR spectroscopy is an excellent tool for the identification of PVC-based films. The three methods can be used by the pharmaceutical industry or plastics manufacturers for the quality control of films used in blister packaging.

  18. Quantification of bovine immunoglobulin G using transmission and attenuated total reflectance infrared spectroscopy.

    PubMed

    Elsohaby, Ibrahim; McClure, J Trenton; Riley, Christopher B; Shaw, R Anthony; Keefe, Gregory P

    2016-01-01

    In this study, we evaluated and compared the performance of transmission and attenuated total reflectance (ATR) infrared (IR) spectroscopic methods (in combination with quantification algorithms previously developed using partial least squares regression) for the rapid measurement of bovine serum immunoglobulin G (IgG) concentration, and detection of failure of transfer of passive immunity (FTPI) in dairy calves. Serum samples (n = 200) were collected from Holstein calves 1-11 days of age. Serum IgG concentrations were measured by the reference method of radial immunodiffusion (RID) assay, transmission IR (TIR) and ATR-IR spectroscopy-based assays. The mean IgG concentration measured by RID was 17.22 g/L (SD ±9.60). The mean IgG concentrations predicted by TIR and ATR-IR spectroscopy methods were 15.60 g/L (SD ±8.15) and 15.94 g/L (SD ±8.66), respectively. RID IgG concentrations were positively correlated with IgG levels predicted by TIR (r = 0.94) and ATR-IR (r = 0.92). The correlation between 2 IR spectroscopic methods was 0.94. Using an IgG concentration <10 g/L as the cut-point for FTPI cases, the overall agreement between TIR and ATR-IR methods was 94%, with a corresponding kappa value of 0.84. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for identifying FTPI by TIR were 0.87, 0.97, 0.91, 0.95, and 0.94, respectively. Corresponding values for ATR-IR were 0.87, 0.95, 0.86, 0.95, and 0.93, respectively. Both TIR and ATR-IR spectroscopic approaches can be used for rapid quantification of IgG level in neonatal bovine serum and for diagnosis of FTPI in dairy calves.

  19. Total reflection infrared spectroscopy of water-ice and frozen aqueous NaCl solutions

    SciTech Connect

    Walker, Rachel L.; Searles, Keith; Willard, Jesse A.; Michelsen, Rebecca R. H.

    2013-12-28

    Liquid-like and liquid water at and near the surface of water-ice and frozen aqueous sodium chloride films were observed using attenuated total reflection infrared spectroscopy (ATR-IR). The concentration of NaCl ranged from 0.0001 to 0.01 M and the temperature varied from the melting point of water down to 256 K. The amount of liquid brine at the interface of the frozen films with the germanium ATR crystal increased with salt concentration and temperature. Experimental spectra are compared to reflection spectra calculated for a simplified morphology of a uniform liquid layer between the germanium crystal and the frozen film. This morphology allows for the amount of liquid observed in an experimental spectrum to be converted to the thickness of a homogenous layer with an equivalent amount of liquid. These equivalent thickness ranges from a nanometer for water-ice at 260 K to 170 nm for 0.01 M NaCl close to the melting point. The amounts of brine observed are over an order of magnitude less than the total liquid predicted by equilibrium thermodynamic models, implying that the vast majority of the liquid fraction of frozen solutions may be found in internal inclusions, grain boundaries, and the like. Thus, the amount of liquid and the solutes dissolved in them that are available to react with atmospheric gases on the surfaces of snow and ice are not well described by thermodynamic equilibrium models which assume the liquid phase is located entirely at the surface.

  20. Analysis of total oil and fatty acids composition by near infrared reflectance spectroscopy in edible nuts

    NASA Astrophysics Data System (ADS)

    Kandala, Chari V.; Sundaram, Jaya

    2014-10-01

    Near Infrared (NIR) Reflectance spectroscopy has established itself as an important tool in quantifying water and oil present in various food materials. It is rapid and nondestructive, easier to use, and does not require processing the samples with corrosive chemicals that would render them non-edible. Earlier, the samples had to be ground into powder form before making any measurements. With the development of new soft ware packages, NIR techniques could now be used in the analysis of intact grain and nuts. While most of the commercial instruments presently available work well with small grain size materials such as wheat and corn, the method present here is suitable for large kernel size products such as shelled or in-shell peanuts. Absorbance spectra were collected from 400 nm to 2500 nm using a NIR instrument. Average values of total oil contents (TOC) of peanut samples were determined by standard extraction methods, and fatty acids were determined using gas chromatography. Partial least square (PLS) analysis was performed on the calibration set of absorption spectra, and models were developed for prediction of total oil and fatty acids. The best model was selected based on the coefficient of determination (R2), Standard error of prediction (SEP) and residual percent deviation (RPD) values. Peanut samples analyzed showed RPD values greater than 5.0 for both absorbance and reflectance models and thus could be used for quality control and analysis. Ability to rapidly and nondestructively measure the TOC, and analyze the fatty acid composition, will be immensely useful in peanut varietal improvement as well as in the grading process of grain and nuts.

  1. Hygrothermal degradation of 3-glycidoxypropyltrimethoxysilane films studied by neutron and X-ray reflectivity and attenuated total reflection infrared spectroscopy.

    SciTech Connect

    Tallant, David Robert; Garcia, Manuel Joseph; Majewski, Jaroslaw; Kent, Michael Stuart; Yim, Hyun

    2005-05-01

    Thin films of organosilanes have great technological importance in the areas of adhesion promotion, durability, and corrosion resistance. However, it is well-known that water can degrade organosilane films, particularly at elevated temperatures. In this work, X-ray and neutron reflectivity (XR and NR) were combined with attenuated total reflection infrared (ATR-IR) spectroscopy to study the chemical and structural changes within thin films of (3-glycidoxypropyl)trimethoxysilane (GPS) after exposure for various periods of time to air saturated with either D{sub 2}O or H{sub 2}O at 80 C. For NR and XR, ultrathin ({approx}100 {angstrom}) films were prepared by spin-coating. Both D{sub 2}O and H{sub 2}O provide neutron scattering contrast with GPS. Variations in the neutron scattering length density (SLD) profiles (a function of mass density and atomic composition) with conditioning time were measured after drying the samples out and also swelled with H{sub 2}O or D{sub 2}O vapor at room temperature. For samples that were dried out prior to measurement, little or no change was observed for H{sub 2}O conditioning up to 3.5 days, but large changes were observed after 30 days of conditioning. The range of conditioning time for this structural change was narrowed to between 4 and 10 days with XR. The SLD profiles indicated that the top portion of the GPS film was transformed into a thick low-density layer after conditioning, but the bottom portion showed little structural change. A previous NR study of as-prepared GPS films involving swelling with deuterated nitrobenzene showed that the central portion of the film has much lower cross-link density than the region nearest the substrate. The present data show that the central portion also swells to a much greater extent with water and hydrolyzes more rapidly. The chemical degradation mechanism was identified by IR as hydrolysis of siloxane bonds. For ATR-IR, GPS films were prepared by dip-coating, which resulted in a greater

  2. Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.

    PubMed

    Monico, Letizia; Rosi, Francesca; Miliani, Costanza; Daveri, Alessia; Brunetti, Brunetto G

    2013-12-01

    In this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome artworks analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the νs(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks.

  3. The potential of near infrared reflectance spectroscopy (NIRS) for the estimation of agroindustrial compost quality.

    PubMed

    Galvez-Sola, L; Moral, R; Perez-Murcia, M D; Perez-Espinosa, A; Bustamante, M A; Martinez-Sabater, E; Paredes, C

    2010-02-15

    Composting is an environmentally friendly alternative for the recycling of organic wastes and its use is increasing in recent years. An exhaustive monitoring of the composting process and of the final compost characteristics is necessary to certify that the values of compost characteristics are within the limits established by the legislation in order to obtain a safe and marketable product. The analysis of these parameters on each composting batch in the commercial composting plant is time-consuming and expensive. So, their estimation in the composting facilities based on the use of near infrared reflectance spectroscopy (NIRS) could be an interesting approach in order to monitor compost quality. In this study, more than 300 samples from 20 different composting procedures were used to calibrate and validate the NIRS estimation of compost properties (pH, electrical conductivity (EC), total organic matter (TOM), total organic carbon (TOC), total nitrogen (TN) and C/N ratio, macronutrient contents (N, P, K) and potentially pollutant element concentrations (Fe, Cu, Mn and Zn)). The composts used were elaborated using different organic wastes from agroindustrial activities (GS: grape stalk; EGM: exhausted grape marc; GM: grape marc; V: vinasse; CJW: citrus juice waste; Alpeorujo: olive-oil waste; AS: almond skin; EP: exhausted peat; TSW: tomato soup waste; SMS: spent mushroom substrate) co-composted with manures (CM: cattle manure; PM: poultry manure) or urban wastes (SS: sewage sludge) The estimation results showed that the NIRS technique needs to be fitted to each element and property, using specific spectrum transformations, in order to achieve an acceptable accuracy in the prediction. However, excellent prediction results were obtained for TOM and TOC, successful calibrations for pH, EC, Fe and Mn, and moderately successful estimations for TN, C/N ratio, P, K, Cu and Zn. PMID:20061002

  4. Evaluation of various polyethylene as potential dosimeters by attenuated total reflectance-Fourier-transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Halperin, Fred; Collins, Greta; DiCicco, Michael; Logar, John

    2014-12-01

    Various types of polyethylene (PE) have been evaluated in the past for use as a potential dosimeter, chiefly via the formation of an unsaturated transvinylene (TV) double-bond resulting from exposure to ionizing radiation. The utilization of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy in characterizing TV formation in irradiated PE for a potential dosimeter has yet to be fully developed. In this initial investigation, various PE films/sheets were exposed to ionizing radiation in a high-energy 5 megaelectron volt (MeV) electron beam accelerator in the 10-500 kilogray (kGy) dose range, followed by ATR-FTIR analysis of TV peak formation at the 965 cm-1 wavenumber. There was an upward trend in TV formation for low-density polyethylene (LDPE) films and high-density polyethylene (HDPE) sheets as a function of absorbed dose in the 10-50 kGy dose range, however, the TV response could not be equated to a specific absorbed dose. LDPE film displayed a downward trend from 50 kGy to 250 kGy and then scattering up to 500 kGy; HDPE sheets demonstrated an upward trend in TV formation up to 500 kGy. For ultra-high molecular weight polyethylene (UHMWPE) sheets irradiated up to 150 kGy, TV response was equivalent to non-irradiated UHMWPE, and a minimal upward trend was observed for 200 kGy to 500 kGy. The scatter of the data for the irradiated PE films/sheets is such that the TV response could not be equated to a specific absorbed dose. A better correlation of the post-irradiation TV response to absorbed dose may be attained through a better understanding of variables.

  5. [Study on determining the content of all kinds of composition in the natural rock by near infrared reflectance spectroscopy].

    PubMed

    Li, Jun-Hua; Wu, Wei; He, Yan; Yao, Jin-Zhu; Wu, Xiao-Hong; Deng, Bo

    2013-01-01

    The infrared reflectance spectroscopy from the sample simulating natural-rock prepared by kaolin, muscovite and montmorillonite mixed-powders was obtained by a spectrometer. Spectral data preprocessing was done using SNV. Random forest mathematical modeling was used for predicting the components of rock samples. The smallest root mean square error of the predicted three types of rock composition were 0.088 0, 0.095 6 and 0.121 2 respectively. The predictive studies showed that the application of near infrared diffuse reflectance spectroscopy to determining the content of the natural rocks and minerals of various rock composition is feasible. The study provides a theoretical basis for the rapid detection of the rock composition in the future.

  6. Geographical differentiation of dried lentil seed (Lens culinaris) samples using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) and discriminant analysis.

    PubMed

    Kouvoutsakis, G; Mitsi, C; Tarantilis, P A; Polissiou, M G; Pappas, C S

    2014-02-15

    Diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) and discriminant analysis were used for the geographical differentiation of dried lentil seed (Lens culinaris) samples. Specifically, 18 Greek samples and nine samples imported from other countries were distinguished using the 2250-1720 and 1275-955 cm⁻¹ spectral regions. The differentiation is complete. The combination of DRIFTS and discriminant analysis enables simple, rapid, cheap and accurate differentiation of commercial lentil seeds in terms of geographical origin.

  7. Use of attenuated total reflectance Fourier transform infrared spectroscopy to identify microbial metabolic products on carbonate mineral surfaces.

    PubMed

    Bullen, Heather A; Oehrle, Stuart A; Bennett, Ariel F; Taylor, Nicholas M; Barton, Hazel A

    2008-07-01

    This paper demonstrates the use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to detect microbial metabolic products on carbonate mineral surfaces. By creating an ATR-FTIR spectral database for specific organic acids using ATR-FTIR spectroscopy we were able to distinguish metabolic acids on calcite surfaces following Escherichia coli growth. The production of these acids by E. coli was verified using high-performance liquid chromatography with refractive index detection. The development of this technique has allowed us to identify microbial metabolic products on carbonate surfaces in nutrient-limited cave environments.

  8. Use of Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy To Identify Microbial Metabolic Products on Carbonate Mineral Surfaces▿ †

    PubMed Central

    Bullen, Heather A.; Oehrle, Stuart A.; Bennett, Ariel F.; Taylor, Nicholas M.; Barton, Hazel A.

    2008-01-01

    This paper demonstrates the use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to detect microbial metabolic products on carbonate mineral surfaces. By creating an ATR-FTIR spectral database for specific organic acids using ATR-FTIR spectroscopy we were able to distinguish metabolic acids on calcite surfaces following Escherichia coli growth. The production of these acids by E. coli was verified using high-performance liquid chromatography with refractive index detection. The development of this technique has allowed us to identify microbial metabolic products on carbonate surfaces in nutrient-limited cave environments. PMID:18502924

  9. Atomic Scale Flatness of Chemically Cleaned Silicon Surfaces Studied by Infrared Attenuated-Total-Reflection Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sawara, Kenichi; Yasaka, Tatsuhiro; Miyazaki, Seiichi; Hirose, Masataka

    1992-07-01

    Hydrogen-terminated Si(111) and Si(100) surfaces obtained by aqueous HF or pH-modified (pH{=}5.3) buffered-HF (BHF) treatments have been characterized by a Fourier transform infrared (FT-IR) attenuated-total-reflection (ATR) technique. The BHF treatment provides better surface flatness than the HF treatment. Pure water rinse is effective for improving the Si(111) surface flatness, while this is not the case for Si(100) because the pure water acts as an alkaline etchant and promotes the formation of (111) microfacets or microdefects on the (100) surface.

  10. Fully reflective deep ultraviolet to near infrared spectrometer and entrance optics for resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Schulz, B.; Bäckström, J.; Budelmann, D.; Maeser, R.; Rübhausen, M.; Klein, M. V.; Schoeffel, E.; Mihill, A.; Yoon, S.

    2005-07-01

    We present the design and performance of a new triple-grating deep ultraviolet to near-infrared spectrometer. The system is fully achromatic due to the use of reflective optics. The minimization of image aberrations by using on- and off- axis parabolic mirrors as well as elliptical mirrors yields a strong stray light rejection with high resolution over a wavelength range between 165 and 1000nm. The Raman signal is collected with a reflective entrance objective with a numerical aperture of 0.5, featuring a Cassegrain-type design. Resonance Raman studies on semiconductors and on correlated compounds, such as LaMnO3, highlight the performance of this instrument, and show diverse resonance effects between 1.96 and 5.4eV.

  11. Combination of infrared thermography and reflectance spectroscopy for precise classification of hair follicle stage

    NASA Astrophysics Data System (ADS)

    Wang, Jianru; Guan, Yue; Liu, Caihua; Zhu, Dan

    2015-03-01

    Hair follicles enjoy continual cycle of anagen, catagen and telogen all life. They not only provide a unique opportunity to study the physiological mechanism of organ regeneration, but also benefit to guide the treatment of organ repair in regenerative medicine. Usually, the histological examination as a gold standard has been applied to determine the stage of hair follicle cycle, but noninvasive classification of hair cycle in vivo remains unsolved. In this study, the thermal infrared imager was applied to measure the temperature change of mouse dorsal skin with hair follicle cycle, and the change of diffuse reflectance was monitored by the optical fiber spectrometer. Histological examination was used to verify the hair follicle stages. The results indicated that the skin temperature increased at the beginning of anagen. After having stayed a high value for several days, the temperature began to decrease. At the same time, the skin diffuse reflectance decreased until the end of this period. Then the temperature increased gradually after slightly decreased when the hair follicle entered into catagen stage, and the diffuse reflectance increased at this time. In telogen, both the temperature and the diffuse reflectance went back to a steady state all the time. Sub-stages of hair follicle cycle could be distinguished based on the joint curves. This study provided a new method to noninvasively recognize the hair follicle stage, and should be valuable for the basic and therapeutic investigations on hair regeneration.

  12. Visible and near-infrared reflectance spectroscopy of planetary analog materials. Experimental facility at Laboratoire de Planetologie de Grenoble.

    NASA Astrophysics Data System (ADS)

    Pommerol, A.; Brissaud, O.; Schmitt, B.; Quirico, E.; Doute, S.

    2007-08-01

    We have developed an original experimental facility designed to measure the bidirectional reflectance spectra of planetary analog materials. These measurements are helpful to interpret the observations of the spectrometers on board space probes in orbit around various Solar System bodies. The central part of the facility is the LPG spectrogonio- radiometer (Brissaud et al., 2004). This instrument provides measurements of samples BRDF (Bidirectional Reflectance Distribution Function) with high photometric and spectrometric accuracy in the spectral range of visible and near-infrared (0.3 - 4.8 microns). Measurements can be made at any value of incidence and emergence angle up to 80°. Azimuth angle is allowed to vary between 0 and 180°. The instrument was recently installed in a cold room allowing ambient temperatures as low as -20°C. This makes possible the measurements on different kinds of water ice samples (slab ice, frost, snow...) and mixtures of minerals and water ice with unprecedented accuracy. We also have designed and built a simulation chamber to measure spectra of samples (water ice and/or minerals) under an atmosphere with perfectly controlled temperature, pressure and composition. The main objective of this last improvement is the study of water exchange between planetary regolith analogs and atmosphere (adsorption/ desorption, condensation/sublimation). Experimental results will mainly apply to Martian water cycle and hydrated mineralogy. This simulation chamber also provides an efficient way to obtain bidirectional reflectance spectra of dry materials (removal of adsorbed water) with implications for planetary bodies without atmospheric or surface water (Titan, asteroids...). The reflectance spectroscopy facility is part of a large panel of instruments and techniques available at Laboratoire de Planetologie de Grenoble that provide complementary measurements on the same samples: infrared transmission spectroscopy of thin ice films, thick liquid and

  13. Prediction of leaf chemistry by the use of visible and near infrared reflectance spectroscopy

    NASA Technical Reports Server (NTRS)

    Card, Don H.; Peterson, David L.; Matson, Pamela A.; Aber, John D.

    1988-01-01

    The chemical content of dry, ground leaf material sampled from deciduous and conifer tree species from sites in Alaska, Wisconsin, and California was estimated using visible and shortwave IR spectroscopy. Seven chemical components - sugar, starch, protein, cellulose, total chlorophyll, lignin, and total nitrogen - were analyzed by wet chemical methods and their concentrations regressed against log 1/rho and first and second differences of log 1/rho (where rho is measured reflectance) at wavelengths selected by stepwise regression. Predictions of chemical concentrations based on cross validation suggest that this technique may be useful for extracting vegetation canopy biochemical information by remote sensing.

  14. Hollow optical-fiber based infrared spectroscopy for measurement of blood glucose level by using multi-reflection prism.

    PubMed

    Kino, Saiko; Omori, Suguru; Katagiri, Takashi; Matsuura, Yuji

    2016-02-01

    A mid-infrared attenuated total reflection (ATR) spectroscopy system employing hollow optical fibers and a trapezoidal multi-reflection ATR prism has been developed to measure blood glucose levels. Using a multi-reflection prism brought about higher sensitivity, and the flat and wide contact surface of the prism resulted in higher measurement reproducibility. An analysis of in vivo measurements of human inner lip mucosa revealed clear signatures of glucose in the difference spectra between ones taken during the fasting state and ones taken after ingestion of glucose solutions. A calibration plot based on the absorption peak at 1155 cm(-1) that originates from the pyranose ring structure of glucose gave measurement errors less than 20%.

  15. Hollow optical-fiber based infrared spectroscopy for measurement of blood glucose level by using multi-reflection prism

    PubMed Central

    Kino, Saiko; Omori, Suguru; Katagiri, Takashi; Matsuura, Yuji

    2016-01-01

    A mid-infrared attenuated total reflection (ATR) spectroscopy system employing hollow optical fibers and a trapezoidal multi-reflection ATR prism has been developed to measure blood glucose levels. Using a multi-reflection prism brought about higher sensitivity, and the flat and wide contact surface of the prism resulted in higher measurement reproducibility. An analysis of in vivo measurements of human inner lip mucosa revealed clear signatures of glucose in the difference spectra between ones taken during the fasting state and ones taken after ingestion of glucose solutions. A calibration plot based on the absorption peak at 1155 cm−1 that originates from the pyranose ring structure of glucose gave measurement errors less than 20%. PMID:26977373

  16. Hollow optical-fiber based infrared spectroscopy for measurement of blood glucose level by using multi-reflection prism.

    PubMed

    Kino, Saiko; Omori, Suguru; Katagiri, Takashi; Matsuura, Yuji

    2016-02-01

    A mid-infrared attenuated total reflection (ATR) spectroscopy system employing hollow optical fibers and a trapezoidal multi-reflection ATR prism has been developed to measure blood glucose levels. Using a multi-reflection prism brought about higher sensitivity, and the flat and wide contact surface of the prism resulted in higher measurement reproducibility. An analysis of in vivo measurements of human inner lip mucosa revealed clear signatures of glucose in the difference spectra between ones taken during the fasting state and ones taken after ingestion of glucose solutions. A calibration plot based on the absorption peak at 1155 cm(-1) that originates from the pyranose ring structure of glucose gave measurement errors less than 20%. PMID:26977373

  17. An investigation of the desorption of hydrogen from lithium oxide using temperature programmed desorption and diffuse reflectance infrared spectroscopy

    SciTech Connect

    Kopasz, J.P.; Johnson, C.E.; Ortiz-Villafuerte, J.

    1994-09-01

    The addition of hydrogen to the purge stream has been shown to enhance tritium release from ceramic breeder materials. In an attempt to determine the mechanism for this enhancement the authors have investigated the adsorption and desorption of hydrogen and water from lithium oxide (a leading candidate for the breeder material) by temperature programmed desorption and diffuse reflectance infrared spectroscopy. The results from these studies indicate that several different types of hydroxide groups are formed on the lithium oxide surface. They also suggest that under certain conditions hydride species form on the surface. The role of these species in tritium release from lithium oxide is discussed.

  18. Resin characterization in cured graphite fiber reinforced composites using diffuse reflectance-FTIR. [Fourier transform infrared spectroscopy

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Stein, B. A.; Chang, A. C.

    1983-01-01

    The feasibility of using diffuse reflectance in combination with Fourier transform infrared spectroscopy to obtain information on cured graphite fiber reinforced polymeric matrix resin composites was investigated. Several graphite/epoxy, polysulfone, and polyimide composites exposed to thermal or radiation environments were examined. An experimental polyimide-sulfone adhesive tape was also studied during processing. In each case, significant changes in resin molecular structure was observed due to environmental exposure. These changes in molecular structure were correlated with previously observed changes in material properties providing new insights into material behavior.

  19. Low-temperature and low atmospheric pressure infrared reflectance spectroscopy of Mars soil analog materials

    NASA Technical Reports Server (NTRS)

    Bishop, Janice L.; Pieters, Carle M.

    1995-01-01

    Infrared reflectance spectra of carefully selected Mars soil analog materials have been measured under low atmospheric pressures and temperatures. Chemically altered montmorillonites containing ferrihydrite and hydrated ferric sulfate complexes are examined, as well as synthetic ferrihydrite and a palagonitic soil from Haleakala, Maui. Reflectance spectra of these analog materials exhibit subtle visible to near-infrared features, which are indicative of nanophase ferric oxides or oxyhydroxides and are similar to features observed in the spectra of the bright regions of Mars. Infrared reflectance spectra of these analogs include hydration features due to structural OH, bound H2O, and adsorbed H2O. The spectral character of these hydration features is highly dependent on the sample environment and on the nature of the H2O/OH in the analogs. The behavior of the hydration features near 1.9 micron, 2.2 micron, 2.7 micron, 3 micron, and 6 microns are reported here in spectra measured under a Marslike atmospheric environment. In spectra of these analogs measured under dry Earth atmospheric conditions the 1.9-micron band depth is 8-17%; this band is much stronger under moist conditions. Under Marslike atmospheric conditions the 1.9-micron feature is broad and barely discernible (1-3% band depth) in spectra of the ferrihydrite and palagonitic soil samples. In comparable spectra of the ferric sulfate-bearing montmorillonite the 1.9-micron feature is also broad, but stronger (6% band depth). In the low atmospheric pressure and temperature spectra of the ferrihydrite-bearing montmorillonite this feature is sharper than the other analogs and relatively stronger (6% band depth). Although the intensity of the 3-micron band is weaker in spectra of each of the analogs when measured under Marslike conditions, the 3-micron band remains a dominant feature and is especially broad in spectra of the ferrihydrite and palagonitic soil. The structural OH features observed in these materials

  20. Low-temperature and low atmospheric pressure infrared reflectance spectroscopy of Mars soil analog materials

    NASA Technical Reports Server (NTRS)

    Bishop, Janice L.; Pieters, Carle M.

    1995-01-01

    Infrared reflectance spectra of carefully selected Mars soil analog materials have been measured under low atmospheric pressures and temperatures. Chemically altered montmorillonites containing ferrihydrite and hydrated ferric sulfate complexes are examined, as well as synthetic ferrihydrate and a palagonitic soil from Haleakala, Maui. Reflectance spectra of these analog materials exhibit subtle visible to near-infrared features, which are indicative of nanophase ferric oxides or oxyhydroxides and are similar to features observed in the spectra of the bright regions of Mars. Infrared reflectance spectra of these analogs include hydration features due to structural OH, bound H2O and adsorbed H2O. The spectal character of these hydration features is highly dependent on the sample environment and on the nature of the H2O/OH in the analogs. The behavior of the hydration features near 1.9 micrometers, 2.2 micrometers, 2.7 micrometers, 3 micrometers, and 6 micrometers are reported here in spetra measured under Marslike atmospheric environment. In spectra of these analogs measured under dry Earth atmospheric conditions the 1.9-micrometer band depth is 8-17%; this band is much stonger under moist conditions. Under Marslike atmospheric conditions the 1.9-micrometer feature is broad and barely discernible (1-3% band depth) in spectra of the ferrihydrite and palagonitic soil samples. In comparable spectra of the ferric sulfate-bearing montmorillonite the 1.9-micrometer feature is also broad, but stronger (6% band depth). In the low atmospheric pressure and temperature spectra of the ferrihydrite-bearing montmorillonite this feature is sharper than the other analogs and relatively stronger (6% band depth). Although the intensity of the 3- micrometer band is weaker in spectra of each of the analogs when measured under Marslike conditions, the 3-micromter band remains a dominant feature and is especially broad in spectra of the ferrihydrite and palagonitic soil. The structural

  1. Multiple perturbation two-dimensional correlation analysis of cellulose by attenuated total reflection infrared spectroscopy.

    PubMed

    Shinzawa, Hideyuki; Morita, Shin-Ich; Awa, Kimie; Okada, Mariko; Noda, Isao; Ozaki, Yukihiro; Sato, Hidetoshi

    2009-05-01

    An extension of the two-dimensional (2D) correlation analysis scheme for multi-dimensional perturbation is described. A simple computational form is provided to construct synchronous correlation and disrelation maps for the analysis of microscopic imaging data based on two independent perturbation variables. Sets of time-dependent attenuated total reflection infrared (ATR-IR) spectra of water and cellulose mixtures were collected during the evaporation of water from finely ground cellulose. The system exhibits complex behaviors in response to two independent perturbations, i.e., evaporation time and grinding time. Multiple perturbation 2D analysis reveals a specific difference in the rate of evaporation of water molecules when accompanied by crystallinity changes of cellulose. It identifies subtle differences in the volatility of water, which is related to the crystalline structure of cellulose. PMID:19470205

  2. Low temperature hydrogen plasma-assisted atomic layer deposition of copper studied using in situ infrared reflection absorption spectroscopy

    SciTech Connect

    Chaukulkar, Rohan P.; Rai, Vikrant R.; Agarwal, Sumit; Thissen, Nick F. W.

    2014-01-15

    Atomic layer deposition (ALD) is an ideal technique to deposit ultrathin, conformal, and continuous metal thin films. However, compared to the ALD of binary materials such as metal oxides and metal nitrides, the surface reaction mechanisms during metal ALD are not well understood. In this study, the authors have designed and implemented an in situ reflection-absorption infrared spectroscopy (IRAS) setup to study the surface reactions during the ALD of Cu on Al{sub 2}O{sub 3} using Cu hexafluoroacetylacetonate [Cu(hfac){sub 2}] and a remote H{sub 2} plasma. Our infrared data show that complete ligand-exchange reactions occur at a substrate temperature of 80 °C in the absence of surface hydroxyl groups. Based on infrared data and previous studies, the authors propose that Cu(hfac){sub 2} dissociatively chemisorbs on the Al{sub 2}O{sub 3} surface, where the Al-O-Al bridge acts as the surface reactive site, leading to surface O-Cu-hfac and O-Al-hfac species. Surface saturation during the Cu(hfac){sub 2} half-cycle occurs through blocking of the available chemisorption sites. In the next half-reaction cycle, H radicals from an H{sub 2} plasma completely remove these surface hfac ligands. Through this study, the authors have demonstrated the capability of in situ IRAS as a tool to study surface reactions during ALD of metals. While transmission and internal reflection infrared spectroscopy are limited to the first few ALD cycles, IRAS can be used to probe all stages of metal ALD starting from initial nucleation to the formation of a continuous film.

  3. Attenuated Total Reflection Mid-Infrared (ATR-MIR) Spectroscopy and Chemometrics for the Identification and Classification of Commercial Tannins.

    PubMed

    Ricci, Arianna; Parpinello, Giuseppina P; Olejar, Kenneth J; Kilmartin, Paul A; Versari, Andrea

    2015-11-01

    Attenuated total reflection Fourier transform infrared (FT-IR) spectroscopy was used to characterize 40 commercial tannins, including condensed and hydrolyzable chemical classes, provided as powder extracts from suppliers. Spectral data were processed to detect typical molecular vibrations of tannins bearing different chemical groups and of varying botanical origin (univariate qualitative analysis). The mid-infrared region between 4000 and 520 cm(-1) was analyzed, with a particular emphasis on the vibrational modes in the fingerprint region (1800-520 cm(-1)), which provide detailed information about skeletal structures and specific substituents. The region 1800-1500 cm(-1) contained signals due to hydrolyzable structures, while bands due to condensed tannins appeared at 1300-900 cm(-1) and exhibited specific hydroxylation patterns useful to elucidate the structure of the flavonoid monomeric units. The spectra were investigated further using principal component analysis for discriminative purposes, to enhance the ability of infrared spectroscopy in the classification and quality control of commercial dried extracts and to enhance their industrial exploitation.

  4. Use of attenuated total reflection-Fourier transform infrared spectroscopy to measure collagen degradation in historical parchments.

    PubMed

    Gonzalez, Lee; Wess, Tim

    2008-10-01

    Developing a noninvasive method to assess the degraded state of historical parchments is essential to providing the best possible care for these documents. The conformational changes observed when collagen molecules, the primary constituent of parchment, unfold have been analyzed using attenuated total reflection-Fourier transform infrared (ATR-FT-IR) spectroscopy and the nanoscopic structural changes have been analyzed using X-ray diffraction (XRD). The relationship between the results obtained from these techniques was studied using principal component analysis, where correlation was found. The extent of gelatinization of historical parchments has been assessed using ATR-FT-IR and XRD and the frequency shifts observed as collagen degrades into gelatin have been reported. These results indicate that collagen degradation can be measured noninvasively in parchment and demonstrate the utility of ATR-FT-IR spectroscopy as a method to investigate historical documents.

  5. Reflectance Infrared Spectroscopy on Operating Surface Acoustic Wave Chemical Sensors During Exposure to Gas-Phase Analytes

    SciTech Connect

    Hierlemann, A.; Hill, M.; Ricco, A.J.; Staton, A.W.; Thomas, R.C.

    1999-01-11

    We have developed instrumentation to enable the combination of surface acoustic wave (SAW) sensor measurements with direct, in-situ molecular spectroscopic measurements to understand the response of the SAW sensors with respect to the interfacial chemistry of surface-confined sensing films interacting with gas-phase analytes. Specifically, the instrumentation and software was developed to perform in-situ Fourier-transform infrared external-reflectance spectroscopy (FTIR-ERS) on operating SAW devices during dosing of their chemically modified surfaces with analytes. By probing the surface with IR spectroscopy during gas exposure, it is possible to understand in unprecedented detail the interaction processes between the sorptive SAW coatings and the gaseous analyte molecules. In this report, we provide details of this measurement system, and also demonstrate the utility of these combined measurements by characterizing the SAW and FTIR-ERS responses of organic thin-film sensor coatings interacting with gas-phase analytes.

  6. Determination of copper and zinc pollutants in Ludwigia prostrata Roxb using near-infrared reflectance spectroscopy (NIRS).

    PubMed

    Ouyang, Aiguo; Jiang, Lixia; Liu, Yande; Jiang, Lihong; Hao, Yong; He, Bingbing

    2015-03-01

    The feasibility of using near-infrared reflectance spectroscopy (NIRS) to determine the concentrations of copper (Cu) and zinc (Zn) in Ludwigia prostrata Roxb plants was investigated. Ludwigia prostrata Roxb plants were grown over a full growth cycle under controlled laboratory conditions in soils contaminated with heavy metals. The Cu and Zn concentrations in 72 L. prostrata Roxb samples were analyzed using flame atomic absorption spectrometry, and NIRS spectra were collected in the 1099-2500 nm range. Five mathematical treatments of the spectral data were compared prior to developing the calibration models (n = 48) using partial least squares regression methods. The two calibration models for Cu and Zn concentrations were evaluated according to the correlation coefficient of cross-validation (R(cv)) and root mean squares error of cross-validation. The highest R(cv) and the lowest RMSECV were obtained for Cu (0.9 and 7.24 mg kg(-1)) and Zn (0.94 and 19.17 mg kg(-1)), respectively. The results showed that near-infrared diffuse reflectance spectroscopy can be used for the rapid determination of Cu and Zn in leaves of L. prostrata Roxb plants.

  7. Early detection of melanoma with the combined use of acoustic microscopy, infrared reflectance and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Karagiannis, Georgios T.; Grivas, Ioannis; Tsingotjidou, Anastasia; Apostolidis, Georgios K.; Grigoriadou, Ifigeneia; Dori, I.; Poulatsidou, Kyriaki-Nefeli; Doumas, Argyrios; Wesarg, Stefan; Georgoulias, Panagiotis

    2015-03-01

    Malignant melanoma is a form of skin cancer, with increasing incidence worldwide. Early diagnosis is crucial for the prognosis and treatment of the disease. The objective of this study is to develop a novel animal model of melanoma and apply a combination of the non-invasive imaging techniques acoustic microscopy, infrared (IR) and Raman spectroscopies, for the detection of developing tumors. Acoustic microscopy provides information about the 3D structure of the tumor, whereas, both spectroscopic modalities give qualitative insight of biochemical changes during melanoma development. In order to efficiently set up the final devices, propagation of ultrasonic and electromagnetic waves in normal skin and melanoma simulated structures was performed. Synthetic and grape-extracted melanin (simulated tumors), endermally injected, were scanned and compared to normal skin. For both cases acoustic microscopy with central operating frequencies of 110MHz and 175MHz were used, resulting to the tomographic imaging of the simulated tumor, while with the spectroscopic modalities IR and Raman differences among spectra of normal and melanin- injected sites were identified in skin depth. Subsequently, growth of actual tumors in an animal melanoma model, with the use of human malignant melanoma cells was achieved. Acoustic microscopy and IR and Raman spectroscopies were also applied. The development of tumors at different time points was displayed using acoustic microscopy. Moreover, the changes of the IR and Raman spectra were studied between the melanoma tumors and adjacent healthy skin. The most significant changes between healthy skin and the melanoma area were observed in the range of 900-1800cm-1 and 350-2000cm-1, respectively.

  8. Usefulness of near-infrared reflectance (NIR) spectroscopy and chemometrics to discriminate fishmeal batches made with different fish species.

    PubMed

    Cozzolino, Daniel; Chree, A; Scaife, J R; Murray, Ian

    2005-06-01

    Near-infrared reflectance (NIR) spectroscopy combined with chemometrics was used to identify and authenticate fishmeal batches made with different fish species. Samples from a commercial fishmeal factory (n = 60) were scanned in the NIR region (1100-2500 nm) in a monochromator instrument in reflectance. Principal component analysis (PCA), dummy partial least-squares regression (DPLS), and linear discriminant analysis (LDA) based on PCA scores were used to identify the origin of fishmeal produced using different fish species. Cross-validation was used as validation method when classification models were developed. DPLS correctly classified 80 and 82% of the fishmeal samples. LDA calibration models correctly classified >80% of fishmeal samples according to fish species The results demonstrated the usefulness of NIR spectra combined with chemometrics as an objective and rapid method for the authentication and identification of fish species used to manufacture the fishmeal.

  9. Membrane molecule reorientation in an electric field recorded by attenuated total reflection Fourier-transform infrared spectroscopy.

    PubMed

    Le Saux, A; Ruysschaert, J M; Goormaghtigh, E

    2001-01-01

    Electric fields play an important role in the physiological function of macromolecules. Much is known about the role that electric fields play in biological systems, but membrane molecule structure and orientation induced by electric fields remain essentially unknown. In this paper, we present a polarized attenuated total reflection (ATR) experiment we designed to study the effect of electric fields on membrane molecule structure and orientation by Fourier-transform infrared (FTIR) spectroscopy. Two germanium crystals used as the internal reflection element for ATR-FTIR experiments were coated with a thin layer of polystyrene as insulator and used as electrodes to apply an electric field on an oriented stack of membranes made of dioleylphosphatidylcholine (DOPC) and melittin. This experimental set up allowed us for the first time to show fully reversible orientational changes in the lipid headgroups specifically induced by the electric potential difference.

  10. Membrane molecule reorientation in an electric field recorded by attenuated total reflection Fourier-transform infrared spectroscopy.

    PubMed Central

    Le Saux, A; Ruysschaert, J M; Goormaghtigh, E

    2001-01-01

    Electric fields play an important role in the physiological function of macromolecules. Much is known about the role that electric fields play in biological systems, but membrane molecule structure and orientation induced by electric fields remain essentially unknown. In this paper, we present a polarized attenuated total reflection (ATR) experiment we designed to study the effect of electric fields on membrane molecule structure and orientation by Fourier-transform infrared (FTIR) spectroscopy. Two germanium crystals used as the internal reflection element for ATR-FTIR experiments were coated with a thin layer of polystyrene as insulator and used as electrodes to apply an electric field on an oriented stack of membranes made of dioleylphosphatidylcholine (DOPC) and melittin. This experimental set up allowed us for the first time to show fully reversible orientational changes in the lipid headgroups specifically induced by the electric potential difference. PMID:11159405

  11. [Rapid quantitative analysis of hydrocarbon composition of furfural extract oils using attenuated total reflection infrared spectroscopy].

    PubMed

    Li, Na; Yuan, Hong-Fu; Hu, Ai-Qin; Liu, Wei; Song, Chun-Feng; Li, Xiao-Yu; Song, Yi-Chang; He, Qi-Jun; Liu, Sha; Xu, Xiao-Xuan

    2014-07-01

    A set of rapid analysis system for hydrocarbon composition of heavy oils was designed using attenuated total reflection FTIR spectrometer and chemometrics to determine the hydrocarbon composition of furfural extract oils. Sixty two extract oil samples were collected and their saturates and aromatics content data were determined according to the standard NB/SH/T0509-2010, then the total contents of resins plus asphaltenes were calculated by the subtraction method in the percentage of weight. Based on the partial least squares (PLS), calibration models for saturates, aromatics, and resin+asphaltene contents were established using attenuated total reflection FTIR spectroscopy, with their SEC, 1.43%, 0.91% and 1.61%, SEP, 1.56%, 1.24% and 1.81%, respectively, meeting the accuracy and repeatability required for the standard. Compared to the present standard method, the efficiency of hydrocarbon composition analysis for furfural extract oils is significantly improved by the new method which is rapid and simple. The system could also be used for other heavy oil analysis, with excellent extension and application foreground.

  12. Characterizing and Authenticating Montilla-Moriles PDO Vinegars Using Near Infrared Reflectance Spectroscopy (NIRS) Technology

    PubMed Central

    De la Haba, María-José; Arias, Mar; Ramírez, Pilar; López, María-Isabel; Sánchez, María-Teresa

    2014-01-01

    This study assessed the potential of near infrared (NIR) spectroscopy as a non-destructive method for characterizing Protected Designation of Origin (PDO) “Vinagres de Montilla-Moriles” wine vinegars and for classifying them as a function of the manufacturing process used. Three spectrophotometers were evaluated for this purpose: two monochromator instruments (Foss NIRSystems 6500 SY-I and Foss NIRSystems 6500 SY-II; spectral range 400–2,500 nm in both cases) and a diode-array instrument (Corona 45 VIS/NIR; spectral range 380–1,700 nm). A total of 70 samples were used to predict major chemical quality parameters (total acidity, fixed acidity, volatile acidity, pH, dry extract, ash, acetoin, methanol, total polyphenols, color (tonality and intensity), and alcohol content), and to construct models for the classification of vinegars as a function of the manufacturing method used. The results obtained indicate that this non-invasive technology can be used successfully by the vinegar industry and by PDO regulators for the routine analysis of vinegars in order to authenticate them and to detect potential fraud. Slightly better results were achieved with the two monochromator instruments. The findings also highlight the potential of these NIR instruments for predicting the manufacturing process used, this being of particular value for the industrial authentication of traditional wine vinegars. PMID:24561402

  13. Characterizing and authenticating Montilla-Moriles PDO vinegars using near infrared reflectance spectroscopy (NIRS) technology.

    PubMed

    De la Haba, María-José; Arias, Mar; Ramírez, Pilar; López, María-Isabel; Sánchez, María-Teresa

    2014-02-20

    This study assessed the potential of near infrared (NIR) spectroscopy as a non-destructive method for characterizing Protected Designation of Origin (PDO) "Vinagres de Montilla-Moriles" wine vinegars and for classifying them as a function of the manufacturing process used. Three spectrophotometers were evaluated for this purpose: two monochromator instruments (Foss NIRSystems 6500 SY-I and Foss NIRSystems 6500 SY-II; spectral range 400-2,500 nm in both cases) and a diode-array instrument (Corona 45 VIS/NIR; spectral range 380-1,700 nm). A total of 70 samples were used to predict major chemical quality parameters (total acidity, fixed acidity, volatile acidity, pH, dry extract, ash, acetoin, methanol, total polyphenols, color (tonality and intensity), and alcohol content), and to construct models for the classification of vinegars as a function of the manufacturing method used. The results obtained indicate that this non-invasive technology can be used successfully by the vinegar industry and by PDO regulators for the routine analysis of vinegars in order to authenticate them and to detect potential fraud. Slightly better results were achieved with the two monochromator instruments. The findings also highlight the potential of these NIR instruments for predicting the manufacturing process used, this being of particular value for the industrial authentication of traditional wine vinegars.

  14. Mid-infrared bi-directional reflectance spectroscopy of impact melt glasses and tektites

    NASA Astrophysics Data System (ADS)

    Morlok, Andreas; Stojic, Aleksandra; Weber, Iris; Hiesinger, Harald; Zanetti, Michael; Helbert, Joern

    2016-11-01

    We have analyzed 14 impact melt glass samples, covering the compositional range from highly felsic to mafic/basaltic, as part of our effort to provide mid-infrared spectra (7-14 μm) for MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer), an instrument onboard of the ESA/JAXA BepiColombo mission. Since Mercury was exposed to many impacts in its history, and impact glasses are also common on other bodies, powders of tektites (Irghizite, Libyan Desert Glass, Moldavite, Muong Nong, Thailandite) and impact glasses (from the Dellen, El'gygytgyn, Lonar, Mien, Mistastin, and Popigai impact structures) were analyzed in four size fractions of (0-25, 25-63, 93-125 and 125-250 μm) from 2.5 to 19 μm in bi-directional reflectance. The characteristic Christiansen Feature (CF) is identified between 7.3 μm (Libyan Desert Glass) and 8.2 μm (Dellen). Most samples show mid-infrared spectra typical of highly amorphous material, dominated by a strong Reststrahlen Band (RB) between 8.9 μm (Libyan Desert Glass) and 10.3 μm (Dellen). Even substantial amounts of mineral fragments hardly affect this general band shape. Comparisons of the SiO2 content representing the felsic/mafic composition of the samples with the CF shows felsic/intermediate glass and tektites forming a big group, and comparatively mafic samples a second one. An additional sign of a highly amorphous state is the lack of features at wavelengths longer than ∼15 μm. The tektites and two impact glasses, Irghizite and El'gygytgyn respectively, have much weaker water features than most of the other impact glasses. For the application in remote sensing, spectral features have to be correlated with compositional characteristics of the materials. The dominating RB in the 7-14 μm range correlates well with the SiO2 content, the Christiansen Feature shows similar dependencies. To distinguish between glass and crystalline phases of the same chemical composition, a comparison between CF the SCFM index (SiO2/(SiO2

  15. Mapping of egg yolk and animal skin glue paint binders in Early Renaissance paintings using near infrared reflectance imaging spectroscopy.

    PubMed

    Dooley, Kathryn A; Lomax, Suzanne; Zeibel, Jason G; Miliani, Costanza; Ricciardi, Paola; Hoenigswald, Ann; Loew, Murray; Delaney, John K

    2013-09-01

    In situ chemical imaging techniques are being developed to provide information on the spatial distribution of artists' pigments used in polychrome works of art such as paintings. The new methods include reflectance imaging spectroscopy and X-ray fluorescence mapping. Results from these new methods have extended the knowledge obtained from site-specific chemical analyses widely in use. While these mapping methods have aided in determining the distribution of pigments, there is a growing interest to develop methods capable of identifying and mapping organic paint binders as well. Near infrared (NIR) reflectance spectroscopy has been extensively used in the remote sensing field as well as in the chemical industry to detect organic compounds. NIR spectroscopy provides a rapid method to assay organics by utilizing vibrational overtones and combination bands of fundamental absorptions that occur in the mid-IR. Here we explore the utility of NIR reflectance imaging spectroscopy to map organic binders in situ by examining a series of panel paintings known to have been painted using distemper (animal skin glue) and tempera (egg yolk) binders as determined by amino acid analysis of samples taken from multiple sites on the panels. In this report we demonstrate the success in identifying and mapping these binders by NIR reflectance imaging spectroscopy in situ. Three of the four panel paintings from Cosimo Tura's The Annunciation with Saint Francis and Saint Louis of Toulouse (ca. 1475) are imaged using a highly sensitive, line-scanning hyperspectral imaging camera. The results show an animal skin glue binder was used for the blue skies and blue robe of the Virgin Mary, and egg yolk tempera was used for the red robes and brown landscape. The mapping results show evidence for the use of both egg yolk and animal skin glue in the faces of the figures. The strongest absorption associated with lipidic egg yolk features visually correlates with areas that appear to have white

  16. Exploration of attenuated total reflectance mid-infrared spectroscopy and multivariate calibration to measure immunoglobulin G in human sera.

    PubMed

    Hou, Siyuan; Riley, Christopher B; Mitchell, Cynthia A; Shaw, R Anthony; Bryanton, Janet; Bigsby, Kathryn; McClure, J Trenton

    2015-09-01

    Immunoglobulin G (IgG) is crucial for the protection of the host from invasive pathogens. Due to its importance for human health, tools that enable the monitoring of IgG levels are highly desired. Consequently there is a need for methods to determine the IgG concentration that are simple, rapid, and inexpensive. This work explored the potential of attenuated total reflectance (ATR) infrared spectroscopy as a method to determine IgG concentrations in human serum samples. Venous blood samples were collected from adults and children, and from the umbilical cord of newborns. The serum was harvested and tested using ATR infrared spectroscopy. Partial least squares (PLS) regression provided the basis to develop the new analytical methods. Three PLS calibrations were determined: one for the combined set of the venous and umbilical cord serum samples, the second for only the umbilical cord samples, and the third for only the venous samples. The number of PLS factors was chosen by critical evaluation of Monte Carlo-based cross validation results. The predictive performance for each PLS calibration was evaluated using the Pearson correlation coefficient, scatter plot and Bland-Altman plot, and percent deviations for independent prediction sets. The repeatability was evaluated by standard deviation and relative standard deviation. The results showed that ATR infrared spectroscopy is potentially a simple, quick, and inexpensive method to measure IgG concentrations in human serum samples. The results also showed that it is possible to build a united calibration curve for the umbilical cord and the venous samples.

  17. Rapid detection of kernel rots and mycotoxins in maize by near-infrared reflectance spectroscopy.

    PubMed

    Berardo, Nicola; Pisacane, Vincenza; Battilani, Paola; Scandolara, Andrea; Pietri, Amedeo; Marocco, Adriano

    2005-10-19

    Near-infrared (NIR) spectroscopy is a practical spectroscopic procedure for the detection of organic compounds in matter. It is particularly useful because of its nondestructiveness, accuracy, rapid response, and easy operation. This work assesses the applicability of NIR for the rapid identification of micotoxigenic fungi and their toxic metabolites produced in naturally and artificially contaminated products. Two hundred and eighty maize samples were collected both from naturally contaminated maize crops grown in 16 areas in north-central Italy and from ears artificially inoculated with Fusarium verticillioides. All samples were analyzed for fungi infection, ergosterol, and fumonisin B1 content. The results obtained indicated that NIR could accurately predict the incidence of kernels infected by fungi, and by F. verticillioides in particular, as well as the quantity of ergosterol and fumonisin B1 in the meal. The statistics of the calibration and of the cross-validation for mold infection and for ergosterol and fumonisin B1 contents were significant. The best predictive ability for the percentage of global fungal infection and F. verticillioides was obtained using a calibration model utilizing maize kernels (r2 = 0.75 and SECV = 7.43) and maize meals (r2 = 0.79 and SECV = 10.95), respectively. This predictive performance was confirmed by the scatter plot of measured F. verticillioides infection versus NIR-predicted values in maize kernel samples (r2 = 0.80). The NIR methodology can be applied for monitoring mold contamination in postharvest maize, in particular F. verticilliodes and fumonisin presence, to distinguish contaminated lots from clean ones, and to avoid cross-contamination with other material during storage and may become a powerful tool for monitoring the safety of the food supply.

  18. Diffuse near-infrared reflectance spectroscopy during heatstroke in a mouse model: pilot study

    NASA Astrophysics Data System (ADS)

    Abookasis, David; Zafrir, Elad; Nesher, Elimelech; Pinhasov, Albert; Sternklar, Shmuel; Mathews, Marlon S.

    2012-10-01

    Heatstroke, a form of hyperthermia, is a life-threatening condition characterized by an elevated core body temperature that rises above 40°C (104°F) and central nervous system dysfunction that results in delirium, convulsions, or coma. Without emergency treatment, the victim lapses into a coma and death soon follows. The study presented was conducted with a diffuse reflectance spectroscopy (DRS) setup to assess the effects of brain dysfunction that occurred during heatstroke in mice model (n=6). It was hypothesized that DRS can be utilized in small animal studies to monitor change in internal brain tissue temperature during heatstroke injury since it induces a sequence of pathologic changes that change the tissue composition and structure. Heatstroke was induced by exposure of the mice body under general anesthesia, to a high ambient temperature. A type of DRS in which the brain tissue was illuminated through the intact scalp with a broadband light source and diffuse reflected spectra was employed, taking in the spectral region between 650 and 1000 nm and acquired at an angle of 90 deg at a position on the scalp ˜12 mm from the illumination site. The temperature at the onset of the experiment was ˜34°C (rectal temperature) with increasing intervals of 1°C until mouse death. The increase in temperature caused optical scattering signal changes consistent with a structural alteration of brain tissue, ultimately resulting in death. We have found that the peak absorbance intensity and its second derivative at specific wavelengths correlate well with temperature with an exponential dependence. Based on these findings, in order to estimate the influence of temperature on the internal brain tissue a reflectance-temperature index was established and was seen to correlate as well with measured temperature. Overall, results indicate variations in neural tissue properties during heatstroke and the feasibility to monitor and assess internal temperature variations using

  19. Application of attenuated total reflectance Fourier transform infrared spectroscopy in the mineralogical study of a landslide area, Hungary

    NASA Astrophysics Data System (ADS)

    Udvardi, Beatrix; Kovács, István János; Kónya, Péter; Földvári, Mária; Füri, Judit; Budai, Ferenc; Falus, György; Fancsik, Tamás; Szabó, Csaba; Szalai, Zoltán; Mihály, Judith

    2014-11-01

    This study demonstrates that the unpolarized attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR) is a practical and quick tool to distinguish different types of sediments in landslide-affected areas, and potentially other types of physical environments too. Identification and quantification of minerals by ATR FTIR is implemented on a set of powdered natural sediments from a loess landslide (Kulcs, Hungary). A protocol including sample preparation, analytical conditions and evaluation of sediment ATR spectra is outlined in order to identify and estimate major minerals in sediments. The comparison of the defined FTIR parameters against qualitative and quantitative results of X-ray diffraction and thermal analysis was used to validate the use of ATR FTIR spectroscopy for the considered sediments. The infrared band areas and their ratios (water/carbonates; silicates/carbonates; kaolinite) appear to be the most sensitive parameters to identify strongly weathered sediments such as paleosols and red clays which most likely facilitate sliding and could form sliding zones. The effect of grain size and orientation of anisotropic minerals on the wave number and intensity of some major absorption bands is also discussed.

  20. Rapid Quantification of Methamphetamine: Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics

    PubMed Central

    Hughes, Juanita; Ayoko, Godwin; Collett, Simon; Golding, Gary

    2013-01-01

    In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1%–78.6%) were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain. PMID:23936058

  1. Prediction of Soil Salinity Using Near-Infrared Reflectance Spectroscopy with Nonnegative Matrix Factorization.

    PubMed

    Chen, Hongyan; Zhao, Gengxing; Sun, Li; Wang, Ruiyan; Liu, Yaqiu

    2016-09-01

    As a key, yet difficult, issue currently in the quantitative remote sensing analysis of soil, the accurate and stable monitoring of soil salinity content (SSC) in situ should be studied and improved. The purpose of this study is to explore the method of fusing spectra outdoors with spectra indoors and improve the estimation precision of SSC based on near-infrared (NIR) reflectance hyper-spectra. First, samples of saline soil from the Yellow River delta of China were collected and analyzed. We measured three groups of sample spectra using a spectrometer: (1) situ-spectra, measured at sampling points in situ; (2) out-spectra, measured outdoors on air-dried samples; and, (3) lab-spectra, measured in a dark laboratory with the above air-dried samples. Second, four algorithms (multiplicative update, alternating least-squares, sparse affine non-negative matrix factorization (NMF), and gradient projection algorithms) of NMF were used to fuse the situ-spectra or out-spectra with the lab-spectra for the calibration of SSC. Finally, estimation models of SSC were built using the multiple linear regression method based on the first derivatives of the un-fused and fused spectra. The results indicate that using the NMF method to fuse the situ-spectra or out-spectra with the lab-spectra can heighten the correlation between SSC and the outdoor spectra in most wavelength ranges and improve the accuracy of the prediction model. The gradient projection algorithm shows the best performance with fewer variables and highest accuracy of the SSC model based on the NIR spectra. PMID:27566255

  2. Prediction of Soil Salinity Using Near-Infrared Reflectance Spectroscopy with Nonnegative Matrix Factorization.

    PubMed

    Chen, Hongyan; Zhao, Gengxing; Sun, Li; Wang, Ruiyan; Liu, Yaqiu

    2016-09-01

    As a key, yet difficult, issue currently in the quantitative remote sensing analysis of soil, the accurate and stable monitoring of soil salinity content (SSC) in situ should be studied and improved. The purpose of this study is to explore the method of fusing spectra outdoors with spectra indoors and improve the estimation precision of SSC based on near-infrared (NIR) reflectance hyper-spectra. First, samples of saline soil from the Yellow River delta of China were collected and analyzed. We measured three groups of sample spectra using a spectrometer: (1) situ-spectra, measured at sampling points in situ; (2) out-spectra, measured outdoors on air-dried samples; and, (3) lab-spectra, measured in a dark laboratory with the above air-dried samples. Second, four algorithms (multiplicative update, alternating least-squares, sparse affine non-negative matrix factorization (NMF), and gradient projection algorithms) of NMF were used to fuse the situ-spectra or out-spectra with the lab-spectra for the calibration of SSC. Finally, estimation models of SSC were built using the multiple linear regression method based on the first derivatives of the un-fused and fused spectra. The results indicate that using the NMF method to fuse the situ-spectra or out-spectra with the lab-spectra can heighten the correlation between SSC and the outdoor spectra in most wavelength ranges and improve the accuracy of the prediction model. The gradient projection algorithm shows the best performance with fewer variables and highest accuracy of the SSC model based on the NIR spectra.

  3. Attenuated total reflection surface-enhanced infrared absorption spectroscopy of carboxyl terminated self-assembled monolayers on gold.

    PubMed

    Goutev, Nikolay; Futamata, Masayuki

    2003-05-01

    A new recipe for surface-enhanced infrared absorption (SEIRA) active island Au films with improved adhesion in aqueous solution, low resistivity, and enhancement of the infrared (IR) absorption of about 300 was developed. The Au films prepared were utilized in studies of the ionization of self-assembled monolayers of 11-mercaptoundecanoic acid in Na2SO4 aqueous solutions by attenuated total reflection surface-enhanced infrared absorption (ATR-SEIRA) spectroscopy. It was found that the carboxyl end groups of the self-assembled monolayer turn into carboxylate anions on going from anodic to cathodic potentials or from acidic to alkaline pH. The water molecules close to the self-assembled monolayer in acidic solutions or at anodic potentials are preferentially aligned with their dipole moments parallel to the interface. This type of alignment can be ascribed to the dipole-dipole interaction between the carboxyl groups and the water molecules. On the other hand, in alkaline solutions or at cathodic potentials the structure of water close to the self-assembled monolayer is essentially bulk-like, with randomly oriented water molecules. This observation suggests that in alkaline solutions or at cathodic potentials the charge of the carboxylate anions is almost completely compensated for by strongly adsorbed counter cations. As a result, the electric field close to the surface of the ionized self-assembled monolayer is weak and has little influence on the orientation and hydrogen bonding of the water molecules.

  4. Prediction of Soil Organic Carbon at the European Scale by Visible and Near InfraRed Reflectance Spectroscopy

    PubMed Central

    Stevens, Antoine; Nocita, Marco; Tóth, Gergely; Montanarella, Luca; van Wesemael, Bas

    2013-01-01

    Soil organic carbon is a key soil property related to soil fertility, aggregate stability and the exchange of CO2 with the atmosphere. Existing soil maps and inventories can rarely be used to monitor the state and evolution in soil organic carbon content due to their poor spatial resolution, lack of consistency and high updating costs. Visible and Near Infrared diffuse reflectance spectroscopy is an alternative method to provide cheap and high-density soil data. However, there are still some uncertainties on its capacity to produce reliable predictions for areas characterized by large soil diversity. Using a large-scale EU soil survey of about 20,000 samples and covering 23 countries, we assessed the performance of reflectance spectroscopy for the prediction of soil organic carbon content. The best calibrations achieved a root mean square error ranging from 4 to 15 g C kg−1 for mineral soils and a root mean square error of 50 g C kg−1 for organic soil materials. Model errors are shown to be related to the levels of soil organic carbon and variations in other soil properties such as sand and clay content. Although errors are ∼5 times larger than the reproducibility error of the laboratory method, reflectance spectroscopy provides unbiased predictions of the soil organic carbon content. Such estimates could be used for assessing the mean soil organic carbon content of large geographical entities or countries. This study is a first step towards providing uniform continental-scale spectroscopic estimations of soil organic carbon, meeting an increasing demand for information on the state of the soil that can be used in biogeochemical models and the monitoring of soil degradation. PMID:23840459

  5. Near infrared reflectance spectroscopy as a tool for the control of sheep leather defatting.

    PubMed

    Cantero, R; Canals, T; Iturriaga, H

    2007-03-15

    The fat content is one of the variables to be controlled by the tanning industry with a view to obtaining leather for various commercial purposes. Ensuring the production of quality leather products frequently entails using some defatting treatment, particularly when the raw skin is rich in natural fat. The official method for determining fat in leather, IUC 4, is rather slow; also, it uses polluting reagents and involves powdering samples for Soxhlet extraction with low-polarity solvents. The combination of NIR diffuse reflectance spectroscopy as implemented with a fibre-optic probe and multivariate calibration is probably the best choice for the direct determination of fat in leather and the monitoring of leather defatting. In this work, a method for the determination of fat in leather and the control of the defatting process in an expeditious manner and with no sample treatment was developed. Defatting tests were conducted on leather specimens from lambs of various breeds and origins in order to span as wide as possible a range of variability in their properties and natural fat content. The NIR spectra used to construct the calibration matrices were recorded directly on the leather samples prior to and after defatting. Fat contents were determined by partial least-squares regression (PLSR), using the values obtained with the official method as references. Notwithstanding the complex nature of leather, the calibration models used provided good external predictions: the largest overall relative error, obtained by using a single calibration matrix for natural and defatted specimens, was 10%. The proposed method is therefore an advantageous alternative to the official method.

  6. Non-destructive evaluation of degradation in EB-PVD thermal barrier coatings by infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Flattum, Richard Y.; Cooney, Adam T.

    2013-01-01

    At room temperature and atmospheric conditions infrared reflectance spectroscopy and X-ray diffraction were employed for the detection of the phase transformation and residual stress within thermal barrier coatings (TBC). The TBC's samples initially consisted of the porous ceramic topcoat deposited by electron beam plasma vapor deposition, a bond coat and a superalloy substrate. Reflectance spectroscopy scans were performed from 7497 cm-1 to 68 cm-1 to analysis the fingerprint region as well as the chemical bonding region. These regions should indicate if a detectable change within the TBC response is a result of thermal degradation of the microstructure and the changes in yttrium dispersion throughout the yttrium stabilized zirconium. The thermal degradation was induced by thermal cycling the samples to 1100° C and then cooling them in an atmospheric environment. X-ray diffraction was also used to detect the phase composition within the TBC samples and see if either would clearly identify failure prior to actual spallation. The eventual measurability and quantify-ability of the phase changes within the TBC's may be used as an effective non-destructive evaluation (NDE) technique that would allow personnel in the field to know when servicing of the turbine blade was necessary.

  7. Preliminary evaluation of optical glucose sensing in red cell concentrations using near-infrared diffuse-reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Suzuki, Yusuke; Maruo, Katsuhiko; Zhang, Alice W.; Shimogaki, Kazushige; Ogawa, Hideto; Hirayama, Fumiya

    2012-01-01

    Bacterial contamination of blood products is one of the most frequent infectious complications of transfusion. Since glucose levels in blood supplies decrease as bacteria proliferate, it should be possible to detect the presence of bacterial contamination by measuring the glucose concentrations in the blood components. Hence this study is aimed to serve as a preliminary study for the nondestructive measurement of glucose level in transfusion blood. The glucose concentrations in red blood cell (RBC) samples were predicted using near-infrared diffuse-reflectance spectroscopy in the 1350 to 1850 nm wavelength region. Furthermore, the effects of donor, hematocrit level, and temperature variations among the RBC samples were observed. Results showed that the prediction performance of a dataset which contained samples that differed in all three parameters had a standard error of 29.3 mg/dL. Multiplicative scatter correction (MSC) preprocessing method was also found to be effective in minimizing the variations in scattering patterns created by various sample properties. The results suggest that the diffuse-reflectance spectroscopy may provide another avenue for the detection of bacterial contamination in red cell concentrations (RCC) products.

  8. Non-destructive evaluation of degradation in EB-PVD thermal barrier coatings by infrared reflectance spectroscopy

    SciTech Connect

    Flattum, Richard Y.; Cooney, Adam T.

    2013-01-25

    At room temperature and atmospheric conditions infrared reflectance spectroscopy and X-ray diffraction were employed for the detection of the phase transformation and residual stress within thermal barrier coatings (TBC). The TBC's samples initially consisted of the porous ceramic topcoat deposited by electron beam plasma vapor deposition, a bond coat and a superalloy substrate. Reflectance spectroscopy scans were performed from 7497 cm{sup -1} to 68 cm{sup -1} to analysis the fingerprint region as well as the chemical bonding region. These regions should indicate if a detectable change within the TBC response is a result of thermal degradation of the microstructure and the changes in yttrium dispersion throughout the yttrium stabilized zirconium. The thermal degradation was induced by thermal cycling the samples to 1100 Degree-Sign C and then cooling them in an atmospheric environment. X-ray diffraction was also used to detect the phase composition within the TBC samples and see if either would clearly identify failure prior to actual spallation. The eventual measurability and quantify-ability of the phase changes within the TBC's may be used as an effective non-destructive evaluation (NDE) technique that would allow personnel in the field to know when servicing of the turbine blade was necessary.

  9. Preliminary evaluation of optical glucose sensing in red cell concentrations using near-infrared diffuse-reflectance spectroscopy.

    PubMed

    Suzuki, Yusuke; Maruo, Katsuhiko; Zhang, Alice W; Shimogaki, Kazushige; Ogawa, Hideto; Hirayama, Fumiya

    2012-01-01

    Bacterial contamination of blood products is one of the most frequent infectious complications of transfusion. Since glucose levels in blood supplies decrease as bacteria proliferate, it should be possible to detect the presence of bacterial contamination by measuring the glucose concentrations in the blood components. Hence this study is aimed to serve as a preliminary study for the nondestructive measurement of glucose level in transfusion blood. The glucose concentrations in red blood cell (RBC) samples were predicted using near-infrared diffuse-reflectance spectroscopy in the 1350 to 1850 nm wavelength region. Furthermore, the effects of donor, hematocrit level, and temperature variations among the RBC samples were observed. Results showed that the prediction performance of a dataset which contained samples that differed in all three parameters had a standard error of 29.3 mg/dL. Multiplicative scatter correction (MSC) preprocessing method was also found to be effective in minimizing the variations in scattering patterns created by various sample properties. The results suggest that the diffuse-reflectance spectroscopy may provide another avenue for the detection of bacterial contamination in red cell concentrations (RCC) products. PMID:22352670

  10. Application of attenuated total reflectance Fourier transform infrared spectroscopy for determination of cefixime in oral pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Kandhro, Aftab A.; Laghari, Abdul Hafeez; Mahesar, Sarfaraz A.; Saleem, Rubina; Nelofar, Aisha; Khan, Salman Tariq; Sherazi, S. T. H.

    2013-11-01

    A quick and reliable analytical method for the quantitative assessment of cefixime in orally administered pharmaceutical formulations is developed by using diamond cell attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy as an easy procedure for quality control laboratories. The standards for calibration were prepared in aqueous medium ranging from 350 to 6000 mg/kg. The calibration model was developed based on partial least square (PLS) using finger print region of FT-IR spectrum in the range from 1485 to 887 cm-1. Excellent coefficient of determination (R2) was achieved as high as 0.99976 with root mean square error of 44.8 for calibration. The application of diamond cell (smart accessory) ATR FT-IR proves a reliable determination of cefixime in pharmaceutical formulations to assess the quality of the final product.

  11. Application of attenuated total reflectance Fourier transform infrared spectroscopy for determination of cefixime in oral pharmaceutical formulations.

    PubMed

    Kandhro, Aftab A; Laghari, Abdul Hafeez; Mahesar, Sarfaraz A; Saleem, Rubina; Nelofar, Aisha; Khan, Salman Tariq; Sherazi, S T H

    2013-11-01

    A quick and reliable analytical method for the quantitative assessment of cefixime in orally administered pharmaceutical formulations is developed by using diamond cell attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy as an easy procedure for quality control laboratories. The standards for calibration were prepared in aqueous medium ranging from 350 to 6000mg/kg. The calibration model was developed based on partial least square (PLS) using finger print region of FT-IR spectrum in the range from 1485 to 887cm(-1). Excellent coefficient of determination (R(2)) was achieved as high as 0.99976 with root mean square error of 44.8 for calibration. The application of diamond cell (smart accessory) ATR FT-IR proves a reliable determination of cefixime in pharmaceutical formulations to assess the quality of the final product.

  12. 2D attenuated total reflectance infrared spectroscopy reveals ultrafast vibrational dynamics of organic monolayers at metal-liquid interfaces

    NASA Astrophysics Data System (ADS)

    Kraack, Jan Philip; Lotti, Davide; Hamm, Peter

    2015-06-01

    We present two-dimensional infrared (2D IR) spectra of organic monolayers immobilized on thin metallic films at the solid liquid interface. The experiments are acquired under Attenuated Total Reflectance (ATR) conditions which allow a surface-sensitive measurement of spectral diffusion, sample inhomogeneity, and vibrational relaxation of the monolayers. Terminal azide functional groups are used as local probes of the environment and structural dynamics of the samples. Specifically, we investigate the influence of different alkyl chain-lengths on the ultrafast dynamics of the monolayer, revealing a smaller initial inhomogeneity and faster spectral diffusion with increasing chain-length. Furthermore, by varying the environment (i.e., in different solvents or as bare sample), we conclude that the most significant contribution to spectral diffusion stems from intra- and intermolecular dynamics within the monolayer. The obtained results demonstrate that 2D ATR IR spectroscopy is a versatile tool for measuring interfacial dynamics of adsorbed molecules.

  13. Differentiation of Body Fluid Stains on Fabrics Using External Reflection Fourier Transform Infrared Spectroscopy (FT-IR) and Chemometrics.

    PubMed

    Zapata, Félix; de la Ossa, Ma Ángeles Fernández; García-Ruiz, Carmen

    2016-04-01

    Body fluids are evidence of great forensic interest due to the DNA extracted from them, which allows genetic identification of people. This study focuses on the discrimination among semen, vaginal fluid, and urine stains (main fluids in sexual crimes) placed on different colored cotton fabrics by external reflection Fourier transform infrared spectroscopy (FT-IR) combined with chemometrics. Semen-vaginal fluid mixtures and potential false positive substances commonly found in daily life such as soaps, milk, juices, and lotions were also studied. Results demonstrated that the IR spectral signature obtained for each body fluid allowed its identification and the correct classification of unknown stains by means of principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). Interestingly, results proved that these IR spectra did not show any bands due to the color of the fabric and no substance of those present in daily life which were analyzed, provided a false positive. PMID:26896150

  14. 2D attenuated total reflectance infrared spectroscopy reveals ultrafast vibrational dynamics of organic monolayers at metal-liquid interfaces.

    PubMed

    Kraack, Jan Philip; Lotti, Davide; Hamm, Peter

    2015-06-01

    We present two-dimensional infrared (2D IR) spectra of organic monolayers immobilized on thin metallic films at the solid liquid interface. The experiments are acquired under Attenuated Total Reflectance (ATR) conditions which allow a surface-sensitive measurement of spectral diffusion, sample inhomogeneity, and vibrational relaxation of the monolayers. Terminal azide functional groups are used as local probes of the environment and structural dynamics of the samples. Specifically, we investigate the influence of different alkyl chain-lengths on the ultrafast dynamics of the monolayer, revealing a smaller initial inhomogeneity and faster spectral diffusion with increasing chain-length. Furthermore, by varying the environment (i.e., in different solvents or as bare sample), we conclude that the most significant contribution to spectral diffusion stems from intra- and intermolecular dynamics within the monolayer. The obtained results demonstrate that 2D ATR IR spectroscopy is a versatile tool for measuring interfacial dynamics of adsorbed molecules.

  15. [Detection of total nitrogen and organic matter in rhizosphere of transgenic cotton by near-infrared diffuse reflectance spectroscopy].

    PubMed

    Rui, Yu-kui; Huang, Kun-lun; Tian, Hui-qin; Guo, Jing; Luo, Yun-bo

    2007-01-01

    With the rapid development of the transgenic biotechnology, more and more transgenic plants have been poured into the market, and scientists have paid much attention to transgenic plants' ecological safety. To analysize the content of organic matter and total nitrogen in rhizosphere of transgenic cottons and their parents, the dried soil were scanned by continuous wave of near infrared diffuse reflectance spectroscopy ranging from 12,000 to 4 000 cm(-1) with a resolution of 4 cm(-1) and scanning for 64 times. Bruker OPUS software was applied for quantification. This method was compared with the standard methods. The results showed that the precision of NIRS was very similar to the standard methods. On the other hand, the results also showed that the contents of organic matter and total nitrogen in rhizosphere soil of transgenic cottons were significantly higher than those of their parents, which could arise from the foreign toxin secretion of root.

  16. Detection of Organic Matter in Sediments with Near-Infrared Reflectance Spectroscopy: Effects of Mineralogy, Albedo and Hydration

    NASA Astrophysics Data System (ADS)

    Kaplan, H. H.; Milliken, R.

    2014-12-01

    Laboratory, field-, and satellite-based visible-near infrared reflectance spectroscopy allows for rapid, remote, and non-destructive analysis of geologic materials to identify mineralogy as well as organic compounds. This type of analysis has potential to aid the search for organics on Mars as a means of first detection of reduced carbon, or to study organic matter nondestructively in valuable samples such as meteorites. In order to assess potential applications of this method we aim to answer fundamental questions about detection limits and quantification of organic matter using reflectance spectroscopy. Laboratory mixtures and natural samples are measured for total organic carbon (TOC in wt.%) with standard methods and reflectance spectroscopy. Absorption features due to C-H2 and C-H3 bonds are observed in the 3.3 to 3.5μm (3000 to 2850 cm-1) wavelength region. A strong H2O feature near 3μm, as well as carbonate-related absorptions near 3.4µm, are also found in this spectral region and can complicate detection of organic material, particularly at low TOC values. In natural samples without carbonate there appears to be a linear trend between TOC and the band depth of organic absorptions; samples that have low albedo, or strong 3μm water features deviate from this trend line. Spectra of samples with carbonate may be modeled with Gaussians to remove the influence of the carbonate features and better match the organic absorption trend. Early results indicate that quantification of organic matter in natural fine-grained samples using reflectance spectroscopy will need to take low-albedo components and water content into account. Detection limits may also depend on these properties; organic absorption features are clearly seen in the lowest TOC sample measured so far (0.08wt% or 800ppm), which is a relatively bright, carbonate-free, quartz- and clay-dominated outcrop sample. A series of laboratory experiments have been undertaken in which known amounts of organic

  17. Reflectance spectroscopy for soil analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last three decades or more, researchers have estimated soil properties using visible and near infrared (VNIR) diffuse reflectance spectroscopy (DRS), with varying results. This presentation reviews the history and state-of –the art of VNIR-DRS, including relative estimation accuracy for var...

  18. Use of Near Infrared Reflectance Spectroscopy to Predict Intake and Digestibility in Bulls and Steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fecal samples were collected from 282 growing Angus bulls over 4 yr to predict DMI of corn-silage-based diet. Contemporaneous digestion trials were conducted with the same diet in 12 steers for 3 yr and 12 bulls in 1 yr. Near-infrared spectra (n = 735 for growing bulls, n= = 240 for digestion trials...

  19. Direct determination of rosmarinic acid in Lamiaceae herbs using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and chemometrics.

    PubMed

    Saltas, Dimitrios; Pappas, Christos S; Daferera, Dimitra; Tarantilis, Petros A; Polissiou, Moschos G

    2013-04-01

    For the determination of rosmarinic acid (RA) directly in pulverized plant material, a method is developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) without any physicochemical pretreatment of samples. The RA content of 11 samples of eight different Lamiaceae herbs, as determined by high performance liquid chromatography (HPLC), varied between 86 ± 1 mg/g (in lemon balm) and 12.0 ± 0.8 mg/g (in hyssop) of dried plant material. The 11 samples and 50 other additional samples, which were prepared by mixing initial samples with KBr, were measured using DRIFTS. The second derivative of the spectral region 1344-806 cm(-1) was used and the corresponding data were analyzed using partial least squares (PLS) regression. The correlation between infrared spectral analysis and HPLC measurements shows that the DRIFTS method is sufficiently accurate, simple, and rapid. The RA content of the 11 Lamiaceae samples determined by DRIFTS ranged from 81 ± 4 mg/g (in lemon balm) to 12 ± 3 mg/g (in hyssop) of dried plant material. PMID:23496773

  20. Direct determination of rosmarinic acid in Lamiaceae herbs using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and chemometrics.

    PubMed

    Saltas, Dimitrios; Pappas, Christos S; Daferera, Dimitra; Tarantilis, Petros A; Polissiou, Moschos G

    2013-04-01

    For the determination of rosmarinic acid (RA) directly in pulverized plant material, a method is developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) without any physicochemical pretreatment of samples. The RA content of 11 samples of eight different Lamiaceae herbs, as determined by high performance liquid chromatography (HPLC), varied between 86 ± 1 mg/g (in lemon balm) and 12.0 ± 0.8 mg/g (in hyssop) of dried plant material. The 11 samples and 50 other additional samples, which were prepared by mixing initial samples with KBr, were measured using DRIFTS. The second derivative of the spectral region 1344-806 cm(-1) was used and the corresponding data were analyzed using partial least squares (PLS) regression. The correlation between infrared spectral analysis and HPLC measurements shows that the DRIFTS method is sufficiently accurate, simple, and rapid. The RA content of the 11 Lamiaceae samples determined by DRIFTS ranged from 81 ± 4 mg/g (in lemon balm) to 12 ± 3 mg/g (in hyssop) of dried plant material.

  1. Simultaneous infrared reflection absorption spectroscopy and quartz crystal microbalance measurements for in situ studies of the metal/atmosphere interface

    SciTech Connect

    Aastrup, T.; Leygraf, C.

    1997-09-01

    A new experimental setup for in situ studies of the metal/atmosphere interface has been developed based on simultaneous infrared reflection absorption spectroscopy (IRAS) and quartz crystal microbalance (QCM) measurements of a metal surface. It consists of an in situ chamber in which the metal can be exposed to a well-controlled atmosphere. Four external devices are connected to the in situ chamber; a Fourier transform infrared spectrometer with external optical compartments, a QCM sensor probe with a frequency counter, a corrosive air generator, and a corrosive air analyzing system. In order to demonstrate the capability of the IRAS/QCM setup, copper was exposed to purified air at 80% relative humidity and 25 C. Under these exposure conditions, the interface between copper and air consists of cuprous oxide and water physisorbed on the oxide. The kinetics of the cuprous oxide formation could be followed in situ with both techniques. The combined IRAS/QCM results show excellent agreement with previous combined IRAS and cathodic reduction measurements and with optical calculations of the IRAS response. Under these conditions, the detection limit in terms of an equivalent Cu{sub 2}O film thickness is 10 {angstrom} for IRAS in situ analysis and 2 {angstrom} for QCM in situ analysis, respectively.

  2. Noninvasive observation of skeletal muscle contraction using near-infrared time-resolved reflectance and diffusing-wave spectroscopy.

    PubMed

    Belau, Markus; Ninck, Markus; Hering, Gernot; Spinelli, Lorenzo; Contini, Davide; Torricelli, Alessandro; Gisler, Thomas

    2010-01-01

    We introduce a method for noninvasively measuring muscle contraction in vivo, based on near-infrared diffusing-wave spectroscopy (DWS). The method exploits the information about time-dependent shear motions within the contracting muscle that are contained in the temporal autocorrelation function g(1)(τ,t) of the multiply scattered light field measured as a function of lag time, τ, and time after stimulus, t. The analysis of g(1)(τ,t) measured on the human M. biceps brachii during repetitive electrical stimulation, using optical properties measured with time-resolved reflectance spectroscopy, shows that the tissue dynamics giving rise to the speckle fluctuations can be described by a combination of diffusion and shearing. The evolution of the tissue Cauchy strain e(t) shows a strong correlation with the force, indicating that a significant part of the shear observed with DWS is due to muscle contraction. The evolution of the DWS decay time shows quantitative differences between the M. biceps brachii and the M. gastrocnemius, suggesting that DWS allows to discriminate contraction of fast- and slow-twitch muscle fibers. PMID:21054123

  3. Noninvasive observation of skeletal muscle contraction using near-infrared time-resolved reflectance and diffusing-wave spectroscopy

    NASA Astrophysics Data System (ADS)

    Belau, Markus; Ninck, Markus; Hering, Gernot; Spinelli, Lorenzo; Contini, Davide; Torricelli, Alessandro; Gisler, Thomas

    2010-09-01

    We introduce a method for noninvasively measuring muscle contraction in vivo, based on near-infrared diffusing-wave spectroscopy (DWS). The method exploits the information about time-dependent shear motions within the contracting muscle that are contained in the temporal autocorrelation function g(1)(τ,t) of the multiply scattered light field measured as a function of lag time, τ, and time after stimulus, t. The analysis of g(1)(τ,t) measured on the human M. biceps brachii during repetitive electrical stimulation, using optical properties measured with time-resolved reflectance spectroscopy, shows that the tissue dynamics giving rise to the speckle fluctuations can be described by a combination of diffusion and shearing. The evolution of the tissue Cauchy strain e(t) shows a strong correlation with the force, indicating that a significant part of the shear observed with DWS is due to muscle contraction. The evolution of the DWS decay time shows quantitative differences between the M. biceps brachii and the M. gastrocnemius, suggesting that DWS allows to discriminate contraction of fast- and slow-twitch muscle fibers.

  4. Application of multibounce attenuated total reflectance fourier transform infrared spectroscopy and chemometrics for determination of aspartame in soft drinks.

    PubMed

    Khurana, Harpreet Kaur; Cho, Il Kyu; Shim, Jae Yong; Li, Qing X; Jun, Soojin

    2008-02-13

    Aspartame is a low-calorie sweetener commonly used in soft drinks; however, the maximum usage dose is limited by the U.S. Food and Drug Administration. Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance sampling accessory and partial least-squares regression (PLS) was used for rapid determination of aspartame in soft drinks. On the basis of spectral characterization, the highest R2 value, and lowest PRESS value, the spectral region between 1600 and 1900 cm(-1) was selected for quantitative estimation of aspartame. The potential of FTIR spectroscopy for aspartame quantification was examined and validated by the conventional HPLC method. Using the FTIR method, aspartame contents in four selected carbonated diet soft drinks were found to average from 0.43 to 0.50 mg/mL with prediction errors ranging from 2.4 to 5.7% when compared with HPLC measurements. The developed method also showed a high degree of accuracy because real samples were used for calibration, thus minimizing potential interference errors. The FTIR method developed can be suitably used for routine quality control analysis of aspartame in the beverage-manufacturing sector.

  5. Determination of antioxidant capacity and phenolic content of chocolate by attenuated total reflectance-Fourier transformed-infrared spectroscopy.

    PubMed

    Hu, Yaxi; Pan, Zhi Jie; Liao, Wen; Li, Jiaqi; Gruget, Pierre; Kitts, David D; Lu, Xiaonan

    2016-07-01

    Antioxidant capacity and phenolic content of chocolate, containing different amounts of cacao (35-100%), were determined using attenuated total reflectance (ATR)-Fourier transformed-infrared (FT-IR) spectroscopy (4000-550cm(-1)). Antioxidant capacities were first characterized using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity) assays. Phenolic contents, including total phenol and procyanidins monomers, were quantified using the Folin-Ciocalteu assay and high performance liquid chromatography coupled with photodiode array detector (HPLC-DAD), respectively. Five partial least-squares regression (PLSR) models were constructed and cross-validated using FT-IR spectra from 18 types of chocolate and corresponding reference values determined using DPPH, ORAC, Folin-Ciocalteu, and HPLC assays. The models were validated using seven unknown samples of chocolate. PLSR models showed good prediction capability for DPPH [R(2)-P (prediction)=0.88, RMSEP (root mean squares error of prediction)=12.62μmol Trolox/g DFW], ORAC (R(2)-P=0.90, RMSEP=37.92), Folin-Ciocalteu (R(2)-P=0.88, RMSEP=5.08), and (+)-catechin (R(2)-P=0.86, RMSEP=0.10), but lacked accuracy in the prediction of (-)-epicatechin (R(2)-P=0.72, RMSEP=0.57). ATR-FT-IR spectroscopy can be used for rapid prediction of antioxidant capacity, total phenolic content, and (+)-catechin in chocolate. PMID:26920292

  6. Dehydration of uranyl nitrate hexahydrate to the trihydrate under ambient conditions as observed via dynamic infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-01

    Uranyl nitrate is a key species in the nuclear fuel cycle, but is known to exist in different states of hydration, including the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating it. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  7. Quantitative determination of molecular structure in multilayered thin films of biaxial and lower symmetry from photon spectroscopies. I. Reflection infrared vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Parikh, Atul N.; Allara, David L.

    1992-01-01

    A semitheoretical formalism based on classical electromagnetic wave theory has been developed for application to the quantitative treatment of reflection spectra from multilayered anisotropic films on both metallic and nonmetallic substrates. Both internal and external reflection experiments as well as transmission can be handled. The theory is valid for all wavelengths and is appropriate, therefore, for such experiments as x-ray reflectivity, uv-visible spectroscopic ellipsometry, and infrared reflection spectroscopy. Further, the theory is applicable to multilayered film structures of variable number of layers, each with any degree of anisotropy up to and including full biaxial symmetry. The reflectivities (and transmissivities) are obtained at each frequency by solving the wave propagation equations using a rigorous 4×4 transfer matrix method developed by Yeh in which the optical functions of each medium are described in the form of second rank (3×3) tensors. In order to obtain optical tensors for materials not readily available in single crystal form, a method has been developed to evaluate tensor elements from the complex scalar optical functions (n̂) obtained from the isotropic material with the limitations that the molecular excitations are well characterized and obey photon-dipole selection rules. This method is intended primarily for infrared vibrational spectroscopy and involves quantitative decomposition of the isotropic imaginary optical function (k) spectrum into a sum of contributions from fundamental modes, the assignment of a direction in molecular coordinates to the transition dipole matrix elements for each mode, the appropriate scaling of each k vector component in surface coordinates according to a selected surface orientation of the molecule to give a diagonal im(n̂) tensor, and the calculation of the real(n̂) spectrum tensor elements by the Kramers-Kronig transformation. Tensors for other surface orientations are generated by an

  8. Toward a UV-visible-near-infrared hyperspectral imaging platform for fast multiplex reflection spectroscopy.

    PubMed

    Li, Jianping; Chan, Robert K Y

    2010-10-15

    A reflection hyperspectral imaging system covering a 350-1000nm spectral range is realized by a UV-visible-near-IR Fourier transform imaging spectrometer. The system has a simple design and good spectral and spatial resolving performance. Accurate and fast microspectroscopic measurement results on novel colloidal crystal beads demonstrate the system has practical potential for high-throughput molecular multiplex assays. PMID:20967056

  9. Characterization of the hydration state of pharmaceuticals by variable-temperature diffuse-reflectance infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Wasacz, Frank M.; Strand, Scott W.; Bugay, David E.; Morris, Kenneth R.

    1992-03-01

    The characterization of hydrates is exceedingly important for pharmaceuticals since the state of hydration of a drug can effect its solubility, dissolution rate, bioavailability, chemical stability, and the physical stability of subsequent dosage forms. In addition, the United States Food and Drug Administration concerns about the above issue make complete characterization of hydrates a necessary part of investigative new drug filings. A Collector TM Diffuse Reflectance accessory fitted with a controlled Environmental Chamber was used to study drug formulations under varying temperature and humidity conditions.

  10. Near-infrared reflectance spectroscopy for predicting amino acids content in intact processed animal proteins.

    PubMed

    De la Haba, Maria José; Garrido-Varo, Ana; Guerrero-Ginel, José Emilio; Pérez-Marín, Dolores C

    2006-10-01

    Near-infrared calibrations were developed for the instantaneous prediction of amino acids composition of processed animal proteins (PAPs). Two sample presentation modes were compared (ground vs intact) for demonstrating the viability of the analysis in the intact form, avoiding the need for milling. Modified partial least-squares (MPLS) equations for the prediction of amino acids in PAPs were developed using the same set of samples (N = 92 PAPs) analyzed in ground and intact form and in three cups differing in the optical window size. The standard error for cross validation (SECV) and the coefficient of determination (1-VR) values yielded with the calibrations developed using the samples analyzed in the intact form showed similar or even better accuracy than those obtained with finely ground samples. The excellent predictive ability (1-VR > 0.90; CV < 3.0%) obtained for the prediction of amino acids in intact processed animal proteins opens an enormous expectative for the on-line implementation of NIRS technology in the processing and marketing of these important protein feed ingredients, alleviating the costs and time associated with the routine quality controls.

  11. Infrared spectroscopy of Comet Kohoutek. [and reflection studies of frost spectra

    NASA Technical Reports Server (NTRS)

    Fink, U.

    1975-01-01

    Interferometry observations from 90-in. and 61-in. telescopes tracking the Comet Kohoutek are summarized. Laboratory reflection studies of ices potentially useful for future cometary work were conducted. The frosts studied included: H2O, CO2 NH3, H2S, CH4, NH4HS, and ammonia polysulfide. The frost spectra show remarkable changes with the temperatures, particularly in the case of hydrogen sulfide. Additional analysis found the variation in the H2S ice spectrum to be due to a phase change from a low temperature tetragonal unit cube to a higher temperature face-centered cubic structure. The spectra data indicate that if frost spectra are required for comparison with observed cometary or planetary absorption, the temperature of the frost must be matched.

  12. The use of near-infrared reflectance spectroscopy in the prediction of the chemical composition of goose fatty liver.

    PubMed

    Molette, C; Berzaghi, P; Zotte, A D; Remignon, H; Babile, R

    2001-11-01

    The use of near-infrared reflectance spectroscopy (NIRS) on a meat product is described in this report. The aim of the study was to develop calibration equations to predict the chemical composition of goose fatty liver (foie gras) with lipid contents greater than 40% of the fresh pate. Spectra of 52 foie gras samples were collected in the visible and NIR region (400 to 2,498 nm). Calibration equations were computed for DM, CP, lipids and fatty acids using modified partial least-squares regression. R2 values were high for the total lipid content (0.805) and DM (0.908) but were low for ash (0.151) and relatively low for protein content (0.255). For the major fatty acids, R2 ranged from 0.886 for palmitic acid to 0.988 for oleic acid. Oleic acid, the main fatty acid of the liver, and the stearic acid had higher R2 values than the less represented fatty acids. This study suggests that the NIRS technique can be used to predict lipid content and the fatty acid composition of goose fatty livers, but calibration must be built on a larger number of samples to generate accurate predictions.

  13. Enhanced Single Seed Trait Predictions in Soybean (Glycine max) and Robust Calibration Model Transfer with Near-Infrared Reflectance Spectroscopy.

    PubMed

    Hacisalihoglu, Gokhan; Gustin, Jeffery L; Louisma, Jean; Armstrong, Paul; Peter, Gary F; Walker, Alejandro R; Settles, A Mark

    2016-02-10

    Single seed near-infrared reflectance (NIR) spectroscopy predicts soybean (Glycine max) seed quality traits of moisture, oil, and protein. We tested the accuracy of transferring calibrations between different single seed NIR analyzers of the same design by collecting NIR spectra and analytical trait data for globally diverse soybean germplasm. X-ray microcomputed tomography (μCT) was used to collect seed density and shape traits to enhance the number of soybean traits that can be predicted from single seed NIR. Partial least-squares (PLS) regression gave accurate predictive models for oil, weight, volume, protein, and maximal cross-sectional area of the seed. PLS models for width, length, and density were not predictive. Although principal component analysis (PCA) of the NIR spectra showed that black seed coat color had significant signal, excluding black seeds from the calibrations did not impact model accuracies. Calibrations for oil and protein developed in this study as well as earlier calibrations for a separate NIR analyzer of the same design were used to test the ability to transfer PLS regressions between platforms. PLS models built from data collected on one NIR analyzer had minimal differences in accuracy when applied to spectra collected from a sister device. Model transfer was more robust when spectra were trimmed from 910 to 1679 nm to 955-1635 nm due to divergence of edge wavelengths between the two devices. The ability to transfer calibrations between similar single seed NIR spectrometers facilitates broader adoption of this high-throughput, nondestructive, seed phenotyping technology.

  14. Near-infrared reflectance spectroscopy as a novel method to detect demyelination in rat sciatic nerve in vivo

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Harsha; Senapati, Arun; Peng, Yuan Bo; Kashyap, Dheerendra; Liu, Hanli

    2005-04-01

    This study was done to use near infrared (NIR) spectroscopy to bring out differences in the anatomical substructures in the rat spinal cord and further to differentiate scattering between demyelinated and normal sciatic nerves in rat models, thereby exploring a new methodology to localize MS (multiple Sclerosis) lesions in vivo for animal studies. The experimental setup consisted of a tungsten light source, CCD array spectrometer, and bifurcated optical fibers for light delivery and detection of back scattered light from tissue. The measurement system was calibrated with reflectance standard. The spinal cord of 14 rats was exposed by laminectomy, and the measurements were taken on 8 points at intervals of 1 mm on the right and left lumbar-sacral regions and the central blood vessel. For measurements on the sciatic nerve, the spinal nerves of 84 rats were ligated according to the Chung Model. Measurements were taken on five points on both the ligated and the control nerve side after 1, 4, 7 and 14 days. The reduced scattering coefficient, μs', was found to be higher in the lumbar-sacral regions (34.17 +/- 2.05 cm-1) than that near the central blood vessel (19.9 +/- 3.8 cm-1). Statistically, there was significant difference in scattering between the control side and the ligated side on postoperative days 4, 7, and 14. This study shows a promising diagnostic value in the future for monitoring of demyelinated CNS (central nervous system) diseases, like Multiple Sclerosis.

  15. In-situ observations of adsorption and film formation on metal electrodes by synchrotron far infrared reflectance spectroscopy.

    SciTech Connect

    Bowmaker, G. A.; Hahn, F.; Leger, J. M.; Melendres, C. A.

    1999-05-17

    Adsorption and film formation are key processes associated with the passivation and inhibition of metallic corrosion. New experimental approaches are needed to advance our knowledge in these areas. We have developed the technique of Synchrotron Far Infrared Reflectance Spectroscopy (SFIRS) for in situ investigations of the structure and composition of surface films and adsorbed layers on metals. We demonstrate its application to the determination of the nature of surface films on copper in aqueous solutions and the adsorption of anions on gold. The anodic corrosion films on copper in alkaline solution were found to consist of Cu{sub 2}O in the passive region at about {minus}0.05 V vs SCE and CUO, together with CU(OH){sub 2}, at 0.30 V. We have also observed for the first time the adsorption of anions at monolayer coverage on the surface of a gold electrode in perchloric acid solution. Halides (Cl-, Br-), nitrate, sulfate, and phosphate have been studied. When two different anions are present in solution, the more strongly adsorbed species determines the corrosion behavior of the metal. This is illustrated in the competitive adsorption of bromide and phosphate on gold.

  16. Monitoring closed head injury induced changes in brain physiology with orthogonal diffuse near-infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Abookasis, David; Shochat, Ariel; Mathews, Marlon S.

    2014-03-01

    We applied an orthogonal diffuse reflectance spectroscopy (o-DRS) to assess brain physiology following closed head injury (CHI). CHI was induced in anesthetized male mice by weight-drop device using ~50gram cylindrical metal falling from a height of 90 cm onto the intact scalp. A total of twenty-six mice were used in the experiments divided randomly into three groups as follows: Group 1 (n=11) consisted of injured mice monitored for 1 hour every 10 minutes. Group 2 (n=10) were the control mice not experience CHI. Group 3 (n=5) consisted of injured mice monitored every minute up to 20 minutes. Measurement of optical quantities of brain tissue (absorption and reduced scattering coefficients) in the near-infrared window from 650 to 1000 nm were carried out by employing different source-detector distances and locations to provide depth sensitivity. With respect to baseline, we found difference in brain hemodynamic properties following injury. In addition, o-DRS successfully evaluate the structural variations likely from evolving cerebral edema throughout exploring the scattering spectral shape.

  17. Left Prefrontal Activity Reflects the Ability of Vicarious Fear Learning: A Functional Near-Infrared Spectroscopy Study

    PubMed Central

    Ma, Qingguo; Wang, Lei

    2013-01-01

    Fear could be acquired indirectly via social observation. However, it remains unclear which cortical substrate activities are involved in vicarious fear transmission. The present study was to examine empathy-related processes during fear learning by-proxy and to examine the activation of prefrontal cortex by using functional near-infrared spectroscopy. We simultaneously measured participants' hemodynamic responses and skin conductance responses when they were exposed to a movie. In this movie, a demonstrator (i.e., another human being) was receiving a classical fear conditioning. A neutral colored square paired with shocks (CSshock) and another colored square paired with no shocks (CSno-shock) were randomly presented in front of the demonstrator. Results showed that increased concentration of oxygenated hemoglobin in left prefrontal cortex was observed when participants watched a demonstrator seeing CSshock compared with that exposed to CSno-shock. In addition, enhanced skin conductance responses showing a demonstrator's aversive experience during learning object-fear association were observed. The present study suggests that left prefrontal cortex, which may reflect speculation of others' mental state, is associated with social fear transmission. PMID:24307877

  18. Left prefrontal activity reflects the ability of vicarious fear learning: a functional near-infrared spectroscopy study.

    PubMed

    Ma, Qingguo; Huang, Yujing; Wang, Lei

    2013-01-01

    Fear could be acquired indirectly via social observation. However, it remains unclear which cortical substrate activities are involved in vicarious fear transmission. The present study was to examine empathy-related processes during fear learning by-proxy and to examine the activation of prefrontal cortex by using functional near-infrared spectroscopy. We simultaneously measured participants' hemodynamic responses and skin conductance responses when they were exposed to a movie. In this movie, a demonstrator (i.e., another human being) was receiving a classical fear conditioning. A neutral colored square paired with shocks (CS(shock)) and another colored square paired with no shocks (CS(no-shock)) were randomly presented in front of the demonstrator. Results showed that increased concentration of oxygenated hemoglobin in left prefrontal cortex was observed when participants watched a demonstrator seeing CS(shock) compared with that exposed to CS(no-shock). In addition, enhanced skin conductance responses showing a demonstrator's aversive experience during learning object-fear association were observed. The present study suggests that left prefrontal cortex, which may reflect speculation of others' mental state, is associated with social fear transmission. PMID:24307877

  19. The application of Near-Infrared Reflectance Spectroscopy (NIRS) to detect melamine adulteration of soya bean meal.

    PubMed

    Haughey, Simon A; Graham, Stewart F; Cancouët, Emmanuelle; Elliott, Christopher T

    2013-02-15

    Soya bean products are used widely in the animal feed industry as a protein based feed ingredient and have been found to be adulterated with melamine. This was highlighted in the Chinese scandal of 2008. Dehulled soya (GM and non-GM), soya hulls and toasted soya were contaminated with melamine and spectra were generated using Near Infrared Reflectance Spectroscopy (NIRS). By applying chemometrics to the spectral data, excellent calibration models and prediction statistics were obtained. The coefficients of determination (R(2)) were found to be 0.89-0.99 depending on the mathematical algorithm used, the data pre-processing applied and the sample type used. The corresponding values for the root mean square error of calibration and prediction were found to be 0.081-0.276% and 0.134-0.368%, respectively, again depending on the chemometric treatment applied to the data and sample type. In addition, adopting a qualitative approach with the spectral data and applying PCA, it was possible to discriminate between the four samples types and also, by generation of Cooman's plots, possible to distinguish between adulterated and non-adulterated samples.

  20. In situ Studies of Soft- and Reactive Landing of Mass-Selected Ions Using Infrared Reflection Absorption Spectroscopy

    SciTech Connect

    Hu, Qichi; Wang, Peng; Gassman, Paul L.; Laskin, Julia

    2009-09-01

    Grazing incidence infrared reflection absorption spectroscopy (IRRAS) for in situ and in real time characterization of substrates modified by soft- and reactive landing (SL and RL) of complex ions was implemented on a mass-selected ion deposition instrument. Ions produced by electrospray ionization were mass-selected using a quadrupole mass filter and deposited onto inert and reactive self-assembled monolayer (SAM) surfaces. Surface composition during and after ion deposition was monitored using IRRAS. Physisorption of a cyclic peptide, Garmicidin S (GS), was studied for 8 hrs during deposition and additional 12 hrs after the end of deposition. The integrated signal of the characteristic amide bands followed a linear increase during the deposition and stayed unchanged after the deposition was finished. Similar linear increase in IRRAS signal was obtained following reactive deposition of the protonated dodecanediamine onto SAMs of dithiobis (succinimidyl undecanoate) (NHS-SAM) and 16-mercaptohexadecanoic acid fluoride (COF-SAM) on gold. IRRAS allowed us to monitor for the first time the formation of the amide bond between reactive SAM surfaces and the projectile molecule.

  1. A novel, direct, reagent-free method for the detection of beeswax adulteration by single-reflection attenuated total reflectance mid-infrared spectroscopy.

    PubMed

    Maia, Miguel; Barros, Ana I R N A; Nunes, Fernando M

    2013-03-30

    In this work, a novel, direct, reagent-free method for the detection of beeswax adulteration by paraffin, microcrystalline wax, tallow and stearic acid using single-reflection attenuated total reflectance mid-infrared spectroscopy was developed. The use of the absorbance ratios of [Formula: see text] , [Formula: see text] and [Formula: see text] allows a minimum of 5% paraffin/microcrystalline wax and tallow adulteration and 0.5% stearic acid adulteration of beeswax to be detected. The upper and lower critical limits for beeswax authenticity were established from the analysis of virgin beeswax and were validated by independent analysis of real sheet and comb beeswax samples using high-temperature gas chromatography with flame-ionization detection. In addition to its simplicity with respect to sample handling, the amount of sample and the time needed are far less than those required in previously described methods, which are based on chemical analysis and chromatographic techniques. These advantages result in time and cost savings, an increase in the number of samples that can be analyzed, and, most importantly, the detection of the main beeswax adulterants using a single method.

  2. Diffuse Reflectance Mid-Infrared Spectroscopy as a Tool for the Identification of Surface Contamination on Sandblasted Metals

    NASA Technical Reports Server (NTRS)

    Powell, Louis G.; Barber, Tye E.; Neu, John T.; Nerren, Billy H.

    1997-01-01

    The SOC 400 Surface Inspection Machine/Infrared (SIMIR) is a small, ruggedized Fourier transform infrared spectrometer having dedicated diffuse reflectance optics. The SOC 400 was designed for the purpose of detecting (qualitatively and quantitatively) oil stains on the inside surface of solid rocket motor casings in the as-sandblasted and cleaned condition at levels approaching 1 mg. sq ft. The performance of this instrument is described using spectral mapping techniques.

  3. Diffuse reflectance mid-infrared spectroscopy as a tool for the identification of surface contamination on sandblasted metals

    SciTech Connect

    Powell, G.L.; Barber, T.E.; Neu, J.T.; Nerren, B.H.

    1996-07-30

    The SOC 400 Surface Inspection Machine/Infrared (SIMIR) is a small, ruggedized Fourier transform infrared spectrometer having dedicated diffuse reflectance optics. The SOC 400 was designed for the purpose of detecting (qualitatively and quantitatively) oil stains on the inside surface of solid rocket motor casings in the as-sandblasted and cleaned condition at levels approaching 1 mg ft{sup {minus}2}. The performance of this instrument is described using spectral mapping techniques.

  4. Dehydration of Uranyl Nitrate Hexahydrate to Uranyl Nitrate Trihydrate under Ambient Conditions as Observed via Dynamic Infrared Reflectance Spectroscopy

    SciTech Connect

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-22

    the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating them. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  5. Fourier Transform Infrared Spectroscopy Part III. Applications.

    ERIC Educational Resources Information Center

    Perkins, W. D.

    1987-01-01

    Discusses the use of the FT-IR spectrometer in analyses that were previously avoided. Examines some of the applications of this spectroscopy with aqueous solutions, circular internal reflection, samples with low transmission, diffuse reflectance, infrared emission, and the infrared microscope. (TW)

  6. Comparative study of Fourier transform infrared spectroscopy in transmission, attenuated total reflection, and total reflection modes for the analysis of plastics in the cultural heritage field.

    PubMed

    Picollo, Marcello; Bartolozzi, Giovanni; Cucci, Costanza; Galeotti, Monica; Marchiafava, Veronica; Pizzo, Benedetto

    2014-01-01

    This study was completed within the framework of two research projects dealing with the conservation of contemporary artworks. The first is the Seventh Framework Project (FP7) of the European Union, Preservation of Plastic ARTefacts in Museum Collections (POPART), spanning years 2008-2012, and the second is the Italian project funded by the Tuscan Region, Preventive Conservation of Contemporary Art (Conservazione Preventiva dell'Arte Contemporanea (COPAC)), spanning 2011-2013. Both of these programs pointed out the great importance of having noninvasive and portable analytical techniques that can be used to investigate and characterize modern and contemporary artworks, especially those consisting of synthetic polymers. Indeed, despite the extensive presence of plastics in museum collections, there is still a lack of analytical tools for identifying, characterizing, and setting up adequate conservation strategies for these materials. In this work, the potentials of in situ and noninvasive Fourier transform infrared (FT-IR) spectroscopy, implemented by means of portable devices that operate in reflection mode, are investigated with a view to applying the results in large-scale surveys of plastic objects in museums. To this end, an essential prerequisite are the reliability of spectral data acquired in situ and the availability of spectral databases acquired from reference materials. A collection of polymeric samples, which are available commercially as ResinKit, was analyzed to create a reference spectral archive. All the spectra were recorded using three FT-IR configurations: transmission (trans), attenuated total reflection (ATR), and total reflection (TR). A comparative evaluation of the data acquired using the three instrumental configurations is presented, together with an evaluation of the similarity percentages and a discussion of the critical cases.

  7. The applicability of reflectance micro-Fourier-transform infrared spectroscopy for the detection of synthetic microplastics in marine sediments.

    PubMed

    Harrison, Jesse P; Ojeda, Jesús J; Romero-González, María E

    2012-02-01

    Synthetic microplastics (≤5-mm fragments) are globally distributed contaminants within coastal sediments that may transport organic pollutants and additives into food webs. Although micro-Fourier-transform infrared (micro-FT-IR) spectroscopy represents an ideal method for detecting microplastics in sediments, this technique lacks a standardized operating protocol. Herein, an optimized method for the micro-FT-IR analysis of microplastics in vacuum-filtered sediment retentates was developed. Reflectance micro-FT-IR analyses of polyethylene (PE) were compared with attenuated total reflectance FT-IR (ATR-FT-IR) measurements. Molecular mapping as a precursor to the imaging of microplastics was explored in the presence and absence of 150-μm PE fragments, added to sediment at concentrations of 10, 100, 500 and 1000ppm. Subsequently, polymer spectra were assessed across plastic-spiked sediments from fifteen offshore sites. While all spectra obtained of evenly shaped plastics were typical to PE, reflectance micro-FT-IR measurements of irregularly shaped materials must account for refractive error. Additionally, we provide the first evidence that mapping successfully detects microplastics without their visual selection for characterization, despite this technique relying on spectra from small and spatially separated locations. Flotation of microplastics from sediments only enabled a fragment recovery rate of 61 (±31 S.D.) %. However, mapping 3-mm(2) areas (within 47-mm filters) detected PE at spiking concentrations of 100ppm and above, displaying 69 (±12 S.D.) % of the fragments in these locations. Additionally, mapping detected a potential PE fragment in a non-spiked retentate. These data have important implications for research into the imaging of microplastics. Specifically, the sensitivity and spatial resolution of the present protocol may be improved by visualizing the entire filter with high-throughput detection techniques (e.g., focal plane array-based imaging

  8. Fast and inexpensive detection of total and extractable element concentrations in aquatic sediments using near-infrared reflectance spectroscopy (NIRS).

    PubMed

    Kleinebecker, Till; Poelen, Moni D M; Smolders, Alfons J P; Lamers, Leon P M; Hölzel, Norbert

    2013-01-01

    Adequate biogeochemical characterization and monitoring of aquatic ecosystems, both for scientific purposes and for water management, pose high demands on spatial and temporal replication of chemical analyses. Near-infrared reflectance spectroscopy (NIRS) may offer a rapid, low-cost and reproducible alternative to standard analytical sample processing (digestion or extraction) and measuring techniques used for the chemical characterization of aquatic sediments. We analyzed a total of 191 sediment samples for total and NaCl-extractable concentrations of Al, Ca, Fe, K, Mg, Mn, N, Na, P, S, Si, and Zn as well as oxalate- extractable concentrations of Al, Fe, Mn and P. Based on the NIR spectral data and the reference values, calibration models for the prediction of element concentrations in unknown samples were developed and tested with an external validation procedure. Except Mn, all prediction models of total element concentrations were found to be acceptable to excellent (ratio of performance deviation: RPD 1.8-3.1). For extractable element fractions, viable model precision could be achieved for NaCl-extractable Ca, K, Mg, NH4 (+)-N, S and Si (RPD 1.7-2.2) and oxalate-extractable Al, Fe and P (RPD 1.9-2.3). For those elements that showed maximum total values below 3 g kg(-1) prediction models were found to become increasingly critical (RPD <2.0). Low concentrations also limited the performance of NIRS calibrations for extracted elements, with critical concentration thresholds <0.1 g kg(-1) and 3.3 g kg(-1) for NaCl and oxalate extractions, respectively. Thus, reliable NIRS measurements of trace metals are restricted to sediments with high metal content. Nevertheless, we demonstrated the suitability of NIRS measurements to determine a large array of chemical properties of aquatic sediments. The results indicate great potential of this fast technique as an analytical tool to better understand the large spatial and temporal variation of sediment characteristics in an

  9. Quantitative determination of competitive molecular adsorption on gold nanoparticles using attenuated total reflectance-Fourier transform infrared spectroscopy.

    PubMed

    Tsai, De-Hao; Davila-Morris, Melissa; DelRio, Frank W; Guha, Suvajyoti; Zachariah, Michael R; Hackley, Vincent A

    2011-08-01

    Surface-sensitive quantitative studies of competitive molecular adsorption on nanoparticles were conducted using a modified attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy method. Adsorption isotherms for thiolated poly(ethylene glycol) (SH-PEG) on gold nanoparticles (AuNPs) as a function of molecular mass (1, 5, and 20 kDa) were characterized. We find that surface density of SH-PEG on AuNPs is inversely proportional to the molecular mass (M(m)). Equilibrium binding constants for SH-PEG, obtained using the Langmuir adsorption model, show the binding affinity for SH-PEG is proportional to M(m). Simultaneous competitive adsorption between mercaptopropionic acid (MPA) and 5 kDa SH-PEG (SH-PEG5K) was investigated, and we find that MPA concentration is the dominant factor influencing the surface density of both SH-PEG5K and MPA, whereas the concentration of SH-PEG5K affects only SH-PEG5K surface density. Electrospray differential mobility analysis (ES-DMA) was employed as an orthogonal characterization technique. ES-DMA results are consistent with the results obtained by ATR-FTIR, confirming our conclusions about the adsorption process in this system. Ligand displacement competitive adsorption, where the displacing molecular species is added after completion of the ligand surface binding, was also interrogated by ATR-FTIR. Results indicate that for SH-PEG increasing M(m) yields greater stability on AuNPs when measured against displacement by bovine serum albumin (BSA) as a model serum protein. In addition, the binding affinity of BSA to AuNPs is inhibited for SH-PEG conjugated AuNPs, an effect that is enhanced at higher SH-PEG M(m) values.

  10. Quantitative Subtractively Normalized Interfacial Fourier Transform Infrared Reflection Spectroscopy Study of the Adsorption of Adenine on Au(111) Electrodes.

    PubMed

    Prieto, Francisco; Su, Zhangfei; Leitch, J Jay; Rueda, Manuela; Lipkowski, Jacek

    2016-04-26

    Quantitative subtractively normalized interfacial Fourier transform infrared reflection spectroscopy (SNIFTIRS) was used to determine the molecular orientation and identify the metal-molecular interactions responsible for the adsorption of adenine from the bulk electrolyte solution onto the surface of the Au(111) electrode. The recorded p-polarized IR spectra of the adsorbed species were subtracted from the collected s-polarized IR spectra to remove the IR contributions of the vibrational bands of the desorbed molecules that are located within the thin layer cavity of the spectroelectrochemical cell. The intense IR band around 1640 cm(-1), which is assigned to the pyrimidine ring stretching vibrations of the C5-C6 and C6-N10 bonds, and the IR band at 1380 cm(-1), which results from a combination of the ring stretching vibration of the C5-C7 bond and the in-plane CH bending vibration, were selected for the quantitative analysis measurements. The transition dipoles of these bands were evaluated by DFT calculations. Their orientations differed by 85 ± 5°. The tilt angles of adsorbed adenine molecules were calculated from the intensity of these two vibrations at different potentials. The results indicate that the molecular plane is tilted at an angle of 40° with respect to the surface normal of the electrode and rotates by 16° around its normal axis with increasing electrode potential. This orientation results from the chemical interaction between the N10 and gold atoms coupled with the π-π parallel stacking interactions between the adjacent adsorbed molecules. Furthermore, the changes in the molecular plane rotation with the electric field suggests that the N1 atom of adenine must also participate in the interaction between the molecule and metal.

  11. Evaluation of near-infrared reflectance spectroscopy (NIRS) techniques for total and phytate phosphorus of common poultry feed ingredients.

    PubMed

    Tahir, M; Shim, M Y; Ward, N E; Westerhaus, M O; Pesti, G M

    2012-10-01

    The purpose of this study was to determine the feasibility of estimating the total and phytate P content of common poultry feed ingredients by near-infrared reflectance spectroscopy (NIRS). Samples of 8 plant-origin feedstuffs were collected from poultry producers in the USA and Canada during the summer of 2009: corn (133), soybean meal (114), corn distillers dried grains with solubles (DDGS; 89), bakery by-product meal (95), wheat (22), wheat middlings (31), canola meal (21), and wheat shorts (15). The samples were assayed by standard wet chemical techniques for total and phytate P contents. There was considerable variation found in most of the ingredient components. The average values for the laboratory determinations versus NIRS predictions were all within 0.030 for total phosphorus and 0.012 for phytate P. For phytate P, the magnitude of the standard errors of the predictions ranged from 0.009% for soybean meal to 0.012% for canola meal. These values may be sufficiently precise for nutritionists to use the NIRS predictions to estimate how much of the P in their ingredients is not available to the birds. For total P, the magnitude of the standard errors of the predictions ranged from 0.027% for corn DDGS to 0.142% for wheat middlings. In general, total P predictions by NIRS were not generally sufficiently precise for most nutritionists to use in feed formulation. Decision making may be quite easy in using NIRS estimates for the phytate P content of bakery by-product meal [R(2) = 0.89 for predicted = f (determined)] but not for the total P content of soybean meal (R(2) = 0.03). It is concluded that precise estimates of phytate P through NIRS should allow nutritionists for more efficient formulate and mix feed, lowering feed costs and reducing the amount of residual polluting phosphorus in poultry excreta.

  12. Applicability of near-infrared reflectance spectroscopy (NIRS) for determination of crude protein content in cowpea (Vigna unguiculata) leaves

    PubMed Central

    Towett, Erick K; Alex, Merle; Shepherd, Keith D; Polreich, Severin; Aynekulu, Ermias; Maass, Brigitte L

    2013-01-01

    There is uncertainty on how generally applicable near-infrared reflectance spectroscopy (NIRS) calibrations are across genotypes and environments, and this study tests how well a single calibration performs across a wide range of conditions. We also address the optimization of NIRS to perform the analysis of crude protein (CP) content in a variety of cowpea accessions (n = 561) representing genotypic variation as well as grown in a wide range of environmental conditions in Tanzania and Uganda. The samples were submitted to NIRS analysis and a predictive calibration model developed. A modified partial least-squares regression with cross-validation was used to evaluate the models and identify possible spectral outliers. Calibration statistics for CP suggests that NIRS can predict this parameter in a wide range of cowpea leaves from different agro-ecological zones of eastern Africa with high accuracy (R2cal = 0.93; standard error of cross-validation = 0.74). NIRS analysis improved when a calibration set was developed from samples selected to represent the range of spectral variability. We conclude from the present results that this technique is a good alternative to chemical analysis for the determination of CP contents in leaf samples from cowpea in the African context, as one of the main advantages of NIRS is the large number of compounds that can be measured at once in the same sample, thus substantially reducing the cost per analysis. The current model is applicable in predicting the CP content of young cowpea leaves for human nutrition from different agro-ecological zones and genetic materials, as cowpea leaves are one of the popular vegetables in the region. PMID:24804013

  13. Classification and quantification analysis of peach kernel from different origins with near-infrared diffuse reflection spectroscopy

    PubMed Central

    Liu, Wei; Wang, Zhen-Zhong; Qing, Jian-Ping; Li, Hong-Juan; Xiao, Wei

    2014-01-01

    Background: Peach kernels which contain kinds of fatty acids play an important role in the regulation of a variety of physiological and biological functions. Objective: To establish an innovative and rapid diffuse reflectance near-infrared spectroscopy (DR-NIR) analysis method along with chemometric techniques for the qualitative and quantitative determination of a peach kernel. Materials and Methods: Peach kernel samples from nine different origins were analyzed with high-performance liquid chromatography (HPLC) as a reference method. DR-NIR is in the spectral range 1100-2300 nm. Principal component analysis (PCA) and partial least squares regression (PLSR) algorithm were applied to obtain prediction models, The Savitzky-Golay derivative and first derivative were adopted for the spectral pre-processing, PCA was applied to classify the varieties of those samples. For the quantitative calibration, the models of linoleic and oleinic acids were established with the PLSR algorithm and the optimal principal component (PC) numbers were selected with leave-one-out (LOO) cross-validation. The established models were evaluated with the root mean square error of deviation (RMSED) and corresponding correlation coefficients (R2). Results: The PCA results of DR-NIR spectra yield clear classification of the two varieties of peach kernel. PLSR had a better predictive ability. The correlation coefficients of the two calibration models were above 0.99, and the RMSED of linoleic and oleinic acids were 1.266% and 1.412%, respectively. Conclusion: The DR-NIR combined with PCA and PLSR algorithm could be used efficiently to identify and quantify peach kernels and also help to solve variety problem. PMID:25422544

  14. Applicability of near-infrared reflectance spectroscopy (NIRS) for determination of crude protein content in cowpea (Vigna unguiculata) leaves.

    PubMed

    Towett, Erick K; Alex, Merle; Shepherd, Keith D; Polreich, Severin; Aynekulu, Ermias; Maass, Brigitte L

    2013-01-01

    There is uncertainty on how generally applicable near-infrared reflectance spectroscopy (NIRS) calibrations are across genotypes and environments, and this study tests how well a single calibration performs across a wide range of conditions. We also address the optimization of NIRS to perform the analysis of crude protein (CP) content in a variety of cowpea accessions (n = 561) representing genotypic variation as well as grown in a wide range of environmental conditions in Tanzania and Uganda. The samples were submitted to NIRS analysis and a predictive calibration model developed. A modified partial least-squares regression with cross-validation was used to evaluate the models and identify possible spectral outliers. Calibration statistics for CP suggests that NIRS can predict this parameter in a wide range of cowpea leaves from different agro-ecological zones of eastern Africa with high accuracy (R (2)cal = 0.93; standard error of cross-validation = 0.74). NIRS analysis improved when a calibration set was developed from samples selected to represent the range of spectral variability. We conclude from the present results that this technique is a good alternative to chemical analysis for the determination of CP contents in leaf samples from cowpea in the African context, as one of the main advantages of NIRS is the large number of compounds that can be measured at once in the same sample, thus substantially reducing the cost per analysis. The current model is applicable in predicting the CP content of young cowpea leaves for human nutrition from different agro-ecological zones and genetic materials, as cowpea leaves are one of the popular vegetables in the region.

  15. Attenuated total reflection fourier transform infrared spectroscopy towards disclosing mechanism of bacterial adhesion on thermally stabilized titanium nano-interfaces.

    PubMed

    Gopal, Judy; Chun, Sechul; Doble, Mukesh

    2016-08-01

    Titanium is widely used as medical implant material and as condenser material in the nuclear industry where its integrity is questioned due to its susceptibility to bacterial adhesion. A systematic investigation on the influence of thermally (50-800 °C) stabilized titanium (TS-Ti) nano oxide towards bacterial adhesion was carried out. The results showed that below 350 °C significant bacterio-phobicity was observed, while above 500 °C significant affinity towards bacterial cells was recorded. Conventional characterization tools such as HR-TEM and XRD did not provide much insight on the changes occurring on the oxide film with heat treatment, however, attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) of the surface showed significant changes in the spectral pattern as a function of increasing heat treatment. It was observed that elevated OH, N-H and C=O groups and rutile titania on the TS-Ti oxide films led to higher affinity for bacterial adhesion. On the other hand low temperature TS-Ti nanooxide films (<350 °C) showed high C-H groups and decreased OH groups on their surface, which possibly contributed towards their bacterio-phobicity. The TS-Ti nanooxide film grown at 50 °C was observed to be the most efficient anti-bacterial adhesion interface, while the 800 °C interface was the one showing highest affinity towards bacterial adhesion. This study confirms the successful application of ATR-FTIR technique for nano-oxide film characterization and towards understanding the variations in bacterial interaction of such nano interfaces. PMID:27412653

  16. Simultaneous monitoring of curing shrinkage and degree of cure of thermosets by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy.

    PubMed

    Fernàndez-Francos, Xavier; Kazarian, Sergei G; Ramis, Xavier; Serra, Àngels

    2013-12-01

    We present a novel methodology to simultaneously monitor of the degree of cure and curing shrinkage of thermosetting formulations. This methodology is based on the observation of changes in the infrared absorption of reactive functional groups and the groups used as a standard reference for normalization. While the optical path length is exact and controlled in transmission infrared spectroscopy, in attenuated total reflection Fourier transform infrared (ATR FT-IR), the exact determination of volume changes requires the measurement of the refractive indices of the studied system throughout the curing process or at least an indirect parallel measurement of this property. The methodology presented here allows one to achieve quantitative measurements of the degree of cure and shrinkage for thermosets using in situ ATR FT-IR spectroscopy.

  17. [Methods of analyzing soybean meal adulteration in fish meal based on visible and near infrared reflectance spectroscopy].

    PubMed

    Shi, Guang-Tao; Han, Lu-Jia; Yang, Zeng-Ling; Liu, Xian

    2009-02-01

    The present study investigated the feasibility of visible and near infrared reflectance spectroscopy (NIRS) method for the detection of fish meal adulteration with vegetable meal. Here the authors collected fish meal and soybean meal (representative vegetable meal) which were common used in our country. Fish meal was adulterated with different proportion of soybean meal and then the doping test samples were prepared. Qualitative discriminant analysis and quantitative analysis were studied with representative fish meal adulterated with soybean meal. Two hundred and six calibration samples and 103 validation samples were used in the qualitative discriminant analysis. The effects of different spectrum pre-treatment methods and spectrum regions were considered when the qualitative discriminant analysis model was established. Based on the smallest standard error of cross validation (SECV) and the correct rate, the spectrum region of visible and NIR was chosen as the best region. The eventually established pre-treatment methods were the standard multi-scatter correction (Std MSC) combined with the second derivative (2, 4, 4, 1). Then the independent external validation set was used to test the model, and there was no false positive samples and false negative samples. The correct discriminant rate was 96.12%. In quantitative analysis, 130 fish meal samples adulterated with soybean meal were used as calibration set. The calibration model was established by partial least squares (PLS). Furthermore, the effect of different spectrum pre-treatment methods and the spectrum region were considered. The results showed that the best pre-treatment method was the standard normalized variate (SNV) combined with the second derivative (2, 4, 4, 1). The coefficient of determination (R2) and the standard errors of calibration (SEC) were 0.989 0 and 1.539 0 respectively between the predictive value and the actual value. Sixty five fish meal samples adulterated with soybean meal were used

  18. An Introductory Infrared Spectroscopy Experiment.

    ERIC Educational Resources Information Center

    Hess, Kenneth R.; Smith, Wendy D.; Thomsen, Marcus W.; Yoder, Claude H.

    1995-01-01

    Describes a project designed to introduce infrared spectroscopy as a structure-determination technique. Students are introduced to infrared spectroscopy fundamentals then try to determine the identity of an unknown liquid from its infrared spectrum and molecular weight. The project demonstrates that only rarely can the identity of even simple…

  19. Cartilage analysis by reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Laun, T.; Muenzer, M.; Wenzel, U.; Princz, S.; Hessling, M.

    2015-07-01

    A cartilage bioreactor with analytical functions for cartilage quality monitoring is being developed. For determining cartilage composition, reflection spectroscopy in the visible (VIS) and near infrared (NIR) spectral region is evaluated. Main goal is the determination of the most abundant cartilage compounds water, collagen I and collagen II. Therefore VIS and NIR reflection spectra of different cartilage samples of cow, pig and lamb are recorded. Due to missing analytical instrumentation for identifying the cartilage composition of these samples, typical literature concentration values are used for the development of chemometric models. In spite of these limitations the chemometric models provide good cross correlation results for the prediction of collagen I and II and water concentration based on the visible and the NIR reflection spectra.

  20. Identification of residues by infrared spectroscopy

    SciTech Connect

    Barber, T.E.; Ayala, N.L.; Jin, Hong; Drumheller, C.T.

    1997-12-31

    Mid-infrared spectroscopy of surfaces can be a very powerful technique for the qualitative and quantitative analysis of surface residues. The goal of this work was to study the application of diffuse reflectance mid-infrared spectroscopy to the identification of pesticide, herbicide, and explosive residues on surfaces. A field portable diffuse reflectance spectrometer was used to collect the mid-infrared spectra of clean surfaces and contaminated surfaces. These spectra were used as calibration sets to develop automated data analysis to classify or to identify residues on samples. In this presentation, the instrumentation and data process algorithms will be discussed.

  1. Sensing cocaine in saliva with attenuated total reflection infrared (ATR-IR) spectroscopy combined with a one-step extraction method

    NASA Astrophysics Data System (ADS)

    Hans, Kerstin M.-C.; Gianella, Michele; Sigrist, Markus W.

    2012-03-01

    On-site drug tests have gained importance, e.g., for protecting the society from impaired drivers. Since today's drug tests are majorly only positive/negative, there is a great need for a reliable, portable and preferentially quantitative drug test. In the project IrSens we aim to bridge this gap with the development of an optical sensor platform based on infrared spectroscopy and focus on cocaine detection in saliva. We combine a one-step extraction method, a sample drying technique and infrared attenuated total reflection (ATR) spectroscopy. As a first step we have developed an extraction technique that allows us to extract cocaine from saliva to an almost infrared-transparent solvent and to record ATR spectra with a commercially available Fourier Transform-infrared spectrometer. To the best of our knowledge this is the first time that such a simple and easy-to-use one-step extraction method is used to transfer cocaine from saliva into an organic solvent and detect it quantitatively. With this new method we are able to reach a current limit of detection around 10 μg/ml. This new extraction method could also be applied to waste water monitoring and controlling caffeine content in beverages.

  2. Characterization of Xenorhabdus and Photorhabdus bacteria by Fourier transform mid-infrared spectroscopy with attenuated total reflection (FT-IR/ATR).

    PubMed

    San-Blas, Ernesto; Cubillán, Néstor; Guerra, Mayamarú; Portillo, Edgar; Esteves, Iván

    2012-07-01

    The use of Fourier transform mid-infrared spectroscopy with attenuated total reflection for characterizing entomopathogenic bacteria from genera Xenorhabdus and Photorhabdus is evaluated for the first time. The resulting spectra of Xenorhabdus poinarii and Photorhabdus luminiscens were compared with the spectrum of Escherichia coli samples. The absorption spectra generated by the bacteria samples, were very different at the region below 1400cm(-1) which represents the stretching vibrations of phosphate and carbohydrates. Star diagrams of the fingerprint section of nematodes spectra (between 1,350 and 1,650 cm(-1)) for separation between spectra was used and showed to be a useful tool for classification purposes.

  3. Surface-Enhanced Infrared Spectroscopy and Neutron Reflectivity Studies of Ubiquinone in Hybrid Bilayer Membranes under Potential Control.

    PubMed

    Quirk, Amanda; Lardner, Michael J; Tun, Zin; Burgess, Ian J

    2016-03-01

    Surface-enhanced infrared adsorption spectroscopy (SEIRAS) and neutron reflectometry (NR) were employed to characterize ubiquinone (UQ) containing hybrid bilayer membranes. The biomimetic membrane was prepared by fusing phospholipid vesicles on a hydrophobic octadecanethiol monolayer self-assembled on a thin gold film. Using SEIRAS, the assembly of the membrane is monitored in situ. The presence of ubiquinone is verified by the characteristic carbonyl peaks from the quinone ester. A well-ordered distal lipid leaflet results from fusion of vesicles with and without the addition of ubiquinone. With applied potential, the hybrid bilayer membrane in the absence of UQ behaves in the same way as previously reported solid supported phospholipid membranes. When ubiquinone is incorporated in the membrane, electric field induced changes in the distal leaflet are suppressed. Changes in the infrared vibrations of the ubiquinone due to applied potential indicate the head groups are located in both polar and nonpolar environments. The spectroscopic data reveal that the isoprenoid unit of the ubiquinone is likely lying in the midplane of the lipid bilayer while the head has some freedom to move within the hydrophobic core. The SEIRAS experiments show redox behavior of UQ incorporated in a model lipid membrane that are otherwise inaccessible with traditional electrochemistry techniques. PMID:26867110

  4. Transient infrared transmission spectroscopy

    SciTech Connect

    Jones, R.W.; McClelland, J.F. )

    1990-10-15

    Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error or prediction of only 0.87 mol % is demonstrated.

  5. Transient infrared transmission spectroscopy.

    PubMed

    Jones, R W; McClelland, J F

    1990-10-15

    Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error of prediction of only 0.87 mol % is demonstrated.

  6. Measurement of sugar content of watermelon using near-infrared reflectance spectroscopy in comparison with dielectric property

    NASA Astrophysics Data System (ADS)

    Tao, Xuemei; Bao, Yidan

    2006-09-01

    The sugar content of watermelon is important to its taste thus influences the market. It's difficult to know whether the melon is sweet or not for consumers. We tried to develop a convenient meter to determine the sugar of watermelon. The first objective of this paper was to demonstrate the feasibility of using a near-infrared reflectance spectrometer (NIRS) to investigate the relationship between sugar content of watermelon and absorption spectra. The NIRS reflectance of nondestructive watermelon was measured with a Visible/NIR spectrophotometer in 325-1075nm range. The sugar content of watermelon was obtained with a handhold sugar content meter. The second objective was to measure the watermelon's dielectric property, such as dielectric resistance, capacitance, quality factor and dielectric loss. A digital electric bridge instrument was used to get the dielectric property. The experimental results show that they were related to watermelon's sugar content. A comparison between the two methods was made in the paper. The model derived from NIRS reflection is useful for class identification of Zaochun Hongyu watermelon though it's not quite accurate in sweetness prediction (the max. deviation is 0.7). Electric property bears little relation to sugar content of watermelon at this experiment and it couldn't be used as non-destructive inspection method.

  7. Infrared heterodyne spectroscopy in astronomy

    NASA Technical Reports Server (NTRS)

    Betz, A.

    1980-01-01

    A heterodyne spectrometer was constructed and applied to problems in infrared astronomical spectroscopy. The instrument offers distinct observational advantages for the detection and analysis of individual spectral lines at Doppler-limited resolution. Observations of carbon dioxide in planetary atmospheres and ammonia in circumstellar environments demonstrate the substantial role that infrared heterodyne techniques will play in the astronomical spectroscopy of the future.

  8. Identification of fungal phytopathogens using Fourier transform infrared-attenuated total reflection spectroscopy and advanced statistical methods

    NASA Astrophysics Data System (ADS)

    Salman, Ahmad; Lapidot, Itshak; Pomerantz, Ami; Tsror, Leah; Shufan, Elad; Moreh, Raymond; Mordechai, Shaul; Huleihel, Mahmoud

    2012-01-01

    The early diagnosis of phytopathogens is of a great importance; it could save large economical losses due to crops damaged by fungal diseases, and prevent unnecessary soil fumigation or the use of fungicides and bactericides and thus prevent considerable environmental pollution. In this study, 18 isolates of three different fungi genera were investigated; six isolates of Colletotrichum coccodes, six isolates of Verticillium dahliae and six isolates of Fusarium oxysporum. Our main goal was to differentiate these fungi samples on the level of isolates, based on their infrared absorption spectra obtained using the Fourier transform infrared-attenuated total reflection (FTIR-ATR) sampling technique. Advanced statistical and mathematical methods: principal component analysis (PCA), linear discriminant analysis (LDA), and k-means were applied to the spectra after manipulation. Our results showed significant spectral differences between the various fungi genera examined. The use of k-means enabled classification between the genera with a 94.5% accuracy, whereas the use of PCA [3 principal components (PCs)] and LDA has achieved a 99.7% success rate. However, on the level of isolates, the best differentiation results were obtained using PCA (9 PCs) and LDA for the lower wavenumber region (800-1775 cm-1), with identification success rates of 87%, 85.5%, and 94.5% for Colletotrichum, Fusarium, and Verticillium strains, respectively.

  9. Fully reflective external-cavity setup for quantum-cascade lasers as a local oscillator in mid-infrared wavelength heterodyne spectroscopy.

    PubMed

    Stupar, Dusan; Krieg, Jürgen; Krötz, Peter; Sonnabend, Guido; Sornig, Manuela; Giesen, Thomas F; Schieder, Rudolf

    2008-06-01

    To our knowledge we present the first experiments with a fully reflective external-cavity quantum-cascade laser system at mid-infrared wavelengths for use as a local oscillator in a heterodyne receiver. The performance of the presented setup was investigated using absorption spectroscopy as well as heterodyne techniques. Tunability over approximately 30 cm(-1) at 1130 cm(-1) was demonstrated using a grating spectrometer. A continuous tuning range of 0.28 cm(-1) was verified by observing the spectra of an internally coupled confocal Fabry-Pérot interferometer and the absorption lines of gas phase SO(2). In a second step the output from the system was used as a local oscillator signal for a heterodyne setup. We show that spectral stability and side mode suppression are excellent and that a compact external-cavity quantum-cascade laser system is well suited to be used as a local oscillator in infrared heterodyne spectrometers.

  10. An approach by using near-infrared diffuse reflectance spectroscopy and resin adsorption for the determination of copper, cobalt and nickel ions in dilute solution.

    PubMed

    Sheng, Nan; Cai, Wensheng; Shao, Xueguang

    2009-07-15

    Near-infrared spectroscopy (NIRS) has been proved to be a powerful analytical tool and used in various fields, it is seldom, however, used in the analysis of metal ions in solutions. A method for quantitative determination of metal ions in solution is developed by using resin adsorption and near-infrared diffuse reflectance spectroscopy (NIRDRS). The method makes use of the resin adsorption for gathering the analytes from a dilute solution, and then NIRDRS of the adsorbate is measured. Because both the information of the metal ions and their interaction with the functional group of resin can be reflected in the spectrum, quantitative determination is achieved by using multivariate calibration technique. Taking copper (Cu(2+)), cobalt (Co(2+)) and nickel (Ni(2+)) as the analyzing targets and D401 resin as the adsorbent, partial least squares (PLS) model is built from the NIRDRS of the adsorbates. The results show that the concentrations that can be quantitatively detected are as low as 1.00, 1.98 and 1.00 mg L(-1) for Cu(2+), Co(2+) and Ni(2+), respectively, and the coexistent ions do not influence the determination.

  11. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR FT-IR) Applied to Study the Distribution of Ink Components in Printed Newspapers.

    PubMed

    Gómez, Nuria; Molleda, Cristina; Quintana, Ester; Carbajo, José M; Rodríguez, Alejandro; Villar, Juan C

    2016-09-01

    A new method was developed to study how the oil and cyan pigments of cold-set ink are distributed in newspaper thickness. The methodology involved laboratory printing followed by delamination of the printed paper. The unprinted side, printed side, and resulting layers were analyzed using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR). Three commercial newspapers and black and cyan cold-set inks were chosen for the study. Attenuated total reflection Fourier transform infrared spectroscopy enabled the proportion of oil and cyan pigment on the printed surface and throughout the sheet thickness to be measured. Oil percentage was evaluated as the area increment of the region from 2800 cm(-1) to 3000 cm(-1) The relative amount of cyan pigment was determined as the area of the absorption band at 730 cm(-1) The ink oil was found mainly below half the paper thickness, whereas the pigment was detected at the layers closer to the printed surface, at a depth penetration of less than 15 µm (20% of thickness). Distribution of these two components in paper thickness depended on the type of cold-set ink, the amount of ink transferred, and the newspaper properties. PMID:27129363

  12. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR FT-IR) Applied to Study the Distribution of Ink Components in Printed Newspapers.

    PubMed

    Gómez, Nuria; Molleda, Cristina; Quintana, Ester; Carbajo, José M; Rodríguez, Alejandro; Villar, Juan C

    2016-09-01

    A new method was developed to study how the oil and cyan pigments of cold-set ink are distributed in newspaper thickness. The methodology involved laboratory printing followed by delamination of the printed paper. The unprinted side, printed side, and resulting layers were analyzed using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR). Three commercial newspapers and black and cyan cold-set inks were chosen for the study. Attenuated total reflection Fourier transform infrared spectroscopy enabled the proportion of oil and cyan pigment on the printed surface and throughout the sheet thickness to be measured. Oil percentage was evaluated as the area increment of the region from 2800 cm(-1) to 3000 cm(-1) The relative amount of cyan pigment was determined as the area of the absorption band at 730 cm(-1) The ink oil was found mainly below half the paper thickness, whereas the pigment was detected at the layers closer to the printed surface, at a depth penetration of less than 15 µm (20% of thickness). Distribution of these two components in paper thickness depended on the type of cold-set ink, the amount of ink transferred, and the newspaper properties.

  13. Visible-near-infrared reflectance spectroscopy of volcanic acid-sulfate alteration in Nicaragua: Analogs for early Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, Emma C.; Hynek, Brian M.; Kierein-Young, Kathryn S.; Rogers, K. L.

    2013-10-01

    Acid-sulfate weathering at Nicaraguan hydrothermal sites Cerro Negro, Momotombo, and Telica volcanoes and Hervidores de San Jacinto mudpots was characterized as an analog for similar processes that likely operated on early Mars. In situ mineralogical analyses were conducted with a field portable visible near-infrared spectrometer for comparison to similar Martian data sets. Three classes of alteration minerals were identified: sulfates (gypsum and natroalunite), oxides/hydroxides (hematite and goethite), and phyllosilicates (kaolinite/halloysite, montmorillonite, and saponite), as well as elemental sulfur and hydrated silica phases. Our sites had similar suites of minerals, but frequencies varied with location. The results of this field campaign allow inferences regarding the paleo-environmental conditions that were likely present at similar relic hydrothermal sites identified on Mars. In particular, sulfates and phyllosilicates could have coevolved under hydrothermal conditions at Noctis Labyrinthus as is seen in Nicaragua. Fe/Mg smectites were detected in areas with pH of 3-4. Alunite spectra at Terra Sirenum demonstrated mineral mixing effects on spectroscopy. Mineral mixing can cause uncertainties in spectral identification due to a dominant spectrum, such as iron minerals, masking another or the suppression of weaker bands. When viewed from orbit, our field sites would likely be dominated by hydrated silica and Mars sites, such as one in Syrtis Major, could have a more diverse mineralogy than the data reveal. Concentrated amorphous silica, such as at Gusev crater, can result from acidic fumarolic activity, while Mg sulfates may indicate a lack of reworking by water. This field spectroscopy study helps confirm and provide insight into hydrothermal processes on ancient Mars.

  14. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy: An analytical technique to understand therapeutic responses at the molecular level

    PubMed Central

    Kalmodia, Sushma; Parameswaran, Sowmya; Yang, Wenrong; Barrow, Colin J.; Krishnakumar, Subramanian

    2015-01-01

    Rapid monitoring of the response to treatment in cancer patients is essential to predict the outcome of the therapeutic regimen early in the course of the treatment. The conventional methods are laborious, time-consuming, subjective and lack the ability to study different biomolecules and their interactions, simultaneously. Since; mechanisms of cancer and its response to therapy is dependent on molecular interactions and not on single biomolecules, an assay capable of studying molecular interactions as a whole, is preferred. Fourier Transform Infrared (FTIR) spectroscopy has become a popular technique in the field of cancer therapy with an ability to elucidate molecular interactions. The aim of this study, was to explore the utility of the FTIR technique along with multivariate analysis to understand whether the method has the resolution to identify the differences in the mechanism of therapeutic response. Towards achieving the aim, we utilized the mouse xenograft model of retinoblastoma and nanoparticle mediated targeted therapy. The results indicate that the mechanism underlying the response differed between the treated and untreated group which can be elucidated by unique spectral signatures generated by each group. The study establishes the efficiency of non-invasive, label-free and rapid FTIR method in assessing the interactions of nanoparticles with cellular macromolecules towards monitoring the response to cancer therapeutics. PMID:26568521

  15. Use of Attenuated Total Reflectance Mid-Infrared Spectroscopy for Rapid Prediction of Amino Acids in Chinese Rice Wine.

    PubMed

    Wu, Zhengzong; Xu, Enbo; Long, Jie; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2015-08-01

    The high content of amino acids of Chinese rice wine (CRW), especially essential amino acids makes it a food increasingly demanded by consumers. Rapid detection technique of amino acid content, which is an important quality and function index of CRW, is highly desirable for consumers, producers as well as administrative authorities. In this study, the potential of Fourier transform infrared spectroscopy (FT-IR) as a novel and rapid analytical technique to determine 17 free amino acids in CRW were investigated. Genetic algorithms (GA) and synergy interval partial least squares (SiPLS) were used to select the most efficient spectral variables to improve the prediction precision of the classic partial least squares (PLS) model constructed on the full-spectrum. The results demonstrated that compared with the PLS model using all wavelengths of FT-IR spectra, the prediction precision of model based on the spectral variables selected by GA and SiPLS was significantly improved, especially for arginine and proline. After systemic comparison and discussion, it was found that GA-SiPLS model achieved the best performance, with the correlation coefficient in calibration (R(2) (cal)) higher than 0.80 and the residual predictive deviation higher than 2.00 for all of the free amino acids analyzed in this study. The overall results confirmed that FT-IR combined with efficient variable selection algorithms is a method that may be useful to replace the traditional methods for routine analysis of free amino acids in CRW.

  16. Taurid Compex reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Birlan, M.; Popescu, M.; Nedelcu, A.

    2014-07-01

    The Taurid complex is a massive stream of material in the inner part of the Solar System. Its name is related to the Taurid meteor shower. This complex is characterized by a cluster of objects having low-inclination (i < 12°), large-eccentricity (0.64--0.85) orbits with semimajor axes spanning the range 1.8--2.6 au. The largest body of the Taurid Complex is the comet P/Encke, and this complex contains more than 20 near-Earth asteroids (NEAs). There is an important lack of information concerning the physical parameters of the Taurid complex. The observational campaign for observing NEAs of the Taurid complex was started in 2011 in order to provide valuable spectroscopic data for characterizing the surfaces of the complex members. The paper presents near-infrared spectroscopy using IRTF/SpeX obtained remotely from Paris Observatory and Bucharest Observatory for the following asteroids: (2201) Oljato, (4183) Cuno, (4486) Mithra, (5243) Heracles, (6063) Jason, and (269690) 1996 RG_3. We will present a detailed analysis of these spectra which allows their association with several minerals and laboratory spectra of meteorites.

  17. Application of near-infrared reflectance spectroscopy to the simultaneous prediction of alkaloids and phenolic substances in green tea leaves.

    PubMed

    Schulz, H; Engelhardt, U H; Wegent, A; Drews, H; Lapczynski, S

    1999-12-01

    A near-infrared reflectance spectroscopic (NIRS) method for the prediction of polyphenol and alkaloid compounds in the leaves of green tea [Camellia sinensis (L.) O. Kuntze] was developed. Reference measurements of the individual catechins, gallic acid, caffeine, and theobromine were performed by reversed-phase HPLC. The total polyphenols were determined according to the colorimetric Folin-Ciocalteu assay. Using the partial least-squares algorithm, very good calibration statistics were obtained for the prediction of gallic acid, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, caffeine, and theobromine (R(2) > 0.85) with standard deviation/standard error of cross-validation (SD/SECV) ratio ranging from 2.00 to 6.27. Simultaneously, the dry matter content of the tea leaves can be analyzed very precisely (R(2) = 0.94; SD/SECV = 4.12). Furthermore, it is possible to discriminate tea leaves of different age by principal component analysis on the basis of the received NIR spectra. Prediction of the total polyphenol content is performed with a lower accuracy, which might be due to the lack of specificity in the colorimetric reference method. The study demonstrates that NIRS technology can be successfully applied as a rapid method not only for breeding and cultivation purposes but also to estimate the quality and taste of green tea and to control industrial processes, for example, decaffeination.

  18. Application of near-infrared reflectance spectroscopy to the simultaneous prediction of alkaloids and phenolic substances in green tea leaves.

    PubMed

    Schulz, H; Engelhardt, U H; Wegent, A; Drews, H; Lapczynski, S

    1999-12-01

    A near-infrared reflectance spectroscopic (NIRS) method for the prediction of polyphenol and alkaloid compounds in the leaves of green tea [Camellia sinensis (L.) O. Kuntze] was developed. Reference measurements of the individual catechins, gallic acid, caffeine, and theobromine were performed by reversed-phase HPLC. The total polyphenols were determined according to the colorimetric Folin-Ciocalteu assay. Using the partial least-squares algorithm, very good calibration statistics were obtained for the prediction of gallic acid, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, caffeine, and theobromine (R(2) > 0.85) with standard deviation/standard error of cross-validation (SD/SECV) ratio ranging from 2.00 to 6.27. Simultaneously, the dry matter content of the tea leaves can be analyzed very precisely (R(2) = 0.94; SD/SECV = 4.12). Furthermore, it is possible to discriminate tea leaves of different age by principal component analysis on the basis of the received NIR spectra. Prediction of the total polyphenol content is performed with a lower accuracy, which might be due to the lack of specificity in the colorimetric reference method. The study demonstrates that NIRS technology can be successfully applied as a rapid method not only for breeding and cultivation purposes but also to estimate the quality and taste of green tea and to control industrial processes, for example, decaffeination. PMID:10606573

  19. Simultaneous monitoring of organic acids and sugars in fresh and processed apple juice by Fourier transform infrared-attenuated total reflection spectroscopy.

    PubMed

    Irudayaraj, Joseph; Tewari, Jagdish

    2003-12-01

    A combination of Fourier transform infrared spectroscopy (FT-IR) and chemometrics was used as a screening tool for the determination of sugars and organic acids such as sucrose, glucose, fructose, sorbitol, citric acid, and malic acid in processed commercial and extracted fresh apple juices. Prepared samples of synthetic apple juice in different constituent concentration ranges were scanned by attenuated total reflectance (ATR) accessory and the spectral region in the range between 950 and 1500 cm(-1) was selected for calibration model development using partial least squares (PLS) regression and principal component regression (PCR). The calibration models were successfully validated by high-performance liquid chromatography (HPLC) measurements against several commercial juice varieties as well as juice extracted from different apple varieties to provide an overall R2 correlation of 0.998. The present study demonstrates that Fourier transform infrared spectroscopy could be used for rapid and nondestructive determination of multiple constituents in commercial and fresh apple juices. Results indicate this approach to be a rapid and cost-effective tool for routine monitoring of multiple constituents in a fruit juice production facility.

  20. Structure of collagen adsorbed on a model implant surface resolved by polarization modulation infrared reflection-absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Brand, Izabella; Habecker, Florian; Ahlers, Michael; Klüner, Thorsten

    2015-03-01

    The polarization modulation infrared reflection-absorption spectra of collagen adsorbed on a titania surface and quantum chemical calculations are used to describe components of the amide I mode to the protein structure at a sub-molecular level. In this study, imino acid rich and poor fragments, representing the entire collagen molecule, are taken into account. The amide I mode of the collagen triple helix is composed of three absorption bands which involve: (i) (∼1690 cm-1) the Cdbnd O stretching modes at unhydrated groups, (ii) (1655-1673 cm-1) the Cdbnd O stretching at carbonyl groups at imino acids and glycine forming intramolecular hydrogen bonds with H atoms at both NH2 and, unusual for proteins, CH2 groups at glycine at a neighbouring chain and (iii) (∼1640 cm-1) the Cdbnd O stretching at carbonyl groups forming hydrogen bonds between two, often charged, amino acids as well as hydrogen bonds to water along the entire helix. The IR spectrum of films prepared from diluted solutions (c < 50 μg ml-1) corresponds to solution spectra indicating that native collagen molecules interact with water adsorbed on the titania surface. In films prepared from solutions (c ⩾ 50 μg ml-1) collagen multilayers are formed. The amide I mode is blue-shifted by 18 cm-1, indicating that intramolecular hydrogen bonds at imino acid rich fragments are weakened. Simultaneous red-shift of the amide A mode implies that the strength of hydrogen bonds at the imino acid poor fragments increases. Theoretically predicted distortion of the collagen structure upon adsorption on the titania surface is experimentally confirmed.

  1. Using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) to study the molecular conformation of parchment artifacts in different macroscopic states.

    PubMed

    Gonzalez, Lee; Wade, Matthew; Bell, Nancy; Thomas, Kate; Wess, Tim

    2013-02-01

    Maintaining appropriate temperatures and relative humidity is considered essential to extending the useful life of parchment artifacts. Although the relationship between environmental factors and changes to the physical state of artifacts is reasonably understood, an improved understanding of the relationship between the molecular conformation and changes to the macroscopic condition of parchment is needed to optimize environmental conditions. Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FT-IR) analysis, the conformation of the molecular structure in selected parchment samples with specific macroscopic conditions, typically discoloration and planar deformations (e.g., cockling and tearing), have been made. The results of this investigation showed that the Fourier transform infrared signal differs for parchment samples exhibiting different macroscopic conditions. In areas exhibiting planar deformation, a change in the Fourier Transform Infrared signal was observed that indicates unfolding of the molecular conformation. In comparison, the discolored samples showed a change in molecular conformation that indicates a chemical change within the collagen molecular structure. This paper discusses the possible causal associations and implications of these findings for the conservation and preservation of parchment artifacts.

  2. Infrared spectroscopy in biomedical diagnostics

    NASA Astrophysics Data System (ADS)

    Afanasyeva, Natalia I.; Kolyakov, Sergei F.; Letokhov, Vladilen S.; Artioushenko, Vjacheslav G.; Golovkina, Viktoriya N.

    1998-01-01

    Fiberoptic evanescent wave Fourier transform infrared (FEW- FTIR) spectroscopy using fiberoptic sensors operated in the attenuated total reflection (ATR) regime in the middle infrared (IR) region of the spectrum (850 - 1850 cm-1) has recently found application in the diagnostics of tissues. The method is suitable for noninvasive and rapid (seconds) direct measurements of the spectra of normal and pathological tissues in vitro, ex vivo and in vivo. The aim of our studies is the express testing of various tumor tissues at the early stages of their development. The method is expected to be further developed for endoscopic and biopsy applications. We measured in vivo the skin normal and malignant tissues on surface (directly on patients) in various cases of basaloma, melanoma and nevus. The experiments were performed in the operating room for measurements of skin in the depth (under/in the layers of epidermis), human breast, stomach, lung, kidney tissues. The breast and skin tissues at different stages of tumor or cancer were distinguished very clearly in spectra of amide, side cyclic and noncyclic hydrogen bonded fragments of amino acid residuals, phosphate groups and sugars. Computer monitoring is being developed for diagnostics.

  3. Application of micro-attenuated total reflectance Fourier transform infrared spectroscopy to ink examination in signatures written with ballpoint pen on questioned documents.

    PubMed

    Nam, Yun Sik; Park, Jin Sook; Lee, Yeonhee; Lee, Kang-Bong

    2014-05-01

    Questioned documents examined in a forensic laboratory sometimes contain signatures written with ballpoint pen inks; these signatures were examined to assess the feasibility of micro-attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy as a forensic tool. Micro-ATR FTIR spectra for signatures written with 63 ballpoint pens available commercially in Korea were obtained and used to construct an FTIR spectral database. A library-searching program was utilized to identify the manufacturer, blend, and model of each black ballpoint pen ink based upon their FTIR peak intensities, positions, and patterns in the spectral database. This FTIR technique was also successfully used in determining the sequence of homogeneous line intersections from the crossing lines of two ballpoint pen signatures. We have demonstrated with a set of sample documents that micro-ATR FTIR is a viable nondestructive analytical method that can be used to identify the origin of the ballpoint pen ink used to mark signatures. PMID:24661236

  4. Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectroscopy.

    PubMed

    Saucedo-Hernández, Yanelis; Lerma-García, María Jesús; Herrero-Martínez, José Manuel; Ramis-Ramos, Guillermo; Jorge-Rodríguez, Elisa; Simí-Alfonso, Ernesto F

    2011-04-27

    Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species and C. moschata varieties was achieved. The proposed method was straightforward and quick and can be easily implemented. Quality control of pumpkin seed oils is important because Cucurbita species and genetic variety are both related to the pharmaceutical properties of the oils.

  5. Breeds and muscle types modulate performance of near-infrared reflectance spectroscopy to predict the fatty acid composition of bovine meat.

    PubMed

    Mourot, B P; Gruffat, D; Durand, D; Chesneau, G; Mairesse, G; Andueza, D

    2015-01-01

    This study aims to assess near-infrared reflectance spectroscopy feasibility for predicting beef fatty acid (FA) composition. Experimental scheme included four breeds (Angus, Blond d'Aquitaine, Charolais, Limousin) and three muscles, Longissimus thoracis (LT), Rectus abdominis (RA), Semitendinosus (ST). The results showed that 1) increasing FA content variability with several breeds increased calibration model reliability (R(2)CV>0.86) for the major individual and groups of FA unless polyunsaturated FAs, 2) Longissimus thoracis FAs were better predicted than RA FAs while no ST FAs were correctly predicted (R(2)CV<0.71). This difference could be explained by FA content, FA variability or specific muscle physico-chemical characteristics.

  6. Determination of uronic acids in isolated hemicelluloses from kenaf using diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and the curve-fitting deconvolution method.

    PubMed

    Batsoulis, A N; Nacos, M K; Pappas, C S; Tarantilis, P A; Mavromoustakos, T; Polissiou, M G

    2004-02-01

    Hemicellulose samples were isolated from kenaf (Hibiscus cannabinus L.). Hemicellulosic fractions usually contain a variable percentage of uronic acids. The uronic acid content (expressed in polygalacturonic acid) of the isolated hemicelluloses was determined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and the curve-fitting deconvolution method. A linear relationship between uronic acids content and the sum of the peak areas at 1745, 1715, and 1600 cm(-1) was established with a high correlation coefficient (0.98). The deconvolution analysis using the curve-fitting method allowed the elimination of spectral interferences from other cell wall components. The above method was compared with an established spectrophotometric method and was found equivalent for accuracy and repeatability (t-test, F-test). This method is applicable in analysis of natural or synthetic mixtures and/or crude substances. The proposed method is simple, rapid, and nondestructive for the samples.

  7. Microscopic emission and reflectance thermal infrared spectroscopy: instrumentation for quantitative in situ mineralogy of complex planetary surfaces.

    PubMed

    Edwards, C S; Christensen, P R

    2013-04-10

    The diversity of investigations of planetary surfaces, especially Mars, using in situ instrumentation over the last decade is unprecedented in the exploration history of our solar system. The style of instrumentation that landed spacecraft can support is dependent on several parameters, including mass, power consumption, instrument complexity, cost, and desired measurement type (e.g., chemistry, mineralogy, petrology, morphology, etc.), all of which must be evaluated when deciding an appropriate spacecraft payload. We present a laboratory technique for a microscopic emission and reflectance spectrometer for the analysis of martian analog materials as a strong candidate for the next generation of in situ instruments designed to definitively assess sample mineralogy and petrology while preserving geologic context. We discuss the instrument capabilities, signal and noise, and overall system performance. We evaluate the ability of this instrument to quantitatively determine sample mineralogy, including bulk mineral abundances. This capability is greatly enhanced. Whereas the number of mineral components observed from existing emission spectrometers is high (often >5 to 10 depending on the number of accessory and alteration phases present), the number of mineral components at any microscopic measurement spot is low (typically <2 to 3). Since this style of instrument is based on a long heritage of thermal infrared emission spectrometers sent to orbit (the thermal emission spectrometer), sent to planetary surfaces [the mini-thermal emission spectrometers (mini-TES)], and evaluated in laboratory environments (e.g., the Arizona State University emission spectrometer laboratory), direct comparisons to existing data are uniquely possible with this style of instrument. The ability to obtain bulk mineralogy and atmospheric data, much in the same manner as the mini-TESs, is of significant additional value and maintains the long history of atmospheric monitoring for Mars

  8. Microscopic emission and reflectance thermal infrared spectroscopy: instrumentation for quantitative in situ mineralogy of complex planetary surfaces.

    PubMed

    Edwards, C S; Christensen, P R

    2013-04-10

    The diversity of investigations of planetary surfaces, especially Mars, using in situ instrumentation over the last decade is unprecedented in the exploration history of our solar system. The style of instrumentation that landed spacecraft can support is dependent on several parameters, including mass, power consumption, instrument complexity, cost, and desired measurement type (e.g., chemistry, mineralogy, petrology, morphology, etc.), all of which must be evaluated when deciding an appropriate spacecraft payload. We present a laboratory technique for a microscopic emission and reflectance spectrometer for the analysis of martian analog materials as a strong candidate for the next generation of in situ instruments designed to definitively assess sample mineralogy and petrology while preserving geologic context. We discuss the instrument capabilities, signal and noise, and overall system performance. We evaluate the ability of this instrument to quantitatively determine sample mineralogy, including bulk mineral abundances. This capability is greatly enhanced. Whereas the number of mineral components observed from existing emission spectrometers is high (often >5 to 10 depending on the number of accessory and alteration phases present), the number of mineral components at any microscopic measurement spot is low (typically <2 to 3). Since this style of instrument is based on a long heritage of thermal infrared emission spectrometers sent to orbit (the thermal emission spectrometer), sent to planetary surfaces [the mini-thermal emission spectrometers (mini-TES)], and evaluated in laboratory environments (e.g., the Arizona State University emission spectrometer laboratory), direct comparisons to existing data are uniquely possible with this style of instrument. The ability to obtain bulk mineralogy and atmospheric data, much in the same manner as the mini-TESs, is of significant additional value and maintains the long history of atmospheric monitoring for Mars

  9. Detection limits for blood on four fabric types using infrared diffuse reflection spectroscopy in mid- and near-infrared spectral windows.

    PubMed

    DeJong, Stephanie A; Lu, Zhenyu; Cassidy, Brianna M; O'Brien, Wayne L; Morgan, Stephen L; Myrick, Michael L

    2015-09-01

    Detection limits (DL) for blood on four fabric types were estimated for calibrations derived using partial least squares regression applied to infrared (IR) diffuse reflection spectra. Samples were prepared by dip-coating acrylic, cotton, nylon, and polyester fabrics from solutions of diluted rat blood. While DLs often appear in terms of dilution factor in the forensic community, mass percentage, coverage (mass per unit area), or film thickness are often more relevant when comparing experimental methods. These alternate DL units are related to one another and presented here. The best IR diffuse reflection DLs for blood on acrylic and cotton fabrics were in the mid-IR spectral window corresponding to the protein Amide I/II absorption bands. These DLs were dilution by a factor of 2300 (0.019% w/w blood solids) for acrylic and a factor of 610 (0.055% w/w blood solids) for cotton. The best DL for blood on polyester was found in the mid-IR spectral window corresponding to the protein Amide A absorption band at dilution by a factor of 900 (0.034% w/w blood solids). Because of the similarity between the IR spectra of blood solids and nylon fabrics, no satisfactory IR DLs were determined for the calibration of blood on nylon. We compare our values to DLs reported for blood detection using the standard luminol method. The most commonly reported luminol DLs are of the order of 1000-fold dilution, which we estimate are a factor of 2-7 lower than our reported IR DLs on a coverage basis.

  10. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    SciTech Connect

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-15

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  11. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes.

    PubMed

    Wiesinger, R; Schade, U; Kleber, Ch; Schreiner, M

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  12. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    NASA Astrophysics Data System (ADS)

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  13. Simultaneous probing of bulk liquid phase and catalytic gas-liquid-solid interface under working conditions using attenuated total reflection infrared spectroscopy

    SciTech Connect

    Meemken, Fabian; Müller, Philipp; Hungerbühler, Konrad; Baiker, Alfons

    2014-08-15

    Design and performance of a reactor set-up for attenuated total reflection infrared (ATR-IR) spectroscopy suitable for simultaneous reaction monitoring of bulk liquid and catalytic solid-liquid-gas interfaces under working conditions are presented. As advancement of in situ spectroscopy an operando methodology for gas-liquid-solid reaction monitoring was developed that simultaneously combines catalytic activity and molecular level detection at the catalytically active site of the same sample. Semi-batch reactor conditions are achieved with the analytical set-up by implementing the ATR-IR flow-through cell in a recycle reactor system and integrating a specifically designed gas feeding system coupled with a bubble trap. By the use of only one spectrometer the design of the new ATR-IR reactor cell allows for simultaneous detection of the bulk liquid and the catalytic interface during the working reaction. Holding two internal reflection elements (IRE) the sample compartments of the horizontally movable cell are consecutively flushed with reaction solution and pneumatically actuated, rapid switching of the cell (<1 s) enables to quasi simultaneously follow the heterogeneously catalysed reaction at the catalytic interface on a catalyst-coated IRE and in the bulk liquid on a blank IRE. For a complex heterogeneous reaction, the asymmetric hydrogenation of 2,2,2-trifluoroacetophenone on chirally modified Pt catalyst the elucidation of catalytic activity/enantioselectivity coupled with simultaneous monitoring of the catalytic solid-liquid-gas interface is shown. Both catalytic activity and enantioselectivity are strongly dependent on the experimental conditions. The opportunity to gain improved understanding by coupling measurements of catalytic performance and spectroscopic detection is presented. In addition, the applicability of modulation excitation spectroscopy and phase-sensitive detection are demonstrated.

  14. A simple, sensitive and non-destructive technique for characterizing bovine dental enamel erosion: attenuated total reflection Fourier transform infrared spectroscopy

    PubMed Central

    Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub

    2016-01-01

    Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion. PMID:27025266

  15. A simple, sensitive and non-destructive technique for characterizing bovine dental enamel erosion: attenuated total reflection Fourier transform infrared spectroscopy.

    PubMed

    Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub

    2016-03-30

    Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion.

  16. A simple, sensitive and non-destructive technique for characterizing bovine dental enamel erosion: attenuated total reflection Fourier transform infrared spectroscopy.

    PubMed

    Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub

    2016-03-01

    Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (P<0.001). Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR-FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion. PMID:27025266

  17. Development of a system for classification of pork loins for tenderness using visible and near-infrared reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boneless pork loins (n = 901) were evaluated either on the loin boning and trimming line of large-scale commercial plants (n = 465) or at the U.S. Meat Animal Research Center abattoir (n = 436). Exposed LM on the ventral side of boneless loins was evaluated with visible and near-infrared spectrosco...

  18. Direct and simultaneous quantification of tannin mean degree of polymerization and percentage of galloylation in grape seeds using diffuse reflectance fourier transform-infrared spectroscopy.

    PubMed

    Pappas, Christos; Kyraleou, Maria; Voskidi, Eleni; Kotseridis, Yorgos; Taranilis, Petros A; Kallithraka, Stamatina

    2015-02-01

    The direct and simultaneous quantitative determination of the mean degree of polymerization (mDP) and the degree of galloylation (%G) in grape seeds were quantified using diffuse reflectance infrared Fourier transform spectroscopy and partial least squares (PLS). The results were compared with those obtained using the conventional analysis employing phloroglucinolysis as pretreatment followed by high performance liquid chromatography-UV and mass spectrometry detection. Infrared spectra were recorded in solid state samples after freeze drying. The 2nd derivative of the 1832 to 1416 and 918 to 739 cm(-1) spectral regions for the quantification of mDP, the 2nd derivative of the 1813 to 607 cm(-1) spectral region for the degree of %G determination and PLS regression were used. The determination coefficients (R(2) ) of mDP and %G were 0.99 and 0.98, respectively. The corresponding values of the root-mean-square error of calibration were found 0.506 and 0.692, the root-mean-square error of cross validation 0.811 and 0.921, and the root-mean-square error of prediction 0.612 and 0.801. The proposed method in comparison with the conventional method is simpler, less time consuming, more economical, and requires reduced quantities of chemical reagents and fewer sample pretreatment steps. It could be a starting point for the design of more specific models according to the requirements of the wineries. PMID:25588697

  19. Direct and simultaneous quantification of tannin mean degree of polymerization and percentage of galloylation in grape seeds using diffuse reflectance fourier transform-infrared spectroscopy.

    PubMed

    Pappas, Christos; Kyraleou, Maria; Voskidi, Eleni; Kotseridis, Yorgos; Taranilis, Petros A; Kallithraka, Stamatina

    2015-02-01

    The direct and simultaneous quantitative determination of the mean degree of polymerization (mDP) and the degree of galloylation (%G) in grape seeds were quantified using diffuse reflectance infrared Fourier transform spectroscopy and partial least squares (PLS). The results were compared with those obtained using the conventional analysis employing phloroglucinolysis as pretreatment followed by high performance liquid chromatography-UV and mass spectrometry detection. Infrared spectra were recorded in solid state samples after freeze drying. The 2nd derivative of the 1832 to 1416 and 918 to 739 cm(-1) spectral regions for the quantification of mDP, the 2nd derivative of the 1813 to 607 cm(-1) spectral region for the degree of %G determination and PLS regression were used. The determination coefficients (R(2) ) of mDP and %G were 0.99 and 0.98, respectively. The corresponding values of the root-mean-square error of calibration were found 0.506 and 0.692, the root-mean-square error of cross validation 0.811 and 0.921, and the root-mean-square error of prediction 0.612 and 0.801. The proposed method in comparison with the conventional method is simpler, less time consuming, more economical, and requires reduced quantities of chemical reagents and fewer sample pretreatment steps. It could be a starting point for the design of more specific models according to the requirements of the wineries.

  20. Mid-infrared attenuated total reflection spectroscopy of human stratum corneum using a silver halide fiber probe of square cross-section and adhesive tape stripping

    NASA Astrophysics Data System (ADS)

    Heise, H. M.; Küpper, L.; Butvina, L. N.

    2003-12-01

    Mid-infrared fiber probes allow an extended use of attenuated total reflection (ATR) measurements for topical in vivo skin analysis, which were otherwise not possible with conventional sample compartment accessories. Evanescent wave spectroscopy using a flexible fiber-optic probe from silver halide fibers of square cross-section was employed for stratum corneum characterization and keratinocyte quantification on adhesive tapes. Such a method of quantifying the amount of keratin, which can be repetitively removed from the skin surface by adhesive tape application, is essential for the study of substances topically applied and penetrating into the horny layer. For calibration, the weight of keratinocytes was determined using an ultramicro-balance. Best results were obtained with difference spectroscopy and the evaluation of the amide I absorption band intensity (correlation coefficient r=0.983). Lowest amounts per cm 2 were reached for the range down to 5 μg/cm 2. The heterogeneity in the surface density of keratinocytes clinging to the tape was investigated by microscopy, and the thickness of some individual keratinocytes was tested by ATR-microspectroscopy and atomic force microscopy.

  1. Use of near-infrared reflectance spectroscopy for shelf-life discrimination of green asparagus stored in a cool room under controlled atmosphere.

    PubMed

    Sánchez, María-Teresa; Pérez-Marín, Dolores; Flores-Rojas, Katherine; Guerrero, José-Emilio; Garrido-Varo, Ana

    2009-04-30

    This study sought to evaluate the ability of near-infrared reflectance spectroscopy (NIRS) to classify intact green asparagus, in refrigerated storage under controlled atmosphere, by storage time and post-harvest treatments applied. A total of 468 green asparagus (Asparagus officinalis, L., cultivar UC-157) were sampled after 7, 14, 21 and 28 days of refrigerated storage (2 degrees C, 95% R.H.) under three controlled atmosphere (CA) treatments: air (21 kPa O(2)+0.3 kPa CO(2)), CA(1) (5 kPa O(2)+5 kPa CO(2)) and CA(2) (10 kPa O(2)+10kPa CO(2)). Two commercially available spectrophotometers were evaluated for this purpose: a scanning monochromator (SM) of 400-2500 nm and a combination of diode array and scanning monochromator (DASM) of 350-2500 nm. Models developed using partial least squares 2-discriminant analysis (PLS2-DA) correctly classified between 81-100% of samples by post-harvest storage time, depending on the instrument used. Using similar models, the DASM instrument correctly classified 85% of samples by post-harvest treatment, compared with 72% using the SM. These results confirmed that NIR spectroscopy, coupled with the use of chemometric techniques, provides a reliable, accurate method of predicting the shelf-life of asparagus under different storage conditions and as a function of post-harvest treatment applied; the method can be readily applied at industrial level.

  2. Use of near-infrared reflectance spectroscopy for shelf-life discrimination of green asparagus stored in a cool room under controlled atmosphere.

    PubMed

    Sánchez, María-Teresa; Pérez-Marín, Dolores; Flores-Rojas, Katherine; Guerrero, José-Emilio; Garrido-Varo, Ana

    2009-04-30

    This study sought to evaluate the ability of near-infrared reflectance spectroscopy (NIRS) to classify intact green asparagus, in refrigerated storage under controlled atmosphere, by storage time and post-harvest treatments applied. A total of 468 green asparagus (Asparagus officinalis, L., cultivar UC-157) were sampled after 7, 14, 21 and 28 days of refrigerated storage (2 degrees C, 95% R.H.) under three controlled atmosphere (CA) treatments: air (21 kPa O(2)+0.3 kPa CO(2)), CA(1) (5 kPa O(2)+5 kPa CO(2)) and CA(2) (10 kPa O(2)+10kPa CO(2)). Two commercially available spectrophotometers were evaluated for this purpose: a scanning monochromator (SM) of 400-2500 nm and a combination of diode array and scanning monochromator (DASM) of 350-2500 nm. Models developed using partial least squares 2-discriminant analysis (PLS2-DA) correctly classified between 81-100% of samples by post-harvest storage time, depending on the instrument used. Using similar models, the DASM instrument correctly classified 85% of samples by post-harvest treatment, compared with 72% using the SM. These results confirmed that NIR spectroscopy, coupled with the use of chemometric techniques, provides a reliable, accurate method of predicting the shelf-life of asparagus under different storage conditions and as a function of post-harvest treatment applied; the method can be readily applied at industrial level. PMID:19203619

  3. The problem of 2,4,6-trichloroanisole in cork planks studied by attenuated total reflection infrared spectroscopy: proof of concept.

    PubMed

    Garcia, Ana R; Lopes, Luís F; Brito de Barros, Ricardo; Ilharco, Laura M

    2015-01-14

    Attenuated total reflection infrared spectroscopy (ATR-IR) proved to be a promising detection technique for 2,4,6-trichloroanisole (TCA), which confers organoleptic defects to bottled alcoholic beverages, allowing the proposal of a criterion for cork plank acceptance when meant for stopper production. By analysis of a significant number of samples, it was proved that the presence of TCA, even in very low concentrations, imparts subtle changes to the cork spectra, namely, the growth of two new bands at ∼1417 (νC═C of TCA ring) and 1314 cm–1 (a shifted νCC of TCA) and an increase in the relative intensities of the bands at ∼1039 cm–1 (δCO of polysaccharides) and ∼813 cm–1 (τCH of suberin), the latter by overlapping with intense bands of TCA. These relative intensities were evaluated in comparison to a fingerprint of suberin (νasC–O–C), at 1161 cm–1. On the basis of those spectral variables, a multivariate statistics linear analysis (LDA) was performed to obtain a discriminant function that allows classifying the samples according to whether they contain or not TCA. The methodology proposed consists of a demanding acceptance criterion for cork planks destined for stopper production (with the guarantee of nonexistence of TCA) that results from combining the quantitative results with the absence of the two TCA correlated bands. ATR infrared spectroscopy is a nondestructive and easy to apply technique, both on cork planks and on stoppers, and has proven more restrictive than other techniques used in the cork industry that analyze the cleaning solutions. At the level of proof of concept, the method here proposed is appealing for high-value stopper applications.

  4. The problem of 2,4,6-trichloroanisole in cork planks studied by attenuated total reflection infrared spectroscopy: proof of concept.

    PubMed

    Garcia, Ana R; Lopes, Luís F; Brito de Barros, Ricardo; Ilharco, Laura M

    2015-01-14

    Attenuated total reflection infrared spectroscopy (ATR-IR) proved to be a promising detection technique for 2,4,6-trichloroanisole (TCA), which confers organoleptic defects to bottled alcoholic beverages, allowing the proposal of a criterion for cork plank acceptance when meant for stopper production. By analysis of a significant number of samples, it was proved that the presence of TCA, even in very low concentrations, imparts subtle changes to the cork spectra, namely, the growth of two new bands at ∼1417 (νC═C of TCA ring) and 1314 cm–1 (a shifted νCC of TCA) and an increase in the relative intensities of the bands at ∼1039 cm–1 (δCO of polysaccharides) and ∼813 cm–1 (τCH of suberin), the latter by overlapping with intense bands of TCA. These relative intensities were evaluated in comparison to a fingerprint of suberin (νasC–O–C), at 1161 cm–1. On the basis of those spectral variables, a multivariate statistics linear analysis (LDA) was performed to obtain a discriminant function that allows classifying the samples according to whether they contain or not TCA. The methodology proposed consists of a demanding acceptance criterion for cork planks destined for stopper production (with the guarantee of nonexistence of TCA) that results from combining the quantitative results with the absence of the two TCA correlated bands. ATR infrared spectroscopy is a nondestructive and easy to apply technique, both on cork planks and on stoppers, and has proven more restrictive than other techniques used in the cork industry that analyze the cleaning solutions. At the level of proof of concept, the method here proposed is appealing for high-value stopper applications. PMID:25487962

  5. A comparison of two laboratories for the measurement of wood dust using button sampler and diffuse reflection infrared Fourier-transform spectroscopy (DRIFTS).

    PubMed

    Chirila, Madalina M; Sarkisian, Khachatur; Andrew, Michael E; Kwon, Cheol-Woong; Rando, Roy J; Harper, Martin

    2015-04-01

    The current measurement method for occupational exposure to wood dust is by gravimetric analysis and is thus non-specific. In this work, diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) for the analysis of only the wood component of dust was further evaluated by analysis of the same samples between two laboratories. Field samples were collected from six wood product factories using 25-mm glass fiber filters with the Button aerosol sampler. Gravimetric mass was determined in one laboratory by weighing the filters before and after aerosol collection. Diffuse reflection mid-infrared spectra were obtained from the wood dust on the filter which is placed on a motorized stage inside the spectrometer. The metric used for the DRIFTS analysis was the intensity of the carbonyl band in cellulose and hemicellulose at ~1735 cm(-1). Calibration curves were constructed separately in both laboratories using the same sets of prepared filters from the inhalable sampling fraction of red oak, southern yellow pine, and western red cedar in the range of 0.125-4 mg of wood dust. Using the same procedure in both laboratories to build the calibration curve and analyze the field samples, 62.3% of the samples measured within 25% of the average result with a mean difference between the laboratories of 18.5%. Some observations are included as to how the calibration and analysis can be improved. In particular, determining the wood type on each sample to allow matching to the most appropriate calibration increases the apparent proportion of wood dust in the sample and this likely provides more realistic DRIFTS results.

  6. A Comparison of Two Laboratories for the Measurement of Wood Dust Using Button Sampler and Diffuse Reflection Infrared Fourier-Transform Spectroscopy (DRIFTS)

    PubMed Central

    Chirila, Madalina M.; Sarkisian, Khachatur; Andrew, Michael E.; Kwon, Cheol-Woong; Rando, Roy J.; Harper, Martin

    2015-01-01

    The current measurement method for occupational exposure to wood dust is by gravimetric analysis and is thus non-specific. In this work, diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) for the analysis of only the wood component of dust was further evaluated by analysis of the same samples between two laboratories. Field samples were collected from six wood product factories using 25-mm glass fiber filters with the Button aerosol sampler. Gravimetric mass was determined in one laboratory by weighing the filters before and after aerosol collection. Diffuse reflection mid-infrared spectra were obtained from the wood dust on the filter which is placed on a motorized stage inside the spectrometer. The metric used for the DRIFTS analysis was the intensity of the carbonyl band in cellulose and hemicellulose at ~1735 cm−1. Calibration curves were constructed separately in both laboratories using the same sets of prepared filters from the inhalable sampling fraction of red oak, southern yellow pine, and western red cedar in the range of 0.125–4 mg of wood dust. Using the same procedure in both laboratories to build the calibration curve and analyze the field samples, 62.3% of the samples measured within 25% of the average result with a mean difference between the laboratories of 18.5%. Some observations are included as to how the calibration and analysis can be improved. In particular, determining the wood type on each sample to allow matching to the most appropriate calibration increases the apparent proportion of wood dust in the sample and this likely provides more realistic DRIFTS results. PMID:25466763

  7. Development of attenuated total reflection based compression modulation step-scan Fourier transform infrared spectroscopy and its applications to rheo-spectral characterizations of polymer films.

    PubMed

    Nishikawa, Yuji; Nakano, Tatsuhiko; Miyauchi, Hiroshi; Nishikida, Koichi; Jiang, Eric Y

    2004-08-01

    Dynamic compression modulation attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic methods have been developed in this paper for characterizing polymer films. To obtain dynamic compression polarized ATR spectra, internal reflection element (IRE) secure assemblies made of tungsten carbide with very high hardness (Knoop hardness of > 1000 kgf/mm(2)) have been designed. These assemblies are mounted on the Harrick Seagull ATR attachment and measured by step-scan FT-IR spectroscopy. The effect of static compression, air gaps, and refractive index changes were examined. Experimental and simulated results showed that the effect of air gaps between the sample and IRE and refractive index changes of the sample and IRE are negligible at values larger than a static torque of 40 cN m and good signal-to-noise ratios (SNR) and reproducible data can be obtained. Uniaxially and biaxially drawn poly(ethylene terephthalate) films were measured by the presented method. Both bipolar and unipolar bands were observed in the dynamic in-phase ATR spectra, which can be associated with their micro-structural environmental changes. This technique shows promise in evaluating various polymer film materials, including biaxially oriented films, multilayer coated film surfaces, and molecular interactions between polymer-polymer and polymer-additives at the film surface.

  8. Chemical Functionalization of Germanium with Dextran Brushes for Immobilization of Proteins Revealed by Attenuated Total Reflection Fourier Transform Infrared Difference Spectroscopy.

    PubMed

    Schartner, Jonas; Hoeck, Nina; Güldenhaupt, Jörn; Mavarani, Laven; Nabers, Andreas; Gerwert, Klaus; Kötting, Carsten

    2015-07-21

    Protein immobilization studied by attenuated total reflection Fourier transform infrared (ATR-FT-IR) difference spectroscopy is an emerging field enabling the study of proteins at atomic detail. Gold or glass surfaces are frequently used for protein immobilization. Here, we present an alternative method for protein immobilization on germanium. Because of its high refractive index and broad spectral window germanium is the best material for ATR-FT-IR spectroscopy of thin layers. So far, this technique was mainly used for protein monolayers, which lead to a limited signal-to-noise ratio. Further, undesired protein-protein interactions can occur in a dense layer. Here, the germanium surface was functionalized with thiols and stepwise a dextran brush was generated. Each step was monitored by ATR-FT-IR spectroscopy. We compared a 70 kDa dextran with a 500 kDa dextran regarding the binding properties. All surfaces were characterized by atomic force microscopy, revealing thicknesses between 40 and 110 nm. To analyze the capability of our system we utilized N-Ras on mono-NTA (nitrilotriacetic acid) functionalized dextran, and the amount of immobilized Ras corresponded to several monolayers. The protein stability and loading capacity was further improved by means of tris-NTA for immobilization. Small-molecule-induced changes were revealed with an over 3 times higher signal-to-noise ratio compared to monolayers. This improvement may allow the observation of very small and so far hidden changes in proteins upon stimulus. Furthermore, we immobilized green fluorescent protein (GFP) and mCherry simultaneously enabling an analysis of the surface by fluorescence microscopy. The absence of a Förster resonance energy transfer (FRET) signal demonstrated a large protein-protein distance, indicating an even distribution of the protein within the dextran.

  9. Infrared Spectroscopy of Deuterated Compounds.

    ERIC Educational Resources Information Center

    MacCarthy, Patrick

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment (based on the potassium bromide pressed-pellet method) involving the infrared spectroscopy of deuterated compounds. Deuteration refers to deuterium-hydrogen exchange at active hydrogen sites in the molecule. (JN)

  10. A Quantitative Infrared Spectroscopy Experiment.

    ERIC Educational Resources Information Center

    Krahling, Mark D.; Eliason, Robert

    1985-01-01

    Although infrared spectroscopy is used primarily for qualitative identifications, it is possible to use it as a quantitative tool as well. The use of a standard curve to determine percent methanol in a 2,2,2-trifluoroethanol sample is described. Background information, experimental procedures, and results obtained are provided. (JN)

  11. Influence of composition and roughness on the pigment mapping of paintings using mid-infrared fiberoptics reflectance spectroscopy (mid-IR FORS) and multivariate calibration.

    PubMed

    Sessa, Clarimma; Bagán, Héctor; García, Jose Francisco

    2014-10-01

    Mid-infrared fiberoptics reflectance spectroscopy (mid-IR FORS) is a very interesting technique for artwork characterization purposes. However, the fact that the spectra obtained are a mixture of surface (specular) and volume (diffuse) reflection is a significant drawback. The physical and chemical features of the artwork surface may produce distortions in the spectra that hinder comparison with reference databases acquired in transmission mode. Several studies attempted to understand the influence of the different variables and propose procedures to improve the interpretation of the spectra. This article is focused on the application of mid-IR FORS and multivariate calibration to the analysis of easel paintings. The objectives are the evaluation of the influence of the surface roughness on the spectra, the influence of the matrix composition for the classification of unknown spectra, and the capability of obtaining pigment composition mappings. A first evaluation of a fast procedure for spectra management and pigment discrimination is discussed. The results demonstrate the capability of multivariate methods, principal component analysis (PCA), and partial least squares discrimination analysis (PLS-DA), to model the distortions of the reflectance spectra and to delimitate and discriminate areas of uniform composition. The roughness of the painting surface is found to be an important factor affecting the shape and relative intensity of the spectra. A mapping of the major pigments of a painting is possible using mid-IR FORS and PLS-DA when the calibration set is a palette that includes the potential pigments present in the artwork mixed with the appropriate binder and that shows the different paint textures.

  12. To See the World in a Grain of Sand: Recognizing the Origin of Sand Specimens by Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Multivariate Exploratory Data Analysis

    ERIC Educational Resources Information Center

    Pezzolo, Alessandra De Lorenzi

    2011-01-01

    The diffuse reflectance infrared Fourier transform (DRIFT) spectra of sand samples exhibit features reflecting their composition. Basic multivariate analysis (MVA) can be used to effectively sort subsets of homogeneous specimens collected from nearby locations, as well as pointing out similarities in composition among sands of different origins.…

  13. Visible and Mid-Infrared Supercontinuum Generation and Their Respective Application to Three-Dimensional Imaging and Stand-off Reflection Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kumar, Malay

    The thesis describes broadband supercontinuum (SC) generation in optical fibers for both the visible and mid-infrared regions of the spectrum, and their respective application to 3D imaging and stand-off reflection spectroscopy. Both SC sources leverage mature telecom technology, and are based on a common all-fiber integrated platform comprising a ˜1.55 mum distributed feedback seed laser diode amplified to high peak powers in two stages of cladding pumped Erbium or Erbium-Ytterbium fiber amplifiers. A visible SC extending from 0.45--1.20 mum with 0.74 W of time-averaged power is demonstrated using a two step process. The output of the Er-Yb power amplifier is frequency doubled to ˜0.78 mum using a periodically poled lithium niobate crystal, followed by non-linear spectral broadening in 2m of high nonlinearity photonic crystal fiber. Numerical simulations based on solving the generalized non-linear Schrodinger equation are also presented to verify the underlying SC generation mechanisms and predict further improvements. The above SC source is used in a Fourier domain line scan interferometer to measure the height and identify shape defects of ˜300 mum high solder balls in a ball grid array. The 3D imaging system has an axial resolution of ˜125 nm, transverse resolution of ˜15 mum, and an angular measurement range between 20 to 60 degrees depending on the sample surface roughness. The mid-infrared SC source is generated by pumping a 9m long ZrE 4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber to obtain a spectrum spanning 0.8--4.3 mum with 3.9 W time-averaged power. The output power is linearly scalable with pump power, but requires optimization of the critical splices and thermal management of the gain fiber and pump diodes to ensure stable high power operation. Finally, an application of the mid-IR SC is demonstrated by measuring the diffuse reflection spectra of solid samples at a stand-off distance of 5 m and 100 ms integration time. The samples can be distinguished

  14. Fatty acids and fat-soluble vitamins in ewe's milk predicted by near infrared reflectance spectroscopy. Determination of seasonality.

    PubMed

    Revilla, I; Escuredo, O; González-Martín, M I; Palacios, C

    2017-01-01

    The aim of the present work was to determine the fatty acid and fat-soluble vitamin composition and the season of ewe's milk production using NIR spectroscopy. 219 ewe's milk samples from different breeds and feeding regimes were taken each month over one year. Fatty acids were analyzed by gas chromatography, and retinol and α-, and γ-tocopherol by liquid chromatography. The results showed that the quantification was more accurate for the milk dried on paper, except for vitamins. Calibration statistical descriptors on milk dried on paper were good for capric, lauric, myristic, palmitoleic, stearic and oleic acids, and acceptable for caprilic, undecanoic, 9c, 11tCLA, ΣCLA, PUFA, ω3, ω6, retinol and α-tocopherol. The equations for the discrimination of seasonality was obtained using the partial least squares discriminant analysis (PLSDA) algorithm. 93% of winter samples and 89% of summer samples were correctly classified using the NIR spectra of milk dried on paper. PMID:27507500

  15. Characterization of REE-Bearing Minerals and Synthetic Materials Using High Resolution Ultraviolet to Near-Infrared Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hoefen, T. M.; Livo, K. E.; Giles, S. A.; Lowers, H. A.; Swayze, G. A.; Taylor, C. D.; Verplanck, P. L.; Emsbo, P.; Koenig, A.; Mccafferty, A. E.

    2014-12-01

    Diagnostic crystal field 4fn-4fn transition features in the ultraviolet (UV) to near-infrared (NIR) region of the electromagnetic spectrum have been observed in many common rare earth element (REE)-bearing minerals. The partial filling of the 4f electron shell combined with a shielding effect caused by the fully filled 5s25p6-electron shells, which weaken any effects from external magnetic or electric fields on the electrons, makes rare earth ions unique. The narrow absorption features occur as a result of parity forbidden transitions and crystal field splitting of the trivalent REEs, and since they are well shielded, only subtle wavelengths shifts are seen in their spectral features. Synthetic single REE phosphates, carbonates, oxides, hydroxides and glasses have been measured in the lab to help identify absorption band positions that are characteristic of each REE as they occur in different minerals. Because spectral resolution is critical to identifying shifts in the absorption band positions, these materials have been measured on several different high resolution spectrometers. Using a combination of Ocean Optics USB 2000+ UV-VIS, USB2000+ VIS-NIR and ASD FS 4 spectrometers we have characterized REE-bearing materials from 0.2 to 2.5 microns with a spectral resolution of ~2 nm between 0.2 and 1.0 microns and 11 to 12 nm between 1.0 and 2.5 microns. Results to date suggest that wavelength shifts and variations in the degree of crystal field splitting allow spectral differentiation between REE-bearing minerals. To support these results, a comprehensive suite of marine phosphates, paleo-beach placers, IOCG deposits, alkaline to peralkaline igneous complexes, pegmatites associated with alkaline magmas and carbonatite intrusives, have been measured and included in our database. Core, rock chips, billets, sediment samples and grab samples were manually scanned to identify the most intense or spectrally different REE features. While REE-bearing minerals have been

  16. Optimizing the models for rapid determination of chlorogenic acid, scopoletin and rutin in plant samples by near-infrared diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Mao, Zhiyi; Shan, Ruifeng; Wang, Jiajun; Cai, Wensheng; Shao, Xueguang

    2014-07-01

    Polyphenols in plant samples have been extensively studied because phenolic compounds are ubiquitous in plants and can be used as antioxidants in promoting human health. A method for rapid determination of three phenolic compounds (chlorogenic acid, scopoletin and rutin) in plant samples using near-infrared diffuse reflectance spectroscopy (NIRDRS) is studied in this work. Partial least squares (PLS) regression was used for building the calibration models, and the effects of spectral preprocessing and variable selection on the models are investigated for optimization of the models. The results show that individual spectral preprocessing and variable selection has no or slight influence on the models, but the combination of the techniques can significantly improve the models. The combination of continuous wavelet transform (CWT) for removing the variant background, multiplicative scatter correction (MSC) for correcting the scattering effect and randomization test (RT) for selecting the informative variables was found to be the best way for building the optimal models. For validation of the models, the polyphenol contents in an independent sample set were predicted. The correlation coefficients between the predicted values and the contents determined by high performance liquid chromatography (HPLC) analysis are as high as 0.964, 0.948 and 0.934 for chlorogenic acid, scopoletin and rutin, respectively.

  17. Near-infrared reflectance spectroscopy and multivariate calibration techniques applied to modelling the crude protein, fibre and fat content in rapeseed meal.

    PubMed

    Daszykowski, M; Wrobel, M S; Czarnik-Matusewicz, H; Walczak, B

    2008-11-01

    Near-infrared reflectance spectroscopy (NIRS) is often applied when a rapid quantification of major components in feed is required. This technique is preferred over the other analytical techniques due to the relatively few requirements concerning sample preparations, high efficiency and low costs of the analysis. In this study, NIRS was used to control the content of crude protein, fat and fibre in extracted rapeseed meal which was produced in the local industrial crushing plant. For modelling the NIR data, the partial least squares approach (PLS) was used. The satisfactory prediction errors were equal to 1.12, 0.13 and 0.45 (expressed in percentages referring to dry mass) for crude protein, fat and fibre content, respectively. To point out the key spectral regions which are important for modelling, uninformative variable elimination PLS, PLS with jackknife-based variable elimination, PLS with bootstrap-based variable elimination and the orthogonal partial least squares approach were compared for the data studied. They enabled an easier interpretation of the calibration models in terms of absorption bands and led to similar predictions for test samples compared to the initial models.

  18. Evaluation of low trans fat edible oils by attenuated total reflection-Fourier transform infrared spectroscopy and gas chromatography: a comparison of analytical approaches.

    PubMed

    Tyburczy, Cynthia; Mossoba, Magdi M; Fardin-Kia, Ali Reza; Rader, Jeanne I

    2012-08-01

    Current interest by the food industry in exploring reformulation options that lower the content of trans fat in edible fats and oils requires methods to accurately measure low levels of trans fat. In the present study, the quantitation of trans fat in 25 edible fat and oil samples was evaluated using two current analytical approaches, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), and gas chromatography with flame ionization detection (GC-FID) according to Official Methods of the American Oil Chemists' Society. Significant differences between the ATR-FTIR and reference GC-FID quantitations were found for samples with a trans fat content <2% of total fat. These discrepancies could be explained, in part, by the presence of certain oil constituents (e.g., vitamins, carotenoids, high levels of saturated fat) that produced absorbance bands at or near 966 cm(-1) in the ATR-FTIR spectra, a region that was previously identified as being characteristic of isolated trans double bonds. Results demonstrate that the natural content of such oil constituents could result in significant overestimations of trans fat when ATR-FTIR is used to analyze edible fats and oils with a trans fat content <2% of total fat.

  19. Use of artificial neural networks in near-infrared reflectance spectroscopy calibrations for predicting the inclusion percentages of wheat and sunflower meal in compound feedingstuffs.

    PubMed

    Pérez-Marín, D; Garrido-Varo, A; Guerrero, J E; Gutiérrez-Estrada, J C

    2006-09-01

    The use of near-infrared reflectance spectroscopy (NIRS) calibrations to predict the ingredient composition in compound feeds (i.e., inclusion percentage of each ingredient) is a complex task, regarding both the nature of the parameters to be predicted, since they are not well-defined chemical entities, and the heterogeneousness of the matrices/formulas in which each ingredient participates. The present paper evaluates the use of nonlinear regression methods, such as artificial neural networks (ANN), for developing NIRS calibrations to predict these parameters. Two of the most representative ingredients in the Spanish compound feed formulations (wheat and sunflower meal) were selected for evaluating ANN possibilities, using a large spectral library comprising a total of 7523 commercial compound feed samples; 7423 were used as training set and 100 as validation set. Three general models of networks were studied: multilayer perceptron with back-propagation training (BP), multilayer perceptron with Levenberg-Maquartd training (LM), and radial basis function nets (RBF); moreover, in accordance with a factorial design, more complex architectures were evaluated gradually, changing the number of hidden layers and hidden neurons, for the determination of the optimal network topology. For both ingredients, the best results were obtained using ANN with BP training, showing prediction error values (SEP) of 2.72% and 0.66% for wheat and sunflower meal, respectively. These SEP values showed a significant improvement (19%-49% for sunflower meal and wheat, respectively) in comparison with those obtained using calibrations developed with linear methods.

  20. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy on Intact Dried Leaves of Sage (Salvia officinalis L.): Accelerated Chemotaxonomic Discrimination and Analysis of Essential Oil Composition.

    PubMed

    Gudi, Gennadi; Krähmer, Andrea; Krüger, Hans; Schulz, Hartwig

    2015-10-01

    Sage (Salvia officinalis L.) is cultivated worldwide for its aromatic leaves, which are used as herbal spice, and for phytopharmaceutical applications. Fast analytical strategies for essential oil analysis, performed directly on plant material, would reduce the delay between sampling and analytical results. This would enhance product quality by improving technical control of cultivation. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) method described here provides a reliable calibration model for quantification of essential oil components [EOCs; R(2) = 0.96; root-mean-square error of cross-validation (RMSECV) = 0.249 mL 100 g(-1) of dry matter (DM); and range = 1.115-5.280 mL 100 g(-1) of DM] and main constituents [e.g., α-thujone/β-thujone; R(2) = 0.97/0.86; RMSECV = 0.0581/0.0856 mL 100 g(-1) of DM; and range = 0.010-1.252/0.005-0.893 mL 100 g(-1) of DM] directly on dried intact leaves of sage. Except for drying, no further sample preparation is required for ATR-FTIR, and the measurement time of less than 5 min per sample contrasts with the most common alternative of hydrodistillation followed by gas chromatography analysis, which can take several hours per sample. PMID:26360136

  1. Study of the aerosol fragrances of eugenol derivatives in Cananga odorata using diffuse reflectance infrared Fourier transform spectroscopy and gas chromatography.

    PubMed

    Kuo, Su-Ching; Chuang, Shien-Kai; Lin, Ho-Yang; Wang, Lai-Hao

    2009-10-19

    The purpose of this study was to develop and test a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method, a fast and non-destructive method without extraction, and compare it with the standard gas chromatography (GC) method currently used. A micro-orifice uniform deposit impactor (MOUDI) was used to sample all the size distributions of the aerosol particles of essential oils to investigate the relation between size distributions and the indoor concentration distributions of ylang essential oils. Correlation coefficients for DRIFTS and GC were 0.9904, 0.9910, 0.9913, and 0.9983 for eugenol, isoeugenol, methyl ether, and eugenyl acetate, respectively. The results showed that the concentrations of the four eugenol derivatives of smoke were approximately three times higher than those of mist. Additionally, the major size distributions of aerosol were 0.19 microm and 1.8 microm for the smoke and mist methods, respectively. Because these two methods produce similar results, DRIFTS is a practical method for assessing these fragrances in aerosols.

  2. Application of visible and near-infrared reflectance spectroscopy (Vis/NIRS) to determine carotenoid contents in banana (Musa spp.) fruit pulp.

    PubMed

    Davey, Mark W; Saeys, Wouter; Hof, Ellen; Ramon, Herman; Swennen, Rony L; Keulemans, Johan

    2009-03-11

    The analysis of carotenoids is complicated by the tendency of these compounds to react with radical species, leading to oxidative breakdown and isomerization during extraction. Therefore, protocols should be rapid and avoid unnecessary exposure to heat, acids, and so forth. Here, we evaluate the use of visible and near infrared reflectance spectroscopy (Vis/NIRS) to measure carotenoid contents in fruit from 28 Musa (banana and plantain) varieties. Carotenoid contents were first quantified using standardized RP-HPLC protocols, and these results were then used to develop algorithms to predict carotenoid contents from Vis/NIR spectra of the same samples. Cross-validation of the predictive algorithms across a genetically diverse group of varieties demonstrated that correlation coefficients between the HPLC measurements and the Vis/NIRS predictions varied from good for the total carotenoids and beta-carotene fractions (r(2)(cv), 0.84, 0.89) to reasonable for alpha-carotene and cis-carotenes (r(2)(cv), 0.61, 0.66), but there was only a poor correlation (r(2)(cv), 0.30) for the minor lutein component. Nonetheless, since approximately 90% of the Musa carotenoids consist of only alpha- and beta-carotene, results indicate that Vis/NIRS can be used for the high-throughput screening of fruit pulp samples for vitamin A nutritional content on the basis of their total carotenoids content. PMID:19219999

  3. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy on Intact Dried Leaves of Sage (Salvia officinalis L.): Accelerated Chemotaxonomic Discrimination and Analysis of Essential Oil Composition.

    PubMed

    Gudi, Gennadi; Krähmer, Andrea; Krüger, Hans; Schulz, Hartwig

    2015-10-01

    Sage (Salvia officinalis L.) is cultivated worldwide for its aromatic leaves, which are used as herbal spice, and for phytopharmaceutical applications. Fast analytical strategies for essential oil analysis, performed directly on plant material, would reduce the delay between sampling and analytical results. This would enhance product quality by improving technical control of cultivation. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) method described here provides a reliable calibration model for quantification of essential oil components [EOCs; R(2) = 0.96; root-mean-square error of cross-validation (RMSECV) = 0.249 mL 100 g(-1) of dry matter (DM); and range = 1.115-5.280 mL 100 g(-1) of DM] and main constituents [e.g., α-thujone/β-thujone; R(2) = 0.97/0.86; RMSECV = 0.0581/0.0856 mL 100 g(-1) of DM; and range = 0.010-1.252/0.005-0.893 mL 100 g(-1) of DM] directly on dried intact leaves of sage. Except for drying, no further sample preparation is required for ATR-FTIR, and the measurement time of less than 5 min per sample contrasts with the most common alternative of hydrodistillation followed by gas chromatography analysis, which can take several hours per sample.

  4. A new experimental setup for in situ infrared reflection absorption spectroscopy studies of atmospheric corrosion on metal surfaces considering the influence of ultraviolet light.

    PubMed

    Wiesinger, R; Kleber, Ch; Frank, J; Schreiner, M

    2009-04-01

    The knowledge available regarding the influence of ultraviolet (UV) light on the atmospheric corrosion of materials is very rudimentary. Therefore, a new experimental setup consisting of a cell for studying in situ reactions occurring at the metal/atmosphere interface by simultaneously applying infrared reflection absorption spectroscopy (IRRAS) and quartz crystal microbalance (QCM) measurements was designed and built. The cell presented consists of an acrylic glass body with a UV-light-transparent window mounted in such a way that the sample can be irradiated and weathered under controlled atmospheric conditions under a grazing angle of incidence of the IR beam. This new setup was tested by using a specimen of polycrystalline silver, where the growth of Ag(2)CO(3) and AgOH as basic silver carbonate on the surface could be observed. The weathering tests were carried out in synthetic air containing 90% relative humidity (RH) and 250 ppm CO(2), with and without UV light. The results obtained from the IRRAS spectra could be perfectly correlated with the in situ QCM data.

  5. Structure and orientation of two voltage-dependent anion-selective channel isoforms. An attenuated total reflection fourier-transform infrared spectroscopy study.

    PubMed

    Abrecht, H; Goormaghtigh, E; Ruysschaert, J M; Homble, F

    2000-12-29

    Two VDAC (voltage-dependent anion-selective channel) isoforms were purified from seed cotyledons of Phaseolus vulgaris by chromatofocusing chromatography. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was used to study the structural properties of the two isoforms reconstituted in a mixture of asolectin and 5% stigmasterol. The IR spectra of the two VDAC isoforms were highly similar indicating 50 to 53% anti-parallel beta-sheet. The orientation of the beta-strands relative to the barrel axis was calculated from the experimentally obtained dichroic ratios of the amide I beta-sheet component and the amide II band. Comparing the IR spectra of the reconstituted VDAC isoforms with the IR spectra of the bacterial porin OmpF, for which a high resolution structure is available, provided evidence for a general structural organization of the VDAC isoforms similar to that of bacterial porins. Hydrogen-deuterium exchange measurements indicated that the exchange of the amide protons occurs to a higher extent in the two VDAC isoforms than in the OmpF porin.

  6. Near-infrared reflectance spectroscopy (NIRS) for rapid determination of ginsenoside Rg1 and Re in Chinese patent medicine Naosaitong pill

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Qu, Zhengyi; Wang, Yingping; Yao, Chunlin; Bai, Xueyuan; Bian, Shuai; Zhao, Bing

    2015-03-01

    Ginsenosides in plant samples have been extensively studied because protopanaxadiol saponins are ubiquitous in Chinese patent medicines, in which they can be used in promoting human health as the main active ingredients. A method for rapid determination of two ginsenosides (Rg1 and Re) in Naosaitong (NST) samples using near-infrared reflectance spectroscopy (NIRS) is studied to determine the contents of ginsenoside Rg1 and Re in this work. Partial least square (PLS) regression was used for building the calibration models, and the effects of spectral preprocessing and variable selection on the models are investigated for optimization of the models. A total of 93 samples were scanned by NIRS, and also by high performance liquid chromatography coupled to a diode array detector to determine the contents of ginsenoside Rg1 and Re. The calibration models for Rg1 and Re had high values of the coefficient of determination (R2) (0.9766 and 0.9764) and low root mean square error of cross validation (RMSECV) (0.0136 and 0.0104), and the values of the standard error of prediction set (SEP) are 0.00764 and 0.0103, which indicate a good correlation between reference values and NIRS predicted values. The overall results show that NIRS could be applied for the rapid determination of the contents of ginsenosides in Ginseng byproducts for pharmaceuticals that develop high-quality Chinese patent medicines.

  7. Application of visible and near-infrared reflectance spectroscopy (Vis/NIRS) to determine carotenoid contents in banana (Musa spp.) fruit pulp.

    PubMed

    Davey, Mark W; Saeys, Wouter; Hof, Ellen; Ramon, Herman; Swennen, Rony L; Keulemans, Johan

    2009-03-11

    The analysis of carotenoids is complicated by the tendency of these compounds to react with radical species, leading to oxidative breakdown and isomerization during extraction. Therefore, protocols should be rapid and avoid unnecessary exposure to heat, acids, and so forth. Here, we evaluate the use of visible and near infrared reflectance spectroscopy (Vis/NIRS) to measure carotenoid contents in fruit from 28 Musa (banana and plantain) varieties. Carotenoid contents were first quantified using standardized RP-HPLC protocols, and these results were then used to develop algorithms to predict carotenoid contents from Vis/NIR spectra of the same samples. Cross-validation of the predictive algorithms across a genetically diverse group of varieties demonstrated that correlation coefficients between the HPLC measurements and the Vis/NIRS predictions varied from good for the total carotenoids and beta-carotene fractions (r(2)(cv), 0.84, 0.89) to reasonable for alpha-carotene and cis-carotenes (r(2)(cv), 0.61, 0.66), but there was only a poor correlation (r(2)(cv), 0.30) for the minor lutein component. Nonetheless, since approximately 90% of the Musa carotenoids consist of only alpha- and beta-carotene, results indicate that Vis/NIRS can be used for the high-throughput screening of fruit pulp samples for vitamin A nutritional content on the basis of their total carotenoids content.

  8. Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy.

    PubMed

    Talpur, M Younis; Kara, Huseyin; Sherazi, S T H; Ayyildiz, H Filiz; Topkafa, Mustafa; Arslan, Fatma Nur; Naz, Saba; Durmaz, Fatih; Sirajuddin

    2014-11-01

    Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer׳s law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170°C. Good regression coefficients (R(2)) were achieved for FFA, PV, IV, CD and CT with value of >0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent. PMID:25127621

  9. The characterization of caffeine and nine individual catechins in the leaves of green tea (Camellia sinensis L.) by near-infrared reflectance spectroscopy.

    PubMed

    Lee, Min-Seuk; Hwang, Young-Sun; Lee, Jinwook; Choung, Myoung-Gun

    2014-09-01

    Near-infrared reflectance spectroscopy (NIRS) was used to determine the contents of caffeine and nine individual catechins in tea leaves. A total of 665 samples were scanned by NIRS, and also by high performance liquid chromatography coupled to a diode array detector to determine the contents of caffeine and nine individual catechins. The calibration models for caffeine, EGC, C, EGCG, EC, ECG, and total catechins had high r(2) (more than 0.90) and RSP (the ratio of standard deviation of reference data to SEP(C) in the external validation set) values (more than 4.1), indicating a good correlation between reference values and NIRS predicted values. In contrast, the calibration models of GC and EGCG-3Me had low r(2) and RSP values (below 0.8 and 2.0). Therefore, these results suggest that NIRS could be applied for the rapid determination of the contents of caffeine, EGC, C, EGCG, EC, ECG, and total catechins in tea leaves for breeding programs that develop high-quality tea plants.

  10. Study of the aerosol fragrances of eugenol derivatives in Cananga odorata using diffuse reflectance infrared Fourier transform spectroscopy and gas chromatography.

    PubMed

    Kuo, Su-Ching; Chuang, Shien-Kai; Lin, Ho-Yang; Wang, Lai-Hao

    2009-10-19

    The purpose of this study was to develop and test a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method, a fast and non-destructive method without extraction, and compare it with the standard gas chromatography (GC) method currently used. A micro-orifice uniform deposit impactor (MOUDI) was used to sample all the size distributions of the aerosol particles of essential oils to investigate the relation between size distributions and the indoor concentration distributions of ylang essential oils. Correlation coefficients for DRIFTS and GC were 0.9904, 0.9910, 0.9913, and 0.9983 for eugenol, isoeugenol, methyl ether, and eugenyl acetate, respectively. The results showed that the concentrations of the four eugenol derivatives of smoke were approximately three times higher than those of mist. Additionally, the major size distributions of aerosol were 0.19 microm and 1.8 microm for the smoke and mist methods, respectively. Because these two methods produce similar results, DRIFTS is a practical method for assessing these fragrances in aerosols. PMID:19800479

  11. Detection and quantification of soymilk in cow-buffalo milk using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR).

    PubMed

    Jaiswal, Pranita; Jha, Shyam Narayan; Borah, Anjan; Gautam, Anuj; Grewal, Manpreet Kaur; Jindal, Gaurav

    2015-02-01

    Milk consumption is steadily increasing, especially in India and China, due to rising income. To bridge the gap between supply and demand, unscrupulous milk vendors add milk-like products from vegetable sources (soymilk) to milk without declaration. A rapid detection technique is required to enforce the safety norms of food regulatory authorities. Fourier Transform Infrared (FTIR) spectroscopy has demonstrated potential as a rapid quality monitoring method and was therefore explored for detection of soymilk in milk. In the present work, spectra of milk, soymilk (SM), and milk adulterated with known quantity of SM were acquired in the wave number range of 4000-500cm(-1) using Attenuated Total Reflectance (ATR)-FTIR. The acquired spectra revealed differences amongst milk, SM and adulterated milk (AM) samples in the wave number range of 1680-1058cm(-1). This region encompasses the absorption frequency of amide-I, amide-II, amide-III, beta-sheet protein, α-tocopherol and Soybean Kunitz Trypsin Inhibitor. Principal component analysis (PCA) showed clustering of samples based on SM concentration at 5% level of significance and thus SM could be detected in milk using ATR-FTIR. The SM was best predicted in the range of 1472-1241cm(-1) using multiple linear regression with coefficient of determination (R(2)) of 0.99 and 0.92 for calibration and validation, respectively.

  12. Visible and near infrared reflectance spectroscopy as a tool to monitor in situ soil organic carbon content.

    NASA Astrophysics Data System (ADS)

    Noon, C.; Stevens, A.; van Wesemael, B.

    2012-04-01

    The demand for up-to-date soil information has driven the development of rapid techniques to determine soil properties such as soil organic carbon (SOC) in situ. Proximally sensed diffuse reflectance has produced promising results. However, large scale applications are difficult to develop because the relationship between spectral data and soil properties depend on soil type and therefore is inherently local. This study aims to generate robust and locally-relevant calibration models that are applicable to a large scale database in order to provide accurate measures of SOC content in Belgian agricultural land. We collected more than 400 soil samples in South of Belgium covering 6 out 14 agro-ecological zones of the country. Soil samples were spectrally measured in laboratory with an ASD FieldSpec Pro spectroradiometer. By means of cluster analysis of the spectral library linked with several soil attributes (geographical locations, soil types, etc.) multivariate calibration models were built for each identified cluster. Based on their spectral characteristics and easy-obtainable soil attributes, these local calibration models will allow to determine the SOC content of unknown soil samples at large scales.

  13. Determination of chain orientation in the monolayers of amino-acid-derived schiff base at the air-water interface using in situ infrared reflection absorption spectroscopy.

    PubMed

    Liu, Huijin; Miao, Wangen; Du, Xuezhong

    2007-10-23

    The chain orientation in the monolayers of amino-acid-derived Schiff base, 4-(4-dodecyloxy)-2-hydroxybenzylideneamino)benzoic acid (DSA), at the air-water interface has been determined using infrared reflection absorption spectroscopy (IRRAS). On pure water, a condensed monolayer is formed with the long axes of Schiff base segments almost perpendicular to the water surface. In the presence of metal ions (Ca2+, Co2+, Zn2+, Ni2+, and Cu2+) in the subphase, the monolayer is expanded and the long axes of the Schiff base segments are inclined with respect to the monolayer normal depending on metal ion. The monolayer thickness, which is an important parameter for quantitative determination of orientation of hydrocarbon chains, is composed of alkyl chains and salicylideneaniline portions for the DSA monolayers. The effective thickness of the Schiff base portions is roughly estimated in the combination of the IRRAS results and surface pressure-area isotherms for computer simulation, since the only two observable p- and s-polarized reflectance-absorbance (RA) values can be obtained. The alkyl chains with almost all-trans conformations are oriented at an angle of about 10 degrees for H2O, 15 degrees for Ca2+, 30 degrees for Co2+, 35 degrees -40 degrees for Zn2+, and 35 degrees -40 degrees for Ni2+ with respect to the monolayer normal. The chain segments linked with gauche conformers in the case of Cu2+ are estimated to be 40 degrees -50 degrees away from the normal. PMID:17902721

  14. Discrimination of various paper types using diffuse reflectance ultraviolet-visible near-infrared (UV-Vis-NIR) spectroscopy: forensic application to questioned documents.

    PubMed

    Kumar, Raj; Kumar, Vinay; Sharma, Vishal

    2015-06-01

    Diffuse reflectance ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy is applied as a means of differentiating various types of writing, office, and photocopy papers (collected from stationery shops in India) on the basis of reflectance and absorbance spectra that otherwise seem to be almost alike in different illumination conditions. In order to minimize bias, spectra from both sides of paper were obtained. In addition, three spectra from three different locations (from one side) were recorded covering the upper, middle, and bottom portions of the paper sample, and the mean average reflectivity of both the sides was calculated. A significant difference was observed in mean average reflectivity of Side A and Side B of the paper using Student's pair >t-test. Three different approaches were used for discrimination: (1) qualitative features of the whole set of samples, (2) principal component analysis, and (3) a combination of both approaches. On the basis of the first approach, i.e., qualitative features, 96.49% discriminating power (DP) was observed, which shows highly significant results with the UV-Vis-NIR technique. In the second approach the discriminating power is further enhanced by incorporating the principal component analysis (PCA) statistical method, where this method describes each UV-Vis spectrum in a group through numerical loading values connected to the first few principal components. All components described 100% variance of the samples, but only the first three PCs are good enough to explain the variance (PC1 = 51.64%, PC2 = 47.52%, and PC3 = 0.54%) of the samples; i.e., the first three PCs described 99.70% of the data, whereas in the third approach, the four samples, C, G, K, and N, out of a total 19 samples, which were not differentiated using qualitative features (approach no. 1), were therefore subjected to PCA. The first two PCs described 99.37% of the spectral features. The discrimination was achieved by using a loading plot between

  15. Diffuse-reflectance mid-infrared spectroscopy reveals chemical differences in soil organic matter carried in different size wind eroded sediments

    NASA Astrophysics Data System (ADS)

    Padilla, Julio E.; Calderón, Francisco J.; Acosta-Martinez, Veronica; Van Pelt, Scott; Gardner, Terrence; Baddock, Matthew; Zobeck, Ted M.; Noveron, Juan C.

    2014-12-01

    Soil organic matter (SOM) is essential for soil water holding capacity, aggregation, and biodiversity. Little information is available regarding the carbon (C) functional groups carried away in wind eroded sediments away from the source soil. Mid-infrared (MidIR) spectroscopy was used on wind tunnel-blown sediments eroded from a loam soil during the fallow period of different cropping systems and tillage managements in Akron, Colorado. The soil was managed as fallow-winter wheat (Triticum aestivum L.) under conventional tillage (F-Wct) or no tillage (F-Wnt) and fallow-wheat-corn under no tillage (F-W-Cnt). Two wind eroded sediments were evaluated: fine dust (<35 μm mean dia.) and saltation-size material (<175 μm mean dia.). Our study showed that there is a partition of C groups within wind eroded sediments of different sizes and that they can reflect the tillage management history of soil. The fine dust had higher levels of aliphatic CH (2930 cm-1), and clays (3690-3620 cm-1). The saltation-sized material showed higher absorbance for quartz from 2000-1800 cm-1 and reduced absorbance from 1250-1050 cm-1. Both wind eroded sediments showed higher absorbance for -OH/NH groups and aliphatic CH from no-till soil. Finer dust sediments, which travel greater distances from the source soil than saltation size material, can carry away higher levels of aliphatic-carbon compounds and clays with potential negative impacts on SOM quantity and quality, and consequently the sustainability of these agroecosystems.

  16. Determination of thermally induced trans-fatty acids in soybean oil by attenuated total reflectance fourier transform infrared spectroscopy and gas chromatography analysis.

    PubMed

    Li, An; Ha, Yiming; Wang, Feng; Li, Weiming; Li, Qingpeng

    2012-10-24

    The intake of edible oil containing trans-fatty acids has deleterious effects mainly on the cardiovascular system. Thermal processes such as refining and frying cause the formation of trans-fatty acids in edible oil. This study was conducted to investigate the possible formation of trans-fatty acids because of the heat treatment of soybean oil. The types of trans-fatty acids in heated soybean oil are determined by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods. The effects of the heating temperature on the trans-fatty acids in soybean oil were evaluated using gas chromatography flame ionization detection analysis. Results show that heat treatment at 240 °C causes the formation of trans-fatty acids in soybean oil and the amount of trans-fatty acids increases with heating time. The only peak observed at 966 cm(-1) of the samples indicates the formation of nonconjugated trans isomers in the heated soybean oil. The major types of trans-fatty acids formed were trans-polyunsaturated fatty acids. Significant increases (P < 0.05) in the amounts of two trans-linoleic acids (C18:2-9c,12t and C18:2-9t,12c) and four trans-linolenic acids (C18:3-9c,12c,15t, C18:3-9t,12c,15c, and C18:3-9t,12t,15c/C18:3-9t,12c,15t) in soybean oil heated to temperatures exceeding 200 °C were compared with those of the control sample. The heating temperature and duration should be considered to reduce the formation of trans-fatty acids during thermal treatment.

  17. Monitoring hemodynamic and morphologic responses to closed head injury in a mouse model using orthogonal diffuse near-infrared light reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Abookasis, David; Shochat, Ariel; Mathews, Marlon S.

    2013-04-01

    The authors' aim is to assess and quantitatively measure brain hemodynamic and morphological variations during closed-head injury (CHI) in mice using orthogonal diffuse near-infrared reflectance spectroscopy (o-DRS). CHI is a type of injury to the head that does not penetrate the skull. Usually, it is caused by mechanical blows to the head and frequently occurs in traffic accidents, falls, and assaults. Measurements of brain optical properties, namely absorption and reduced scattering coefficients in the wavelength range from 650 to 1000 nm were carried out by employing different source-detector distance and locations to provide depth sensitivity on an intact scalp over the duration of the whole experiment. Furthermore, alteration in both cortical hemodynamics and morphologic markers, i.e., scattering power and amplitude properties were derived. CHI was induced in anesthetized male mice by a weight-drop model using ˜50 g cylindrical metal falling from a height of 90 cm onto the intact scalp producing an impact of 4500 g cm. With respect to baseline, difference in brain physiological properties was observed following injury up to 1 h post-trauma. Additionally, the reduced scattering spectral shapes followed Mie scattering theory was quantified and clearly shows changes in both scattering amplitude and power from baseline indicating structural variations likely from evolving cerebral edema during CHI. We further demonstrate high correlation between scattering amplitude and scattering power, with more than 20% difference in slope in comparison to preinjury. This result indicates the possibility of using the slope also as a marker for detection of structural changes. Finally, experiments investigating brain function during the first 20 min postinjury were conducted and changes in chromophore concentrations and scattering were observed. Overall, our experiments demonstrate the potential of using the proposed technique as a valuable quantitative noninvasive tool for

  18. Adsorption of formic acid on rutile TiO{sub 2} (110) revisited: An infrared reflection-absorption spectroscopy and density functional theory study

    SciTech Connect

    Mattsson, A.; Österlund, L.; Hu, Shuanglin Hermansson, K.

    2014-01-21

    Formic acid (HCOOH) adsorption on rutile TiO{sub 2} (110) has been studied by s- and p-polarized infrared reflection-absorption spectroscopy (IRRAS) and spin-polarized density functional theory together with Hubbard U contributions (DFT+U) calculations. To compare with IRRAS spectra, the results from the DFT+U calculations were used to simulate IR spectra by employing a three-layer model, where the adsorbate layer was modelled using Lorentz oscillators with calculated dielectric constants. To account for the experimental observations, four possible formate adsorption geometries were calculated, describing both the perfect (110) surface, and surfaces with defects; either O vacancies or hydroxyls. The majority species seen in IRRAS was confirmed to be the bridging bidentate formate species with associated symmetric and asymmetric frequencies of the ν(OCO) modes measured to be at 1359 cm{sup −1} and 1534 cm{sup −1}, respectively. The in-plane δ(C–H) wagging mode of this species couples to both the tangential and the normal component of the incident p-polarized light, which results in absorption and emission bands at 1374 cm{sup −1} and 1388 cm{sup −1}. IRRAS spectra measured on surfaces prepared to be either reduced, stoichiometric, or to contain surplus O adatoms, were found to be very similar. By comparisons with computed spectra, it is proposed that in our experiments, formate binds as a minority species to an in-plane Ti{sub 5c} atom and a hydroxyl, rather than to O vacancy sites, the latter to a large extent being healed even at our UHV conditions. Excellent agreement between calculated and experimental IRRAS spectra is obtained. The results emphasize the importance of protonation and reactive surface hydroxyls – even under UHV conditions – as reactive sites in e.g., catalytic applications.

  19. Quantitative determination of polyphosphate in sediments using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and partial least squares regression.

    PubMed

    Khoshmanesh, Aazam; Cook, Perran L M; Wood, Bayden R

    2012-08-21

    Phosphorus (P) is a major cause of eutrophication and subsequent loss of water quality in freshwater ecosystems. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. Despite the broad relevance of polyphosphate (Poly-P) in bioremediation and P release processes in the environment, its quantification is not yet well developed for sediment samples. Current methods possess significant disadvantages because of the difficulties associated with using a single extractant to extract a specific P compound without altering others. A fast and reliable method to estimate the quantitative contribution of microorganisms to sediment P release processes is needed, especially when an excessive P accumulation in the form of polyphosphate (Poly-P) occurs. Development of novel approaches for application of emerging spectroscopic techniques to complex environmental matrices such as sediments significantly contributes to the speciation models of P mobilization, biogeochemical nutrient cycling and development of nutrient models. In this study, for the first time Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in combination with partial least squares (PLS) was used to quantify Poly-P in sediments. To reduce the high absorption matrix components in sediments such as silica, a physical extraction method was developed to separate sediment biological materials from abiotic particles. The aim was to achieve optimal separation of the biological materials from sediment abiotic particles with minimum chemical change in the sample matrix prior to ATR-FTIR analysis. Using a calibration set of 60 samples for the PLS prediction models in the Poly-P concentration range of 0-1 mg g(-1) d.w. (dry weight of sediment) (R(2) = 0.984 and root mean square error of prediction RMSEP = 0.041 at Factor-1) Poly-P could be detected at less than 50 μg g(-l) d.w. Using this technique, there is no solvent extraction or chemical

  20. Quantitative determination of polyphosphate in sediments using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and partial least squares regression.

    PubMed

    Khoshmanesh, Aazam; Cook, Perran L M; Wood, Bayden R

    2012-08-21

    Phosphorus (P) is a major cause of eutrophication and subsequent loss of water quality in freshwater ecosystems. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. Despite the broad relevance of polyphosphate (Poly-P) in bioremediation and P release processes in the environment, its quantification is not yet well developed for sediment samples. Current methods possess significant disadvantages because of the difficulties associated with using a single extractant to extract a specific P compound without altering others. A fast and reliable method to estimate the quantitative contribution of microorganisms to sediment P release processes is needed, especially when an excessive P accumulation in the form of polyphosphate (Poly-P) occurs. Development of novel approaches for application of emerging spectroscopic techniques to complex environmental matrices such as sediments significantly contributes to the speciation models of P mobilization, biogeochemical nutrient cycling and development of nutrient models. In this study, for the first time Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in combination with partial least squares (PLS) was used to quantify Poly-P in sediments. To reduce the high absorption matrix components in sediments such as silica, a physical extraction method was developed to separate sediment biological materials from abiotic particles. The aim was to achieve optimal separation of the biological materials from sediment abiotic particles with minimum chemical change in the sample matrix prior to ATR-FTIR analysis. Using a calibration set of 60 samples for the PLS prediction models in the Poly-P concentration range of 0-1 mg g(-1) d.w. (dry weight of sediment) (R(2) = 0.984 and root mean square error of prediction RMSEP = 0.041 at Factor-1) Poly-P could be detected at less than 50 μg g(-l) d.w. Using this technique, there is no solvent extraction or chemical

  1. INSTRUMENTATION FOR FAR INFRARED SPECTROSCOPY.

    SciTech Connect

    GRIFFITHS, P.R.; HOMES, C.

    2001-05-04

    Fourier transform spectrometers developed in three distinct spectral regions in the early 1960s. Pierre Connes and his coworkers in France developed remarkably sophisticated step-scan interferometers that permitted near-infrared spectra to be measured with a resolution of better than 0.0 1 cm{sup {minus}1}. These instruments may be considered the forerunners of the step-scan interferometers made by Bruker, Bio-Rad (Cambridge, MA, USA) and Nicolet although their principal application was in the field of astronomy. Low-resolution rapid-scanning interferometers were developed by Larry Mertz and his colleagues at Block Engineering (Cambridge, MA, USA) for remote sensing. Nonetheless, the FT-IR spectrometers that are so prevalent in chemical laboratories today are direct descendants of these instruments. The interferometers that were developed for far-infrared spectrometry in Gebbie's laboratory ,have had no commercial counterparts for at least 15 years. However, it could be argued that these instruments did as much to demonstrate the power of Fourier transform spectroscopy to the chemical community as any of the instruments developed for mid- and near-infrared spectrometry. Their performance was every bit as good as today's rapid-scanning interferometers. However, the market for these instruments is so small today that it has proved more lucrative to modify rapid-scanning interferometers that were originally designed for mid-infrared spectrometry than to compete with these instruments with slow continuous scan or step-scan interferometers.

  2. Application of reflectance colorimeter measurements and infrared spectroscopy methods to rapid and nondestructive evaluation of carotenoids content in apricot (Prunus armeniaca L.).

    PubMed

    Ruiz, David; Reich, Maryse; Bureau, Sylvie; Renard, Catherine M G C; Audergon, Jean-Marc

    2008-07-01

    The importance of carotenoid content in apricot (Prunus armeniaca L.) is recognized not only because of the color that they impart but also because of their protective activity against human diseases. Current methods to assess carotenoid content are time-consuming, expensive, and destructive. In this work, the application of rapid and nondestructive methods such as colorimeter measurements and infrared spectroscopy has been evaluated for carotenoid determination in apricot. Forty apricot genotypes covering a wide range of peel and flesh colors have been analyzed. Color measurements on the skin and flesh ( L*, a*, b*, hue, chroma, and a*/ b* ratio) as well as Fourier transform near-infrared spectroscopy (FT-NIR) on intact fruits and Fourier transform mid-infrared spectroscopy (FT-MIR) on ground flesh were correlated with the carotenoid content measured by high-performance liquid chromatography. A high variability in color values and carotenoid content was observed. Partial least squares regression analyses between beta-carotene content and provitamin A activity and color measurements showed a high fit in peel, flesh, and edible apricot portion (R(2) ranged from 0.81 to 0.91) and low prediction error. Regression equations were developed for predicting carotenoid content by using color values, which appeared as a simple, rapid, reliable, and nondestructive method. However, FT-NIR and FT-MIR models showed very low R(2) values and very high prediction errors for carotenoid content.

  3. Isotope-edited infrared spectroscopy.

    PubMed

    Buchner, Ginka S; Kubelka, Jan

    2012-01-01

    Isotope-edited infrared (IR) spectroscopy is a powerful tool for studying structural and dynamical properties of peptides and proteins with site-specific resolution. Labeling of selected amide carbonyls with (13)C results in detectable sidebands of amide I' vibrations, which provide information about local conformation and/or solvent exposure without structural perturbation to the protein. Incorporation of isotopically labeled amino acids at specific positions is achieved by the chemical synthesis of the studied proteins. We describe the basic procedures for synthesis of (13)C isotopically edited protein samples, experimental IR spectroscopic measurements, and analysis of the site-specific structural changes from the thermal unfolding IR data.

  4. The potential of mid- and near-infrared diffuse reflectance spectroscopy for determining major- and trace-element concentrations in soils from a geochemical survey of North America

    USGS Publications Warehouse

    Reeves, J. B.; Smith, D.B.

    2009-01-01

    In 2004, soils were collected at 220 sites along two transects across the USA and Canada as a pilot study for a planned soil geochemical survey of North America (North American Soil Geochemical Landscapes Project). The objective of the current study was to examine the potential of diffuse reflectance (DR) Fourier Transform (FT) mid-infrared (mid-IR) and near-infrared (NIRS) spectroscopy to reduce the need for conventional analysis for the determination of major and trace elements in such continental-scale surveys. Soil samples (n = 720) were collected from two transects (east-west across the USA, and north-south from Manitoba, Canada to El Paso, Texas (USA), n = 453 and 267, respectively). The samples came from 19 USA states and the province of Manitoba in Canada. They represented 31 types of land use (e.g., national forest, rangeland, etc.), and 123 different land covers (e.g., soybeans, oak forest, etc.). The samples represented a combination of depth-based sampling (0-5 cm) and horizon-based sampling (O, A and C horizons) with 123 different depths identified. The set was very diverse with few samples similar in land use, land cover, etc. All samples were analyzed by conventional means for the near-total concentration of 49 analytes (Ctotal, Ccarbonate and Corganic, and 46 major and trace elements). Spectra were obtained using dried, ground samples using a Digilab FTS-7000 FT spectrometer in the mid- (4000-400 cm-1) and near-infrared (10,000-4000 cm-1) at 4 cm-1 resolution (64 co-added scans per spectrum) using a Pike AutoDIFF DR autosampler. Partial least squares calibrations were develop using: (1) all samples as a calibration set; (2) samples evenly divided into calibration and validation sets based on spectral diversity; and (3) samples divided to have matching analyte concentrations in calibration and validation sets. In general, results supported the conclusion that neither mid-IR nor NIRS would be particularly useful in reducing the need for conventional

  5. Use of reflectance near-infrared spectroscopy to investigate the effects of daily moisturizer application on skin optical response and barrier function.

    PubMed

    Qassem, Meha; Kyriacou, Panayiotis

    2014-08-01

    A number of noninvasive techniques and instruments have emerged over the years allowing much progress toward clarifying the structure and function of human skin and studying the effects of various applied substances. All of this research has provided great insight into the interactions between skin and various products through quantitative and qualitative measurements. Such methods include near-infrared spectroscopy (NIRS), a technique which has gained popularity over the years and has often been employed to accurately determine the moisture levels and water content of skin based on its sensitivity to hydrogen bonding. NIRS has also been applied in many studies to report the efficacy of moisturizing products and assess their benefits to the skin. However, many of these studies have reported an increase in skin water content following moisturizer application while some have challenged the benefits of long-term moisturizer use, particularly on normal skin, and even suggested that it can increase the skin's susceptibility to irritants. This paper reports the results of a pilot in vivo study carried out on the skin of 20 healthy volunteers, categorized into groups depending on their skin type and frequency of moisturizer use, in order to investigate the optical response of human skin after direct short-term contact with water followed by application of a moisturizer. The measurements were obtained using a highly advanced spectrophotometer in the region of 900 to 2100 nm equipped with a customized reflectance fiber optic handheld probe. Scatter graphs of group results and second derivative spectra have shown an interesting pattern between frequent users of moisturizers and individuals who do not use moisturizers, suggesting that long-term daily moisturization may have an effect on skin barrier function. The results also raise some questions regarding the optical characteristics of different skin types, as well as the varying response between different water bands in the

  6. Adsorption of isophorone and trimethyl-cyclohexanone on Pd(111): A combination of infrared reflection absorption spectroscopy and density functional theory studies

    NASA Astrophysics Data System (ADS)

    Dostert, Karl-Heinz; O'Brien, Casey P.; Liu, Wei; Riedel, Wiebke; Savara, Aditya; Tkatchenko, Alexandre; Schauermann, Swetlana; Freund, Hans-Joachim

    2016-08-01

    Understanding the interaction of α,β-unsaturated carbonyl compounds with late transition metals is a key prerequisite for rational design of new catalysts with desired selectivity towards C = C or C = O bond hydrogenation. The interaction of the α,β-unsaturated ketone isophorone and the saturated ketone TMCH (3,3,5-trimethylcyclohexanone) with Pd(111) was investigated in this study as a prototypical system. Infrared reflection-absorption spectroscopy (IRAS) and density functional theory calculations including van der Waals interactions (DFT + vdWsurf) were combined to form detailed assignments of IR vibrational modes in the range from 3000 cm- 1 to 1000 cm- 1 in order to obtain information on the binding of isophorone and TMCH to Pd(111) as well as to study the effect of co-adsorbed hydrogen. IRAS measurements were performed with deuterium-labeled (d5-) isophorone, in addition to unlabeled isophorone and unlabeled TMCH. Experimentally observed IR absorption features and calculated vibrational frequencies indicate that isophorone and TMCH molecules in multilayers have a mostly unperturbed structure with random orientation. At sub-monolayer coverages, strong perturbation and preferred orientations of the adsorbates were found. At low coverage, isophorone interacts strongly with Pd(111) and adsorbs in a flat-lying geometry with the C = C and C = O bonds parallel, and a CH3 group perpendicular, to the surface. At intermediate sub-monolayer coverage, the C = C bond is strongly tilted, while the C = O bond remains flat-lying, which indicates a prominent perturbation of the conjugated π system. Pre-adsorbed hydrogen leads to significant changes in the adsorption geometry of isophorone, which suggests a weakening of its binding to Pd(111). At low coverage, the structure of the CH3 groups seems to be mostly unperturbed on the hydrogen pre-covered surface. With increasing coverage, a conservation of the in-plane geometry of the conjugated π system was observed in the

  7. Surface Inspection using fourier transform infrared spectroscopy

    SciTech Connect

    Powell, G.L.; Smyrl, N.R.; Williams, D.M.; Meyers, H.M. III; Barber, T.E.; Marrero-Rivera, M.

    1994-08-08

    The use of reflectance Fourier transform infrared (FTIR) spectroscopy as a tool for surface inspection is described. Laboratory instruments and portable instruments can support remote sensing probes that can map chemical contaminants on surfaces. Detection limits under the best of conditions are in the subnanometer range (i.e., near absolute cleanliness), excellent performance is obtained in the submicrometer range, and useful performance may exist for films tens of microns thick. Identifying and quantifying contamination such as mineral oils and greases, vegetable oils, and silicone oils on aluminum foil, galvanized sheet steel, smooth aluminum tubing, and gritblasted 7075 aluminum alloy and D6AC steel are described. The ability to map in time and space the distribution of oil stains on metals is demonstrated. Techniques for quantitatively applying oils to metals, subsequently verifying the application, and nonlinear relationships between reflectance and the quantity of oil are discussed.

  8. Real-time feedback control using online attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy for continuous flow optimization and process knowledge.

    PubMed

    Skilton, Ryan A; Parrott, Andrew J; George, Michael W; Poliakoff, Martyn; Bourne, Richard A

    2013-10-01

    The use of automated continuous flow reactors is described, with real-time online Fourier transform infrared spectroscopy (FT-IR) analysis to enable rapid optimization of reaction yield using a self-optimizing feedback algorithm. This technique has been applied to the solvent-free methylation of 1-pentanol with dimethyl carbonate using a γ-alumina catalyst. Calibration of the FT-IR signal was performed using gas chromatography to enable quantification of yield over a wide variety of flow rates and temperatures. The use of FT-IR as a real-time analytical technique resulted in an order of magnitude reduction in the time and materials required compared to previous studies. This permitted a wide exploration of the parameter space to provide process understanding and validation of the optimization algorithms. PMID:24067568

  9. Infrared Spectroscopy of Explosives Residues: Measurement Techniques and Spectral Analysis

    SciTech Connect

    Phillips, Mark C.; Bernacki, Bruce E.

    2015-03-11

    Infrared laser spectroscopy of explosives is a promising technique for standoff and non-contact detection applications. However, the interpretation of spectra obtained in typical standoff measurement configurations presents numerous challenges. Understanding the variability in observed spectra from explosives residues and particles is crucial for design and implementation of detection algorithms with high detection confidence and low false alarm probability. We discuss a series of infrared spectroscopic techniques applied toward measuring and interpreting the reflectance spectra obtained from explosives particles and residues. These techniques utilize the high spectral radiance, broad tuning range, rapid wavelength tuning, high scan reproducibility, and low noise of an external cavity quantum cascade laser (ECQCL) system developed at Pacific Northwest National Laboratory. The ECQCL source permits measurements in configurations which would be either impractical or overly time-consuming with broadband, incoherent infrared sources, and enables a combination of rapid measurement speed and high detection sensitivity. The spectroscopic methods employed include standoff hyperspectral reflectance imaging, quantitative measurements of diffuse reflectance spectra, reflection-absorption infrared spectroscopy, microscopic imaging and spectroscopy, and nano-scale imaging and spectroscopy. Measurements of explosives particles and residues reveal important factors affecting observed reflectance spectra, including measurement geometry, substrate on which the explosives are deposited, and morphological effects such as particle shape, size, orientation, and crystal structure.

  10. Rapid discrimination and characterization of vanilla bean extracts by attenuated total reflection infrared spectroscopy and selected ion flow tube mass spectrometry.

    PubMed

    Sharp, Michael D; Kocaoglu-Vurma, Nurdan A; Langford, Vaughan; Rodriguez-Saona, Luis E; Harper, W James

    2012-03-01

    Vanilla beans have been shown to contain over 200 compounds, which can vary in concentration depending on the region where the beans are harvested. Several compounds including vanillin, p-hydroxybenzaldehyde, guaiacol, and anise alcohol have been found to be important for the aroma profile of vanilla. Our objective was to evaluate the performance of selected ion flow tube mass spectrometry (SIFT-MS) and Fourier-transform infrared (FTIR) spectroscopy for rapid discrimination and characterization of vanilla bean extracts. Vanilla extracts were obtained from different countries including Uganda, Indonesia, Papua New Guinea, Madagascar, and India. Multivariate data analysis (soft independent modeling of class analogy, SIMCA) was utilized to determine the clustering patterns between samples. Both methods provided differentiation between samples for all vanilla bean extracts. FTIR differentiated on the basis of functional groups, whereas the SIFT-MS method provided more specific information about the chemical basis of the differentiation. SIMCA's discriminating power showed that the most important compounds responsible for the differentiation between samples by SIFT-MS were vanillin, anise alcohol, 4-methylguaiacol, p-hydroxybenzaldehyde/trimethylpyrazine, p-cresol/anisole, guaiacol, isovaleric acid, and acetic acid. ATR-IR spectroscopy analysis showed that the classification of samples was related to major bands at 1523, 1573, 1516, 1292, 1774, 1670, 1608, and 1431 cm(-1) , associated with vanillin and vanillin derivatives.

  11. In situ nondestructive identification of natural dyes in ancient textiles by reflection fourier transform mid-infrared (FT-MIR) spectroscopy.

    PubMed

    De Luca, Eleonora; Bruni, Silvia; Sali, Diego; Guglielmi, Vittoria; Belloni, Paolo

    2015-01-01

    Silk embroideries and cotton grounds of ancient Caucasian (Kaitag) textiles were analyzed in situ by a portable Fourier transform infrared (FT-IR) spectrometer equipped with a reflection module. Differently colored areas were analyzed for the purpose of identifying the dyes fixed on the fibers. The spectra so obtained were elaborated by calculating the corresponding second derivative, and a library search was then performed using a database including the second derivative spectra of a large range of historical dyes and the corresponding undyed fibers. The results presented here suggest that this technique, combined with the library search method, has a good capability of recognizing natural dyes on both types of ancient textile fibers, in an entirely non-destructive way.

  12. In situ nondestructive identification of natural dyes in ancient textiles by reflection fourier transform mid-infrared (FT-MIR) spectroscopy.

    PubMed

    De Luca, Eleonora; Bruni, Silvia; Sali, Diego; Guglielmi, Vittoria; Belloni, Paolo

    2015-01-01

    Silk embroideries and cotton grounds of ancient Caucasian (Kaitag) textiles were analyzed in situ by a portable Fourier transform infrared (FT-IR) spectrometer equipped with a reflection module. Differently colored areas were analyzed for the purpose of identifying the dyes fixed on the fibers. The spectra so obtained were elaborated by calculating the corresponding second derivative, and a library search was then performed using a database including the second derivative spectra of a large range of historical dyes and the corresponding undyed fibers. The results presented here suggest that this technique, combined with the library search method, has a good capability of recognizing natural dyes on both types of ancient textile fibers, in an entirely non-destructive way. PMID:25587824

  13. Structural change of water with solutes and temperature up to 100 degrees C in aqueous solutions as revealed by attenuated total reflectance infrared spectroscopy.

    PubMed

    Masuda, Kaori; Haramaki, Taishiro; Nakashima, Satoru; Habert, Bertrand; Martinez, Isabelle; Kashiwabara, Seiichi

    2003-03-01

    The attenuated total reflectance infrared (ATR-IR) spectra of several aqueous solutions have been measured by using a newly developed heatable rod-type ATR cell. The OH stretching bands showed systematic change with increasing solute concentrations and these changes can be explained by four different OH components based on curve-fitting results. NaCl solutions show longer H-bond distance character, while carbonate solutions present shorter ones. The Na2CO3 1 M solution conserves this shorter H-bond nature up to 100 degrees C. On the other hand, the loose nature of NaCl solutions becomes less pronounced at higher temperatures because of the dissociation of pure water clusters. These in situ observations of water structures are generally in agreement with the expected nature of fluids within the earth. PMID:14658618

  14. Soil phosphorus and potassium estimation by reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Visible and near infrared (VNIR) diffuse reflectance spectroscopy has potential in site-specific measurement of soil properties. However, previous studies have reported VNIR estimates of plant available soil phosphorus (P) and potassium (K) to be of variable accuracy. In this study, we used a databa...

  15. Analytical study of spacecraft deposition contamination by internal reflection spectroscopy

    NASA Technical Reports Server (NTRS)

    Mookherji, T.

    1972-01-01

    Infrared absorption spectra of ten individual contaminant materials and four binary mixtures of these have been studied using the internal reflection spectroscopy technique. The effect of ultraviolet radiation on these contaminants has also been studied. It has been observed that all siloxanes, silanes, and esters are drastically affected by ultraviolet irradiation. In most cases polymerization and tar formation results.

  16. Estimating a soil quality index with VNIR reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sensor-based approaches to assessment and quantification of soil quality are important to facilitate cost-effective, site-specific soil management. The objective of this research was to evaluate the ability of visible, near-infrared (VNIR) diffuse reflectance spectroscopy to estimate multiple soil q...

  17. Characterization of silver halide fiber optics and hollow silica waveguides for use in the construction of a mid-infrared attenuated total reflection fourier transform infrared (ATR FT-IR) spectroscopy probe.

    PubMed

    Damin, Craig A; Sommer, André J

    2013-11-01

    Advances in fiber optic materials have allowed for the construction of fibers and waveguides capable of transmitting infrared radiation. An investigation of the transmission characteristics associated with two commonly used types of infrared-transmitting fibers/waveguides for prospective use in a fiber/waveguide-coupled attenuated total internal reflection (ATR) probe was performed. Characterization of silver halide polycrystalline fiber optics and hollow silica waveguides was done on the basis of the transmission of infrared light using a conventional fiber optic coupling accessory and an infrared microscope. Using the fiber optic coupling accessory, the average percent transmission for three silver halide fibers was 18.1 ± 6.1% relative to a benchtop reflection accessory. The average transmission for two hollow waveguides (HWGs) using the coupling accessory was 8.0 ± 0.3%. (Uncertainties in the relative percent transmission represent the standard deviations.) Reduced transmission observed for the HWGs was attributed to the high numerical aperture of the coupling accessory. Characterization of the fibers/waveguides using a zinc selenide lens objective on an infrared microscope indicated 24.1 ± 7.2% of the initial light input into the silver halide fibers was transmitted. Percent transmission obtained for the HWGs was 98.7 ± 0.1%. Increased transmission using the HWGs resulted from the absence or minimization of insertion and scattering losses due to the hollow air core and a better-matched numerical aperture. The effect of bending on the transmission characteristics of the fibers/waveguides was also investigated. Significant deviations in the transmission of infrared light by the solid-core silver halide fibers were observed for various bending angles. Percent transmission greater than 98% was consistently observed for the HWGs at the bending angles. The combined benefits of high percent transmission, reproducible instrument responses, and increased bending

  18. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy as a Forensic Method to Determine the Composition of Inks Used to Print the United States One-cent Blue Benjamin Franklin Postage Stamps of the 19th Century.

    PubMed

    Brittain, Harry G

    2016-01-01

    Through the combined use of infrared (IR) absorption spectroscopy and attenuated total reflectance (ATR) sampling, the composition of inks used to print the many different types of one-cent Benjamin Franklin stamps of the 19th century has been established. This information permits a historical evaluation of the formulations used at various times, and also facilitates the differentiation of the various stamps from each other. In two instances, the ink composition permits the unambiguous identification of stamps whose appearance is identical, and which (until now) have only been differentiated through estimates of the degree of hardness or softness of the stamp paper, or through the presence or absence of a watermark in the paper. In these instances, the use of ATR Fourier transform infrared spectroscopy (FT-IR) spectroscopy effectively renders irrelevant two 100-year-old practices of stamp identification. Furthermore, since the use of ATR sampling makes it possible to obtain the spectrum of a stamp still attached to its cover, it is no longer necessary to identify these blue Franklin stamps using their cancellation dates.

  19. A multivariate approach using attenuated total reflectance mid-infrared spectroscopy to measure the surface mannoproteins and β-glucans of yeast cell walls during wine fermentations.

    PubMed

    Moore, John P; Zhang, Song-Lei; Nieuwoudt, Hélène; Divol, Benoit; Trygg, Johan; Bauer, Florian F

    2015-11-18

    Yeast cells possess a cell wall comprising primarily glycoproteins, mannans, and glucan polymers. Several yeast phenotypes relevant for fermentation, wine processing, and wine quality are correlated with cell wall properties. To investigate the effect of wine fermentation on cell wall composition, a study was performed using mid-infrared (MIR) spectroscopy coupled with multivariate methods (i.e., PCA and OPLS-DA). A total of 40 yeast strains were evaluated, including Saccharomyces strains (laboratory and industrial) and non-Saccharomyces species. Cells were fermented in both synthetic MS300 and Chardonnay grape must to stationery phase, processed, and scanned in the MIR spectrum. PCA of the fingerprint spectral region showed distinct separation of Saccharomyces strains from non-Saccharomyces species; furthermore, industrial wine yeast strains separated from laboratory strains. PCA loading plots and the use of OPLS-DA to the data sets suggested that industrial strains were enriched with cell wall proteins (e.g., mannoproteins), whereas laboratory strains were composed mainly of mannan and glucan polymers.

  20. Preliminary study of an offline simultaneous determination of metoprolol tartrate and hydrochlorothiazide in powders and tablets by reflectance near-infrared spectroscopy.

    PubMed

    Vranic, Branko Z; Vandamme, Thierry F

    2015-01-01

    A preliminary study of the feasibility of using near-infrared spectroscopy (NIRS) for the offline simultaneous determination of metoprolol tartrate (MTP) and hydrochlorothiazide (HTZ) in powders and tablets has been carried out. An industrial tableting process was simulated using an instrumented tablet press replicator - Presster™. Conventional reference analytics were replaced with gravimetric analysis. The NIRS models for powder and tablet analysis were developed using 55 samples, and tested on 80 independent samples. Powder mixture components were weighed in glass vials to collect reference values, mixed and manually transferred to a tablet press replicator and compacted to form tablets. NIRS calibration models were developed using spectral and gravimetric reference data. The two model drugs were simultaneously quantified exhibiting root mean-squared error of prediction (RMSEP) of 1.69 and 1.31 mg for HTZ powder and tablet samples, respectively, and RMSEP of 3.15 and 3.00 mg for MTP powder and tablet samples, respectively. NIRS analysis of MTP and HTZ in powder and tablet form has not been reported elsewhere.

  1. Attenuated total reflectance-mid infrared spectroscopy (ATR-MIR) coupled with independent components analysis (ICA): A fast method to determine plasticizers in polylactide (PLA).

    PubMed

    Kassouf, Amine; Ruellan, Alexandre; Jouan-Rimbaud Bouveresse, Delphine; Rutledge, Douglas N; Domenek, Sandra; Maalouly, Jacqueline; Chebib, Hanna; Ducruet, Violette

    2016-01-15

    Compliance of plastic food contact materials (FCMs) with regulatory specifications in force, requires a better knowledge of their interaction phenomena with food or food simulants in contact. However these migration tests could be very complex, expensive and time-consuming. Therefore, alternative procedures were introduced based on the determination of potential migrants in the initial material, allowing the use of mathematical modeling, worst case scenarios and other alternative approaches, for simple and fast compliance testing. In this work, polylactide (PLA), plasticized with four different plasticizers, was considered as a model plastic formulation. An innovative analytical approach was developed, based on the extraction of qualitative and quantitative information from attenuated total reflectance (ATR) mid-infrared (MIR) spectral fingerprints, using independent components analysis (ICA). Two novel chemometric methods, Random_ICA and ICA_corr_y, were used to determine the optimal number of independent components (ICs). Both qualitative and quantitative information, related to the identity and the quantity of plasticizers in PLA, were retrieved through a direct and fast analytical method, without any prior sample preparations. Through a single qualitative model with 11 ICs, a clear and clean classification of PLA samples was obtained, according to the identity of plasticizers incorporated in their formulations. Moreover, a quantitative model was established for each formulation, correlating proportions estimated by ICA and known concentrations of plasticizers in PLA. High coefficients of determination (higher than 0.96) and recoveries (higher than 95%) proved the good predictability of the proposed models. PMID:26592648

  2. Attenuated total reflectance-mid infrared spectroscopy (ATR-MIR) coupled with independent components analysis (ICA): A fast method to determine plasticizers in polylactide (PLA).

    PubMed

    Kassouf, Amine; Ruellan, Alexandre; Jouan-Rimbaud Bouveresse, Delphine; Rutledge, Douglas N; Domenek, Sandra; Maalouly, Jacqueline; Chebib, Hanna; Ducruet, Violette

    2016-01-15

    Compliance of plastic food contact materials (FCMs) with regulatory specifications in force, requires a better knowledge of their interaction phenomena with food or food simulants in contact. However these migration tests could be very complex, expensive and time-consuming. Therefore, alternative procedures were introduced based on the determination of potential migrants in the initial material, allowing the use of mathematical modeling, worst case scenarios and other alternative approaches, for simple and fast compliance testing. In this work, polylactide (PLA), plasticized with four different plasticizers, was considered as a model plastic formulation. An innovative analytical approach was developed, based on the extraction of qualitative and quantitative information from attenuated total reflectance (ATR) mid-infrared (MIR) spectral fingerprints, using independent components analysis (ICA). Two novel chemometric methods, Random_ICA and ICA_corr_y, were used to determine the optimal number of independent components (ICs). Both qualitative and quantitative information, related to the identity and the quantity of plasticizers in PLA, were retrieved through a direct and fast analytical method, without any prior sample preparations. Through a single qualitative model with 11 ICs, a clear and clean classification of PLA samples was obtained, according to the identity of plasticizers incorporated in their formulations. Moreover, a quantitative model was established for each formulation, correlating proportions estimated by ICA and known concentrations of plasticizers in PLA. High coefficients of determination (higher than 0.96) and recoveries (higher than 95%) proved the good predictability of the proposed models.

  3. Attenuated total reflectance spectroscopy with chirped-pulse upconversion.

    PubMed

    Shirai, Hideto; Duchesne, Constance; Furutani, Yuji; Fuji, Takao

    2014-12-01

    Chirped-pulse upconversion technique has been applied to attenuated total reflectance (ATR) infrared spectroscopy. An extremely broadband infrared pulse was sent to an ATR diamond prism and the reflected pulse was converted to the visible by using four-wave mixing in krypton gas. Absorption spectra of liquids in the range from 200 to 5500 cm(-1) were measured with a visible spectrometer on a single-shot basis. The system was applied to observe the dynamics of exchanging process of two solvents, water and acetone, which give clear vibrational spectral contrast. We observed that the exchange was finished within ∼ 10 ms. PMID:25606893

  4. Cropland Field Monitoring: MMV Page 1 Montana Cropland Enrolled Farm Fields Carbon Sequestration Field Sampling, Measurement, Monitoring, and Verification: Application of Visible-Near Infrared Diffuse Reflectance Spectroscopy (VNIR) and Laser-induced Breakdown Spectroscopy (LIBS)

    SciTech Connect

    Lee Spangler; Ross Bricklemyer; David Brown

    2012-03-15

    There is growing need for rapid, accurate, and inexpensive methods to measure, and verify soil organic carbon (SOC) change for national greenhouse gas accounting and the development of a soil carbon trading market. Laboratory based soil characterization typically requires significant soil processing, which is time and resource intensive. This severely limits application for large-region soil characterization. Thus, development of rapid and accurate methods for characterizing soils are needed to map soil properties for precision agriculture applications, improve regional and global soil carbon (C) stock and flux estimates and efficiently map sub-surface metal contamination, among others. The greatest gains for efficient soil characterization will come from collecting soil data in situ, thus minimizing soil sample transportation, processing, and lab-based measurement costs. Visible and near-infrared diffuse reflectance spectroscopy (VisNIR) and laser-induced breakdown spectroscopy (LIBS) are two complementary, yet fundamentally different spectroscopic techniques that have the potential to meet this need. These sensors have the potential to be mounted on a soil penetrometer and deployed for rapid soil profile characterization at field and landscape scales. Details of sensor interaction, efficient data management, and appropriate statistical analysis techniques for model calibrations are first needed. In situ or on-the-go VisNIR spectroscopy has been proposed as a rapid and inexpensive tool for intensively mapping soil texture and organic carbon (SOC). While lab-based VisNIR has been established as a viable technique for estimating various soil properties, few experiments have compared the predictive accuracy of on-the-go and lab-based VisNIR. Eight north central Montana wheat fields were intensively interrogated using on-the-go and lab-based VisNIR. Lab-based spectral data consistently provided more accurate predictions than on-the-go data. However, neither in situ

  5. Remote sensing by infrared heterodyne spectroscopy

    NASA Technical Reports Server (NTRS)

    Kostiuk, T.; Mumma, M. J.

    1983-01-01

    The use of infrared heterodyne spectrocopy for the study of planetary atmospheres is discussed. Infrared heterodyne spectroscopy provides a convenient and sensitive method for measuring the true intensity profiles of atmospheric spectral lines. Application of radiative transfer theory to measured lineshapes can then permit the study of molecular abundances, temperatures, total pressures, excitation conditions, and dynamics of the regions of line formation. The theory of formation of atmospheric spectral lines and the retrieval of the information contained in these molecular lines is illustrated. Notable successes of such retrievals from infrared heterodyne measurements on Venus, Mars, Jupiter and the Earth are given. A discussion of developments in infrared heterodyne technology is also presented.

  6. Terahertz and mid-infrared reflectance of epitaxial graphene

    PubMed Central

    Santos, Cristiane N.; Joucken, Frédéric; De Sousa Meneses, Domingos; Echegut, Patrick; Campos-Delgado, Jessica; Louette, Pierre; Raskin, Jean-Pierre; Hackens, Benoit

    2016-01-01

    Graphene has emerged as a promising material for infrared (IR) photodetectors and plasmonics. In this context, wafer scale epitaxial graphene on SiC is of great interest in a variety of applications in optics and nanoelectronics. Here we present IR reflectance spectroscopy of graphene grown epitaxially on the C-face of 6H-SiC over a broad optical range, from terahertz (THz) to mid-infrared (MIR). Contrary to the transmittance, reflectance measurements are not hampered by the transmission window of the substrate, and in particular by the SiC Reststrahlen band in the MIR. This allows us to present IR reflectance data exhibiting a continuous evolution from the regime of intraband to interband charge carrier transitions. A consistent and simultaneous analysis of the contributions from both transitions to the optical response yields precise information on the carrier dynamics and the number of layers. The properties of the graphene layers derived from IR reflection spectroscopy are corroborated by other techniques (micro-Raman and X-ray photoelectron spectroscopies, transport measurements). Moreover, we also present MIR microscopy mapping, showing that spatially-resolved information can be gathered, giving indications on the sample homogeneity. Our work paves the way for a still scarcely explored field of epitaxial graphene-based THz and MIR optical devices. PMID:27102827

  7. Terahertz and mid-infrared reflectance of epitaxial graphene

    NASA Astrophysics Data System (ADS)

    Santos, Cristiane N.; Joucken, Frédéric; de Sousa Meneses, Domingos; Echegut, Patrick; Campos-Delgado, Jessica; Louette, Pierre; Raskin, Jean-Pierre; Hackens, Benoit

    2016-04-01

    Graphene has emerged as a promising material for infrared (IR) photodetectors and plasmonics. In this context, wafer scale epitaxial graphene on SiC is of great interest in a variety of applications in optics and nanoelectronics. Here we present IR reflectance spectroscopy of graphene grown epitaxially on the C-face of 6H-SiC over a broad optical range, from terahertz (THz) to mid-infrared (MIR). Contrary to the transmittance, reflectance measurements are not hampered by the transmission window of the substrate, and in particular by the SiC Reststrahlen band in the MIR. This allows us to present IR reflectance data exhibiting a continuous evolution from the regime of intraband to interband charge carrier transitions. A consistent and simultaneous analysis of the contributions from both transitions to the optical response yields precise information on the carrier dynamics and the number of layers. The properties of the graphene layers derived from IR reflection spectroscopy are corroborated by other techniques (micro-Raman and X-ray photoelectron spectroscopies, transport measurements). Moreover, we also present MIR microscopy mapping, showing that spatially-resolved information can be gathered, giving indications on the sample homogeneity. Our work paves the way for a still scarcely explored field of epitaxial graphene-based THz and MIR optical devices.

  8. Fourier transform infra-red spectroscopy using an attenuated total reflection probe to distinguish between Japanese larch, pine and citrus plants in healthy and diseased states

    NASA Astrophysics Data System (ADS)

    Gandolfo, D. S.; Mortimer, H.; Woodhall, J. W.; Boonham, N.

    2016-06-01

    FTIR spectroscopy coupled with an Attenuated Total Reflection (ATR) sampling probe has been demonstrated as a technique for detecting disease in plants. Spectral differences were detected in Japanese Larch (Larix kaempferi) infected with Phytophthora ramorum at 3403 cm-1 and 1730 cm-1, from pine (Pinus spp.) infected with Bursaphelenchus xylophilus at 1070 cm-1, 1425 cm-1, 1621 cm-1 and 3403 cm-1 and from citrus (Citrus spp.) infected with 'Candidatus liberibacter' at 960 cm-1, 1087 cm-1, 1109 cm-1, 1154 cm-1, 1225 cm-1, 1385 cm-1, 1462 cm-1, 1707 cm-1, 2882 cm-1, 2982 cm-1 and 3650 cm-1. A spectral marker in healthy citrus has been identified as Pentanone but is absent from the diseased sample spectra. This agrees with recent work by Aksenov, 2014. Additionally, the spectral signature of Cutin was identified in the spectra of Pinus spp. and Citrus spp. and is consistent with work by Dubis, 1999 and Heredia-Guerrero, 2014.

  9. Nondestructive and rapid determination of nitrate in soil, dry deposits and aerosol samples using KBr-matrix with diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS).

    PubMed

    Verma, Santosh Kumar; Deb, Manas Kanti

    2007-01-23

    This paper presents the development of a new, rapid and precise analytical method for submicrogram levels of nitrate (NO3-) in environmental samples like soil, dry deposit samples, and coarse and fine aerosol particles. The determination of submicrogram levels of nitrate is based on the selection of a quantitative analytical peak at 1385 cm(-1) among the three observed vibrational peaks and preparing calibration curves using different known concentrations of nitrate by diffuse reflectance Fourier transform infra red spectrometric (DRIFTS) technique. Pre-weighed and ground infrared (IR) grade KBr was used as substrate over which remarkably wide range of known concentration of nitrate was sprayed and dried. The dried sample was analyzed by DRIFTS and absorbance was measured. Eight calibration curves for four different concentration ranges of nitrate for absorbance as well as peak area were prepared for samples containing lower and relatively higher values of nitrate. The relative standard deviation (n=8) for the nitrate concentration ranges, 0.05-40, 0.05-1.5, 1.5-25, 5-40 microg/0.1 g KBr were in the range 1.6-2.3% for the above calibration curves. The limit of detection (LOD) of the method is 0.07 microg g(-1) NO3-. The F- and t-tests were performed to check the analytical quality assurance test. The noteworthy feature of the reported method is the noninterference of any of the associated cations. The results were compared with that of ion-chromatographic method with high degree of acceptability. The method can be applied in wide concentration ranges. The method is reagent less, nondestructive, very fast, repeatable, and accurate and has high sample throughput value.

  10. Combined theory of reflectance and emittance spectroscopy

    NASA Technical Reports Server (NTRS)

    Hapke, Bruce

    1995-01-01

    The theory in which either or both reflected sunlight and thermally emitted radiation contribute to the power received by a detector viewing a particulate medium, such as a powder in the laboratory or a planetary regolith, is considered theoretically. This theory is of considerable interest for the interpretation of data from field or spacecraft instruments that are sensitive to the near-infrared region of the spectrum, such as NIMS (near-infrared mapping spectrometer) and VIMS (visual and infrared mapping spectrometer), as well as thermal infrared detectors.

  11. [Infrared spectroscopy based on quantum cascade lasers].

    PubMed

    Wen, Zhong-Quan; Chen, Gang; Peng, Chen; Yuan, Wei-Qing

    2013-04-01

    Quantum cascade lasers (QCLs) are promising infrared coherent sources. Thanks to the quantum theory and band-gap engineering, QCL can access the wavelength in the range from 3 to 100 microm. Since the fingerprint spectrum of most gases are located in the mid-infrared range, mid-infrared quantum cascade laser based gas sensing technique has become the research focus world wide because of its high power, narrow linewidth and fast scanning. Recent progress in the QCL technology leads to a great improvement in laser output power and efficiency, which stimulates a fast development in the infrared laser spectroscopy. The present paper gives a broad review on the QCL based spectroscopy techniques according to their working principles. A discussion on their applications in gas sensing and explosive detecting is also given at the end of the paper.

  12. GEMAS: prediction of solid-solution phase partitioning coefficients (Kd) for oxoanions and boric acid in soils using mid-infrared diffuse reflectance spectroscopy.

    PubMed

    Janik, Leslie J; Forrester, Sean T; Soriano-Disla, José M; Kirby, Jason K; McLaughlin, Michael J; Reimann, Clemens

    2015-02-01

    The authors' aim was to develop rapid and inexpensive regression models for the prediction of partitioning coefficients (Kd), defined as the ratio of the total or surface-bound metal/metalloid concentration of the solid phase to the total concentration in the solution phase. Values of Kd were measured for boric acid (B[OH]3(0)) and selected added soluble oxoanions: molybdate (MoO4(2-)), antimonate (Sb[OH](6-)), selenate (SeO4(2-)), tellurate (TeO4(2-)) and vanadate (VO4(3-)). Models were developed using approximately 500 spectrally representative soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS) program. These calibration soils represented the major properties of the entire 4813 soils of the GEMAS project. Multiple linear regression (MLR) from soil properties, partial least-squares regression (PLSR) using mid-infrared diffuse reflectance Fourier-transformed (DRIFT) spectra, and models using DRIFT spectra plus analytical pH values (DRIFT + pH), were compared with predicted log K(d + 1) values. Apart from selenate (R(2)  = 0.43), the DRIFT + pH calibrations resulted in marginally better models to predict log K(d + 1) values (R(2)  = 0.62-0.79), compared with those from PSLR-DRIFT (R(2)  = 0.61-0.72) and MLR (R(2)  = 0.54-0.79). The DRIFT + pH calibrations were applied to the prediction of log K(d + 1) values in the remaining 4313 soils. An example map of predicted log K(d + 1) values for added soluble MoO4(2-) in soils across Europe is presented. The DRIFT + pH PLSR models provided a rapid and inexpensive tool to assess the risk of mobility and potential availability of boric acid and selected oxoanions in European soils. For these models to be used in the prediction of log K(d + 1) values in soils globally, additional research will be needed to determine if soil variability is accounted on the calibration.

  13. Detecting and Segregating Black Tip-Damaged Wheat Kernels Using Visible and Near Infrared Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Detection of individual wheat kernels with black tip symptom (BTS) and black tip damage (BTD) was demonstrated using near infrared reflectance spectroscopy (NIRS) and silicon light-emitting-diode (LED) based instruments. The two instruments tested, a single kernel near-infrared spectroscopy instrume...

  14. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, P.H.

    1998-09-22

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer ({micro}m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 {micro}m or, for cool smoky fires, about 2 {micro}m to about 16 {micro}m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 {micro}m to about 2 {micro}m and thin leafing aluminum flake pigments. 4 figs.

  15. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, Paul H.

    1998-01-01

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer (.mu.m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 .mu.m or, for cool smoky fires, about 2 .mu.m to about 16 .mu.m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 .mu.m to about 2 .mu.m and thin leafing aluminum flake pigments.

  16. Fiberoptic evanescent wave infrared spectroscopy of gases in liquids

    NASA Astrophysics Data System (ADS)

    Bunimovich, D.; Belotserkovsky, E.; Katzir, A.

    1995-04-01

    Silver halide optical fibers were used as attenuated total reflection elements for infrared evanescent wave spectroscopy of gases in liquids. The evanescent wave absorption spectra of chlorodifluoromethane (Freon-22) and carbon dioxide gases (CO2) in water were studied and the dependence on vapor pressure of the gas and temperature was investigated. Absorption peaks were easily traced and correlated well with those in the literature. The use of the infrared (IR) fibers in the fiberoptic evanescent wave spectroscopy system bypasses the difficulty of ordinary IR spectroscopy related to the strong IR absorption of most liquid solvents, and provides a flexible, easy, and inexpensive way of determining the presence and concentration of gases in liquids to within about 5% accuracy.

  17. Analysis of various quality attributes of sunflower and soybean plants by near infra-red reflectance spectroscopy: Development and validation calibration models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sunflower and soybean are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems. Rapid and low cost methods of analyzing plant quality would be helpful for crop management. We developed and validated calibration models for Near-infrar...

  18. Flap monitoring using infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Keller, Alex; Wright, Leigh P.; Elmandjra, Mohamed; Mao, Jian-min

    2006-02-01

    We report results of clinical trials on flap monitoring in 65 plastic surgeries. Hemoglobin oxygen saturation of flap tissue (StO II) was monitored non-invasively by using ODISsey TM tissue oximeter, an infrared spectroscopic device. StO II measurements were conducted both intra-operatively and post-operatively. From the intra-operative measurements, we observed that StO II values dropped when the main blood vessels supplying the flap were clamped in surgery, and that StO II jumped after anastomosis to a value close to its pre-operative value. From post-operative monitoring measurements for the 65 flap cases, each lasted two days or so, we found that the StO II values approach to a level close to the baseline if the surgery was successful, and that the StO II value dropped to a value below 30% if there is a perfusion compromise, such as vascular thrombosis.

  19. Infrared spectroscopy of ionic clusters

    SciTech Connect

    Price, J.M. . Dept. of Chemistry Lawrence Berkeley Lab., CA )

    1990-11-01

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm{sup {minus}1} region. The species studied include: the hydrated hydronium ions, H{sub 3}O{sup +} (H{sub 2}O){sub 3 {minus}10}, ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub 1 {minus}10} and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH{sub 4}{sup +}(NH{sub 3}){sub n}(H{sub 2}O){sub m} (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs.

  20. Blood glucose measurement by infrared spectroscopy.

    PubMed

    Zeller, H; Novak, P; Landgraf, R

    1989-02-01

    For the development of an implantable artificial endocrine pancreas, a sensor for blood glucose measurement is needed providing a long-term stability. This goal can be achieved by the application of infrared spectroscopy which, unlike electrochemical sensors, responds directly to the glucose molecule. An investigation under physiological conditions revealed five glucose absorption bands in the near and middle infrared range. These are 1040, 1085, 1109, 1160 and 1365 cm-1. Only the 1040 cm-1 frequency coincides with none of the other infrared-active blood substances like proteins, lipids and urea. Nevertheless, the other absorption bands too, especially the 1109 cm-1 frequency, can be used for blood glucose measurement, if the superimposed absorptions are compensated. Methods for the compensation have been found. Technically feasible embodiments of an infrared glucose sensor are described.

  1. Noninvasive determination of absorption and reduced scattering coefficients of adult heads by time-resolved reflectance measurements for functional near infra-red spectroscopy.

    PubMed

    Tanifuji, T; Wang, L

    2014-01-01

    Absorption and reduced scattering coefficients (μ(a) and μ'(s)) of adult heads have been noninvasively determined by time-resolved reflectance measurements. The finite difference time domain (FDTD) analysis was used to calculate time-resolved reflectance from realistic adult head models with brain grooves containing a non-scattering layer. In vivo time-resolved reflectances of human heads were measured by a system composed of a time-correlated single photon counter and a diode laser. By minimizing the objective functions that compare theoretical and experimental time resolved reflectances, μ(a) and μ'(s) of brain were determined. It became clear that time-resolved measurements have enough sensitivity to determine both μ(a) and μ'(s) for superficial tissues, gray matter and white matter, except μ(s) for white matter.

  2. Comparing near-infrared conventional diffuse reflectance spectroscopy and hyperspectral imaging for determination of the bulk properties of solid samples by multivariate regression: determination of Mooney viscosity and plasticity indices of natural rubber.

    PubMed

    Juliano da Silva, Carlos; Pasquini, Celio

    2015-01-21

    Conventional reflectance spectroscopy (NIRS) and hyperspectral imaging (HI) in the near-infrared region (1000-2500 nm) are evaluated and compared, using, as the case study, the determination of relevant properties related to the quality of natural rubber. Mooney viscosity (MV) and plasticity indices (PI) (PI0 - original plasticity, PI30 - plasticity after accelerated aging, and PRI - the plasticity retention index after accelerated aging) of rubber were determined using multivariate regression models. Two hundred and eighty six samples of rubber were measured using conventional and hyperspectral near-infrared imaging reflectance instruments in the range of 1000-2500 nm. The sample set was split into regression (n = 191) and external validation (n = 95) sub-sets. Three instruments were employed for data acquisition: a line scanning hyperspectral camera and two conventional FT-NIR spectrometers. Sample heterogeneity was evaluated using hyperspectral images obtained with a resolution of 150 × 150 μm and principal component analysis. The probed sample area (5 cm(2); 24,000 pixels) to achieve representativeness was found to be equivalent to the average of 6 spectra for a 1 cm diameter probing circular window of one FT-NIR instrument. The other spectrophotometer can probe the whole sample in only one measurement. The results show that the rubber properties can be determined with very similar accuracy and precision by Partial Least Square (PLS) regression models regardless of whether HI-NIR or conventional FT-NIR produce the spectral datasets. The best Root Mean Square Errors of Prediction (RMSEPs) of external validation for MV, PI0, PI30, and PRI were 4.3, 1.8, 3.4, and 5.3%, respectively. Though the quantitative results provided by the three instruments can be considered equivalent, the hyperspectral imaging instrument presents a number of advantages, being about 6 times faster than conventional bulk spectrometers, producing robust spectral data by ensuring sample

  3. Application of Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) Spectroscopy To Determine the Chlorogenic Acid Isomer Profile and Antioxidant Capacity of Coffee Beans.

    PubMed

    Liang, Ningjian; Lu, Xiaonan; Hu, Yaxi; Kitts, David D

    2016-01-27

    The chlorogenic acid isomer profile and antioxidant activity of both green and roasted coffee beans are reported herein using ATR-FTIR spectroscopy combined with chemometric analyses. High-performance liquid chromatography (HPLC) quantified different chlorogenic acid isomer contents for reference, whereas ORAC, ABTS, and DPPH were used to determine the antioxidant activity of the same coffee bean extracts. FTIR spectral data and reference data of 42 coffee bean samples were processed to build optimized PLSR models, and 18 samples were used for external validation of constructed PLSR models. In total, six PLSR models were constructed for six chlorogenic acid isomers to predict content, with three PLSR models constructed to forecast the free radical scavenging activities, obtained using different chemical assays. In conclusion, FTIR spectroscopy, coupled with PLSR, serves as a reliable, nondestructive, and rapid analytical method to quantify chlorogenic acids and to assess different free radical-scavenging capacities in coffee beans. PMID:26725502

  4. Application of Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) Spectroscopy To Determine the Chlorogenic Acid Isomer Profile and Antioxidant Capacity of Coffee Beans.

    PubMed

    Liang, Ningjian; Lu, Xiaonan; Hu, Yaxi; Kitts, David D

    2016-01-27

    The chlorogenic acid isomer profile and antioxidant activity of both green and roasted coffee beans are reported herein using ATR-FTIR spectroscopy combined with chemometric analyses. High-performance liquid chromatography (HPLC) quantified different chlorogenic acid isomer contents for reference, whereas ORAC, ABTS, and DPPH were used to determine the antioxidant activity of the same coffee bean extracts. FTIR spectral data and reference data of 42 coffee bean samples were processed to build optimized PLSR models, and 18 samples were used for external validation of constructed PLSR models. In total, six PLSR models were constructed for six chlorogenic acid isomers to predict content, with three PLSR models constructed to forecast the free radical scavenging activities, obtained using different chemical assays. In conclusion, FTIR spectroscopy, coupled with PLSR, serves as a reliable, nondestructive, and rapid analytical method to quantify chlorogenic acids and to assess different free radical-scavenging capacities in coffee beans.

  5. Explosive detection using infrared laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Hildenbrand, J.; Herbst, J.; Wöllenstein, J.; Lambrecht, A.

    2009-01-01

    Stand-off and extractive explosive detection methods for short distances are investigated using mid-infrared laser spectroscopy. A quantum cascade laser (QCL) system for TATP-detection by open path absorption spectroscopy in the gas phase was developed. In laboratory measurements a detection limit of 5 ppm*m was achieved. For explosives with lower vapor pressure an extractive hollow fiber based measurement system was investigated. By thermal desorption gaseous TATP or TNT is introduced into a heated fiber. The small sample volume and a fast gas exchange rate enable fast detection. TNT and TATP detection levels below 100 ng are feasible even in samples with a realistic contaminant background.

  6. Narrowband Mid-infrared reflectance filters using guided mode resonance

    PubMed Central

    Kodali, Anil K.; Schulmerich, Matthew; Ip, Jason; Yen, Gary; Cunningham, Brian T.; Bhargava, Rohit

    2010-01-01

    There is a need to develop mid-infrared (IR) spectrometers for applications in which the absorbance of only a few vibrational mode (optical) frequencies needs to be recorded; unfortunately, there are limited alternatives for the same. The key requirement is the development of a means to access discretely a small set of spectral positions from the wideband thermal sources commonly used for spectroscopy. We present here the theory, design and practical realization of a new class of filters in the mid-infrared (IR) spectral regions based on using guided mode resonances (GMR) for narrowband optical reflection. A simple, periodic surface-relief configuration is chosen to enable both a spectral response and facile fabrication. A theoretical model based on rigorous coupled wave analysis is developed, incorporating anomalous dispersion of filter materials in the mid-IR spectral region. As a proof-of-principle demonstration, a set of four filters for a spectral region around the C-H stretching mode (2600–3000 cm−1) are fabricated and responses compared to theory. The reflectance spectra were well-predicted by the developed theory and results were found to be sensitive to the angle of incidence and dispersion characteristics of the material. In summary, the work reported here forms the basis for a rational design of filters that can prove useful for IR absorption spectroscopy. PMID:20527738

  7. Comments on a peak of AlxGa1-xN observed by infrared reflectance

    NASA Astrophysics Data System (ADS)

    Marx, G.; Engelbrecht, J. A. A.; Lee, M. E.; Wagener, M. C.; Henry, A.

    2016-05-01

    AlxGa1-xN epilayers, grown on c-plane oriented sapphire substrates by metal organic chemical vapour deposition (MOCVD), were evaluated using FTIR infrared reflectance spectroscopy. A peak at ∼850 cm-1 in the reflectance spectra, not reported before, was observed. Possible origins for this peak are considered and discussed.

  8. Emerging techniques for soil analysis via mid-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Linker, R.; Shaviv, A.

    2009-04-01

    Transmittance and diffuse reflectance (DRIFT) spectroscopy in the mid-IR range are well-established methods for soil analysis. Over the last five years, additional mid-IR techniques have been investigated, and in particular: 1. Attenuated total reflectance (ATR) Attenuated total reflectance is commonly used for analysis of liquids and powders for which simple transmittance measurements are not possible. The method relies on a crystal with a high refractive index, which is in contact with the sample and serves as a waveguide for the IR radiation. The radiation beam is directed in such a way that it hits the crystal/sample interface several times, each time penetrating a few microns into the sample. Since the penetration depth is limited to a few microns, very good contact between the sample and the crystal must be ensured, which can be achieved by working with samples close to water saturation. However, the strong absorbance of water in the mid-infrared range as well as the absorbance of some soil constituents (e.g., calcium carbonate) interfere with some of the absorbance bands of interest. This has led to the development of several post-processing methods for analysis of the spectra. The FTIR-ATR technique has been successfully applied to soil classification as well as to determination of nitrate concentration [1, 6-8, 10]. Furthermore, Shaviv et al. [12] demonstrated the possibility of using fiber optics as an ATR devise for direct determination of nitrate concentration in soil extracts. Recently, Du et al. [5] showed that it is possible to differentiate between 14N and 15N in such spectra, which opens very promising opportunities for developing FTIR-ATR based methods for investigating nitrogen transformation in soils by tracing changes in N-isotopic species. 2. Photo-acoustic spectroscopy Photoacoustic spectroscopy (PAS) is based on absorption-induced heating of the sample, which produces pressure fluctuations in a surrounding gas. These fluctuations are

  9. Label-Free Determination of Protein Binding in Aqueous Solution using Overlayer Enhanced Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (OE-ATR-FTIR)

    NASA Astrophysics Data System (ADS)

    Ruthenburg, Travis; Aweda, Tolulope; Park, Simon; Meares, Claude; Land, Donald

    2009-03-01

    Protein binding/affinity studies are often performed using Surface Plasmon Resonance techniques that don't produce much spectral information. Measurement of protein binding affinity using FTIR is traditionally performed using high protein concentration or deuterated solvent. By immobilizing a protein near the surface of a gold-coated germanium internal reflection element interactions can be measured between an immobilized protein and free proteins or small molecules in aqueous solution. By monitoring the on and off rates of these interactions, the dissociation constant for the system can be determined. The dissociation constant for the molecule Yttrium-DOTA binding to the antibody 2D12.5 system was determined to be 100nM. Results will also be presented from our measurements of Bovine Serum Albumin (BSA) binding to anti-BSA.

  10. Rapid analysis of effluents generated by the dairy industry for fat determination by preconcentration in nylon membranes and attenuated total reflectance infrared spectroscopy measurement.

    PubMed

    Moliner Martínez, Y; Muñoz-Ortuño, M; Herráez-Hernández, R; Campíns-Falcó, P

    2014-02-01

    This paper describes a new approach for the determination of fat in the effluents generated by the dairy industry which is based on the retention of fat in nylon membranes and measurement of the absorbances on the membrane surface by ATR-IR spectroscopy. Different options have been evaluated for retaining fat in the membranes using milk samples of different origin and fat content. Based on the results obtained, a method is proposed for the determination of fat in effluents which involves the filtration of 1 mL of the samples through 0.45 µm nylon membranes of 13 mm diameter. The fat content is then determined by measuring the absorbance of band at 1745 cm(-1). The proposed method can be used for the direct estimation of fat at concentrations in the 2-12 mg/L interval with adequate reproducibility. The intraday precision, expressed as coefficients of variation CVs, were ≤ 11%, whereas the interday CVs were ≤ 20%. The method shows a good tolerance towards conditions typically found in the effluents generated by the dairy industry. The most relevant features of the proposed method are simplicity and speed as the samples can be characterized in a few minutes. Sample preparation does not involve either additional instrumentation (such as pumps or vacuum equipment) or organic solvents or other chemicals. Therefore, the proposed method can be considered a rapid, simple and cost-effective alternative to gravimetric methods for controlling fat content in these effluents during production or cleaning processes.

  11. A new near-infrared reflectance spectroscopy method for high-throughput analysis of oleic acid and linolenic acid content of single seeds in oilseed rape (Brassica napus L.).

    PubMed

    Niewitetzki, Oliver; Tillmann, Peter; Becker, Heiko C; Möllers, Christian

    2010-01-13

    The development of oilseed rape cultivars with a high content of oleic acid (18:1) and a low content of linolenic acid (18:3) in the seed oil is an important breeding aim. Oil of this quality is increasingly being sought by the food and the oleochemical industry. Since the oil quality is determined by the genotype of the seed, a selection can be performed among single seeds of segregating populations. For this purpose a high-throughput Near-Infrared Reflectance Spectroscopy (NIRS) method using an automated sample presentation unit for single seeds of oilseed rape and a spectrometer equipped with a photodiode array detector was developed. Single-seed analyses have been accomplished with a throughput of up to 800 seeds per hour. Seeds from segregating populations of different origin were analyzed by NIRS and gas chromatography. Calibration equations were developed and validated applying the Modified Partial Least Square regression (MPLS) and LOCAL procedure. In three independent validations, standard errors of prediction corrected for bias between 2.7% and 3.7% for oleic acid and 1.2% and 1.8% for linolenic acid were determined using MPLS. Similar results were obtained applying the LOCAL procedure. The results show that the new high-throughput method can be applied to predict the oleic acid and linolenic acid content of single seeds of oilseed rape.

  12. A study of surface film formation on LiNi0.8Co0.15Al0.05O2 cathodes u sing attenuated total reflection infrared spectroscopy

    SciTech Connect

    Song, S.-W.; Zhuang, G.V.; Ross Jr., P.N.

    2004-01-19

    The surface films formed on commercial LiNi0.8Co0.15Al0.05O2 cathodes (ATD Gen2) charged from 3.75V to 4.2V vs. Li/Li+ in EC:DEC - 1M LiPF6 were analyzed using ex-situ Fourier transform infrared spectroscopy (FTIR) with the attenuated total reflection (ATR) technique. A surface layer of Li2CO3 is present on the virgin cathode, probably from reaction of the active material with air during the cathode preparation procedure. The Li2CO3 layer disappeared even after soaking in the electrolyte, indicating that the layer dissolved into the electrolyte possibly even before potential cycling of the electrode. IR features only from the binder (PVdF) and a trace of polyamide from the Al current collector were observed on the surfaces of cathodes charged to below 4.2 V, i.e., no surface species from electrolyte oxidation. Some new IR features were, however, found on the cathode charged to 4.2 V and higher. An electrolyte oxidation product was observed that appeared to contain dicarbonyl anhydride and (poly)ester functionalities. The reaction appears to be an indirect electrochemical oxidation with overcharging (removal of > 0.6 Li ions) destabilizing oxygen in the oxide lattice resulting in oxygen transfer to the solvent molecules.

  13. Comparison of molecular orientation and phase transition behaviors in the two kinds of ordered ultrathin films of reversed duckweed polymer ES-3 studied by infrared grazing reflection-absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Xu, Weiqing; Zhao, Bing

    2003-03-01

    A multilayer LB film and a casting film of reversed duckweed polymer ES-3 on Au-evaporated glass slides were investigated by Fourier Transform infrared grazing reflection-absorption spectroscopy. It is found that the two kinds of ordered ultrathin films have different orientation of alkyl chains, nearly perpendicular to the substrate surface for the LB film while rather tilted for the casting film. The studies on their thermal transition behaviors indicate that both of the films have three phase transition processes, respectively, occurring near 65, 105 and 140 °C for the former while near 80, 105 and 140 °C for the latter, but show different transition behavior in the each corresponding transition process. It is referred that at room temperature there are island-like domain structures formed in the LB film, but no ones in the casting film; however, the latter can form the domain structures between the first two transition points due to the desorption of solvents. The formation of domain structure seems to play two important roles, one of which is to make alkyl chains more perpendicular to the substrate surface, and the other to make alkyl chains more packed closely. Thermal cyclic experiments reveal that neither of the films could return to its original state after thermal cyclic treatment up to the temperature, which is above the third transition point, although its alkyl chain becomes highly ordered again.

  14. A spectroelectrochemical cell for ultrafast two-dimensional infrared spectroscopy

    SciTech Connect

    El Khoury, Youssef; Van Wilderen, Luuk J. G. W.; Vogt, Tim; Winter, Ernst; Bredenbeck, Jens E-mail: bredenbeck@biophysik.uni-frankfurt.de

    2015-08-15

    A spectroelectrochemical cell has been designed to combine electrochemistry and ultrafast two-dimensional infrared (2D-IR) spectroscopy, which is a powerful tool to extract structure and dynamics information on the femtosecond to picosecond time scale. Our design is based on a gold mirror with the dual role of performing electrochemistry and reflecting IR light. To provide the high optical surface quality required for laser spectroscopy, the gold surface is made by electron beam evaporation on a glass substrate. Electrochemical cycling facilitates in situ collection of ultrafast dynamics of redox-active molecules by means of 2D-IR. The IR beams are operated in reflection mode so that they travel twice through the sample, i.e., the signal size is doubled. This methodology is optimal for small sample volumes and successfully tested with the ferricyanide/ferrocyanide redox system of which the corresponding electrochemically induced 2D-IR difference spectrum is reported.

  15. [Rapid determination of the multi-marker ingredients in Heterosmilacis Japonicae Rhizoma and Sophorae Flavescentis Radix with near-infrared diffused reflection spectroscopy].

    PubMed

    Zhao, Feng-Chun; Wan, Kai-Yang; Liu, Xiao-Qian; Zhang, Qi-Wei; Gao, Hui-Min; Wang, Zhi-Min

    2014-10-01

    A rapid NIRS method for determination of macrozamin in Heterosmilacis japonicae rhizoma (HJR), and the total content of oxymatrine and matrine (OMT + MT) as well as the total content of oxysophocarpine and sophocarpine (OSC + SC) in sophorae flavescens radix (SFR) was developed to explore the application feasibility of NIRS for the quality assurance system of Chinese patent drugs. The contents of macrozamin in HJR samples, and OMT + MT and OSC + SC in SFR samples were determined by HPLC as reference values. The NIR spectra of the samples were measured in a diffused reflection mode. The different characteristic wavebands and pretreatment methods were optimized. The quantitative calibration models between the NIR spectra and the content reference values of marker components in HJR and SFR samples, were established with partial least square method, and further optimized through the cross validation and external validation. The contents of macrozamin in 88 batches of HJR samples were over the range of 0.36-12.88 mg · g(-1). The total contents of OMT + MT and OSC + SC in 75 batches of SFR samples were over the range of 8.87-66.31 and 2.30-15.11 mg · g(-1), respectively. The performance of the final models for macrozamin, OMT + MT and OSC + SC was evaluated well according to correlation coefficients (r), root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP). The R2 values of the cross-validation for macrozamin, OMT + MT and OSC + SC were 0.9025, 0.9491 and 0.9137, and those of RMSECV were 0.961, 2.45 and 0.724 mg · g(-1) respectively. The R2 values of external validation for the three models were 0.9817, 0.9826 and 0.9609, and those of RMSEP were 0.693, 2.27 and 0.658 mg · g(-1), respectively. This is the first report on rapid determination of macrozamin in Heterosmilacis japonicae rhizoma, and oxymatrine, matrine, oxysophocarpine and sophocarpine in sophorae flavescens radix by NIRS method. The presented method can

  16. Mid infrared emission spectroscopy of carbon plasma.

    PubMed

    Nemes, Laszlo; Brown, Ei Ei; S-C Yang, Clayton; Hommerich, Uwe

    2017-01-01

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results.

  17. Mid infrared emission spectroscopy of carbon plasma.

    PubMed

    Nemes, Laszlo; Brown, Ei Ei; S-C Yang, Clayton; Hommerich, Uwe

    2017-01-01

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results. PMID:27428600

  18. Development of secondary cell wall in cotton fibers as examined with Fourier transform-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our presentation will focus on continuing efforts to examine secondary cell wall development in cotton fibers using infrared Spectroscopy. Cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering were examined using attenuated total reflection Fourier transform-infrared (ATR FT-...

  19. Time resolved spectroscopy using synchrotron infrared pulses

    SciTech Connect

    Carr, G.L.; Lobo, R.P.S.M. |; Hirschmugl, C.J.; LaVeigne, J.; Reitze, D.H.; Tanner, D.B.

    1997-09-01

    Electron synchrotron storage rings, such as the VUV ring at the National Synchrotron Light Source (NSLS), produce short pulses of infrared (IR) radiation suitable for investigating the time-dependent phenomena in a variety of interesting experimental systems. In contrast to other pulses sources of IR, the synchrotron produces a continuum spectral output over the entire IR (and beyond), though at power levels typically below those obtained from laser systems. The infrared synchrotron radiation (IRSR) source is therefore well-suited as a probe using standard FTIR spectroscopic techniques. Here the authors describe the pump-probe spectroscopy facility being established at the NSLS and demonstrate the technique by measuring the photocarrier decay in a semiconductor.

  20. Drill hole logging with infrared spectroscopy

    USGS Publications Warehouse

    Calvin, W.M.; Solum, J.G.

    2005-01-01

    Infrared spectroscopy has been used to identify rocks and minerals for over 40 years. The technique is sensitive to primary silicates as well as alteration products. Minerals can be uniquely identified based on multiple absorption features at wavelengths from the visible to the thermal infrared. We are currently establishing methods and protocols in order to use the technique for rapid assessment of downhole lithology on samples obtained during drilling operations. Initial work performed includes spectral analysis of chip cuttings and core sections from drill sites around Desert Peak, NV. In this paper, we report on a survey of 10,000 feet of drill cuttings, at 100 foot intervals, from the San Andreas Fault Observatory at Depth (SAFOD). Data from Blue Mountain geothermal wells will also be acquired. We will describe the utility of the technique for rapid assessment of lithologic and mineralogic discrimination.

  1. Infrared Spectroscopy of Anhydrous Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Flynn, G. J.

    2003-01-01

    Infrared (IR) spectroscopy is the primary means of mineralogical analysis of materials outside our solar system. The identity and properties of circumstellar grains are inferred from spectral comparisons between astronomical observations and laboratory data from natural and synthetic materials. These comparisons have been facilitated by the Infrared Space Observatory (ISO), which obtained IR spectra from numerous astrophysical objects over a wide spectral range (out to 50/cm) where crystalline silicates and other phases have distinct features. The anhydrous interplanetary dust particles (IDPs) are particularly important comparison materials because some IDPs contain carbonaceous material with non-solar D/H and N-15/N-14 ratios and amorphous and crystalline silicates with non-solar 0- isotopic ratios, demonstrating that these IDPs contain preserved interstellar material. Here, we report on micro- Fourier transform (FT) IR spectrometry of IDPs, focusing on the inorganic components of primitive IDPs (FTIR spectra from the organic/carbonacecous materials in IDPs are described elsewhere).

  2. Fourier transform infrared spectroscopy for Mars science

    NASA Astrophysics Data System (ADS)

    Anderson, Mark S.; Andringa, Jason M.; Carlson, Robert W.; Conrad, Pamela; Hartford, Wayne; Shafer, Michael; Soto, Alejandro; Tsapin, Alexandre I.; Dybwad, Jens Peter; Wadsworth, Winthrop; Hand, Kevin

    2005-03-01

    Presented here is a Fourier transform infrared spectrometer (FTIR) for field studies that serves as a prototype for future Mars science applications. Infrared spectroscopy provides chemical information that is relevant to a number of Mars science questions. This includes mineralogical analysis, nitrogen compound recognition, truth testing of remote sensing measurements, and the ability to detect organic compounds. The challenges and scientific opportunities are given for the in situ FTIR analysis of Mars soil and rock samples. Various FTIR sampling techniques are assessed and compared to other analytical instrumentation. The prototype instrument presented is capable of providing field analysis in a Mars analog Antarctic environment. FTIR analysis of endolithic microbial communities in Antarctic rocks and a Mars meteor are given as analytical examples.

  3. Detection of Endolithes Using Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dumas, S.; Dutil, Y.; Joncas, G.

    2009-12-01

    On Earth, the Dry Valleys of Antarctica provide the closest martian-like environment for the study of extremophiles. Colonies of bacterias are protected from the freezing temperatures, the drought and UV light. They represent almost half of the biomass of those regions. Due to their resilience, endolithes are one possible model of martian biota. We propose to use infrared spectroscopy to remotely detect those colonies even if there is no obvious sign of their presence. This remote sensing approach reduces the risk of contamination or damage to the samples.

  4. Infrared spectroscopy study of irradiated PVDF

    SciTech Connect

    Chappa, Veronica; Grosso, Mariela del; Garcia Bermudez, Gerardo; Behar, Moni

    2007-10-26

    The effects induced by 1 MeV/amu ion irradiations were compared to those induced by 4-12 MeV/amu irradiations. Structural analysis with infrared spectroscopy (FTIR) was carried out on PVDF irradiated using C and He beams with different fluences. From these spectra it was observed, as a function of fluence, an overall destruction of the polymer, amorphization of the crystalline regions and the creation of in-chain unsaturations. The track dimensions were determined using a previously developed Monte Carlo simulation code and these results were compared to a semiempirical model.

  5. Dispersion effects on infrared spectra in attenuated total reflection

    NASA Astrophysics Data System (ADS)

    Belali, Rabah; Vigoureux, Jean-Marie; Morvan, Joseph

    1995-12-01

    A potential problem with the attenuated total reflection that is used to measure infrared spectra is described. The problem is the possibility that the anomalous dispersion associated with an infrared absorption band may cause the experimental configuration to move from the attenuated total reflection regime to the specular reflection regime, with consequent distortion of the apparent absorption bands and consequent error in the interpretation of the bands if the problem is not recognized. Key infrared spectra, attenuated total reflection, specular reflection, polyethylene terephtalate. Copyright (c) 1995 Optical Society of America

  6. Near-infrared spectroscopy for plaque characterization.

    PubMed

    Waxman, Sergio

    2008-12-01

    A near-infrared (NIR) spectroscopy catheter-based system has been developed for intracoronary detection of lipid-rich plaques, capable of scanning an artery through blood and during cardiac motion. The lipid-rich plaque chemometric algorithm was validated in an ex vivo study using coronary artery specimens from autopsy hearts. A parallel clinical study was performed to demonstrate safety of the system in patients and the similarity of spectra acquired in vivo to data from the ex vivo study. Proof of spectral similarity between data obtained in patients and data from autopsy specimens is required to demonstrate the applicability of the algorithm to patients, in whom tissue for analysis is not available. A preliminary analysis in an unblinded cohort of patients from the clinical study reported promising results. The final results of the clinical study will be submitted for publication. The potential clinical value of this NIR spectroscopy device is discussed.

  7. Infrared microcalorimetric spectroscopy using quantum cascade lasers

    SciTech Connect

    Morales Rodriguez, Marissa E; Senesac, Larry R; Rajic, Slobodan; Lavrik, Nickolay V; Smith, Barton; Datskos, Panos G

    2013-01-01

    We have investigated an infrared (IR) microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the IR photothermal spectra of molecules absorbed on the surface of uncooled thermal micromechanical detectors. IR microcalorimetric spectroscopy requires no chemical specific coatings and the chemical specificity of the presented method is a consequence of the wavelength-specific absorption of IR photons from tunable quantum cascade lasers due to vibrational spectral bands of the analyte. We have obtained IR photothermal spectra for trace concentrations of RDX and a monolayer of 2-mercaptoethanol, over the wavelength region from 6 to 10 m. We found that in this wavelength region both chemicals exhibit a number of photothermal absorption features that are in good agreement with their respective IR spectra.

  8. Disease recognition by infrared and Raman spectroscopy.

    PubMed

    Krafft, Christoph; Steiner, Gerald; Beleites, Claudia; Salzer, Reiner

    2009-02-01

    Infrared (IR) and Raman spectroscopy are emerging biophotonic tools to recognize various diseases. The current review gives an overview of the experimental techniques, data-classification algorithms and applications to assess soft tissues, hard tissues and body fluids. The methodology section presents the principles to combine vibrational spectroscopy with microscopy, lateral information and fiber-optic probes. A crucial step is the classification of spectral data by a variety of algorithms. We discuss unsupervised algorithms such as cluster analysis or principal component analysis and supervised algorithms such as linear discriminant analysis, soft independent modeling of class analogies, artificial neural networks support vector machines, Bayesian classification, partial least-squares regression and ensemble methods. The selected topics include tumors of epithelial tissue, brain tumors, prion diseases, bone diseases, atherosclerosis, kidney stones and gallstones, skin tumors, diabetes and osteoarthritis.

  9. Infrared spectroscopy of self-assembled monolayer films on silicon

    NASA Astrophysics Data System (ADS)

    Rowell, N. L.; Tay, Lilin; Boukherroub, R.; Lockwood, D. J.

    2007-07-01

    Infrared vibrational spectroscopy in an attenuated total reflection (ATR) geometry has been employed to investigate the presence of organic thin layers on Si-wafer surfaces. The phenomena have been simulated to show there can be a field enhancement with the presented single-reflection ATR (SR-ATR) approach which is substantially larger than for conventional ATR or specular reflection. In SR-ATR, a discontinuity of the field normal to the film contributes a field enhancement in the lower index thin film causing a two order of magnitude increase in sensitivity. SR-ATR was employed to characterize a single monolayer of undecylenic acid self-assembled on Si(1 1 1) and to investigate a two monolayer system obtained by adding a monolayer of bovine serum albumin protein.

  10. Soft tissue differentiation by diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Zam, Azhar; Stelzle, Florian; Nkenke, Emeka; Tangermann-Gerk, Katja; Schmidt, Michael; Adler, Werner; Douplik, Alexandre

    2009-07-01

    Laser surgery gives the possibility to work remotely which leads to high precision, little trauma and high level sterility. However these advantages are coming with the lack of haptic feedback during the laser ablation of tissue. Therefore additional means are required to control tissue-specific ablation during laser surgery supporting the surgeon regardless of experience and skills. Diffuse Reflectance Spectroscopy provides a straightforward and simple approach for optical tissue differentiation. We measured diffuse reflectance from four various tissue types ex vivo. We applied Linear Discriminant Analysis (LDA) to differentiate the four tissue types and computed the area under the ROC curve (AUC). Special emphasis was taken on the identification of nerve as the most crucial tissue for maxillofacial surgery. The results show a promise for differentiating soft tissues as guidance for tissue-specific laser surgery by means of the diffuse reflectance.

  11. Infrared spectroscopy of mass-selected carbocations

    SciTech Connect

    Duncan, Michael A.

    2015-01-22

    Small carbocations are of longstanding interest in astrophysics, but there are few measurements of their infrared spectroscopy in the gas phase at low temperature. There are fewer-still measurements of spectra across the full range of IR frequencies useful to obtain an IR signature of these ions to detect them in space. We have developed a pulsed-discharge supersonic nozzle ion source producing high densities of small carbocations at low temperatures (50–70K). We employ mass-selected photodissociation spectroscopy and the method of rare gas “tagging”, together with new broadly tunable infrared OPO lasers, to obtain IR spectra for a variety of small carbocations including C{sub 2}H{sub 3}{sup +}, C{sub 3}H{sub 3}{sup +}, C{sub 3}H{sub 5}{sup +}, protonated benzene and protonated naphthalene. Spectra in the frequency range of 600–4500 cm{sup −1} provide new IR data for these ions and evidence for the presence of co-existing isomeric structures (e.g., C{sub 3}H{sub 3}{sup +} is present as both cyclopropenyl and propargyl). Protonated naphthalene has sharp bands at 6.2, 7.7 and 8.6 microns matching prominent features in the UIR spectra.

  12. Infrared Spectroscopy as a Chemical Fingerprinting Tool

    NASA Technical Reports Server (NTRS)

    Huff, Timothy L.

    2003-01-01

    Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. Any sample material that will interact with infrared light produces a spectrum and, although normally associated with organic materials, inorganic compounds may also be infrared active. The technique is rapid, reproducible and usually non-invasive to the sample. That it is non-invasive allows for additional characterization of the original material using other analytical techniques including thermal analysis and RAMAN spectroscopic techniques. With the appropriate accessories, the technique can be used to examine samples in liquid, solid or gas phase. Both aqueous and non-aqueous free-flowing solutions can be analyzed, as can viscous liquids such as heavy oils and greases. Solid samples of varying sizes and shapes may also be examined and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be analyzed. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

  13. Nanostructured diamond layers enhance the infrared spectroscopy of biomolecules.

    PubMed

    Kozak, Halyna; Babchenko, Oleg; Artemenko, Anna; Ukraintsev, Egor; Remes, Zdenek; Rezek, Bohuslav; Kromka, Alexander

    2014-03-01

    We report on the fabrication and practical use of high-quality optical elements based on Au mirrors coated with diamond layers with flat, nanocolumnar, and nanoporous morphologies. Diamond layers (100 nm thickness) are grown at low temperatures (about 300 °C) from a methane, carbon dioxide, and hydrogen gas mixture by a pulsed microwave plasma system with linear antennas. Using grazing angle reflectance (GAR) Fourier transform infrared spectroscopy with p-polarized light, we compare the IR spectra of fetal bovine serum proteins adsorbed on diamond layers with oxidized (hydrophilic) surfaces. We show that the nanoporous diamond layers provide IR spectra with a signal gain of about 600% and a significantly improved sensitivity limit. This is attributed to its enhanced internal surface area. The improved sensitivity enabled us to distinguish weak infrared absorption peaks of <10-nm-thick protein layers and thereby to analyze the intimate diamond-molecule interface.

  14. Measuring cloud thermodynamic phase with shortwave infrared imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Thompson, David R.; McCubbin, Ian; Gao, Bo Cai; Green, Robert O.; Matthews, Alyssa A.; Mei, Fan; Meyer, Kerry G.; Platnick, Steven; Schmid, Beat; Tomlinson, Jason; Wilcox, Eric

    2016-08-01

    Shortwave Infrared imaging spectroscopy enables accurate remote mapping of cloud thermodynamic phase at high spatial resolution. We describe a measurement strategy to exploit signatures of liquid and ice absorption in cloud top apparent reflectance spectra from 1.4 to 1.8 μm. This signal is generally insensitive to confounding factors such as solar angles, view angles, and surface albedo. We first evaluate the approach in simulation and then apply it to airborne data acquired in the Calwater-2/ACAPEX campaign of Winter 2015. Here NASA's "Classic" Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) remotely observed diverse cloud formations while the U.S. Department of Energy ARM Aerial Facility G-1 aircraft measured cloud integral and microphysical properties in situ. The coincident measurements demonstrate good separation of the thermodynamic phases for relatively homogeneous clouds.

  15. [Application of infrared spectroscopy technique to discrimination of alcoholic beverages].

    PubMed

    Niu, Xiao-Ying; Ying, Yi-Bin; Yu, Hai-Yan; Xie, Li-Juan; Fu, Xia-Ping

    2008-04-01

    Infrared spectroscopy technique is a rapid for the discrimination of food samples, and is widely used to detect and discriminate various beverages. This paper presents the advantages and disadvantages of techniques that have been used to discriminate alcoholic beverages, and the discriminating procedure with infrared spectroscopy technique. Applications of infrared spectroscopy technique to wine, whiskey, Japanese sake and Chinese rice wine etc. is presented too. Finally, problems in applications are analyzed, and the application of infrared spectroscopy technique to the discrimination of our traditional alcoholic beverages is prospected. PMID:18619303

  16. Infrared-Bolometer Arrays with Reflective Backshorts

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Abrahams, John; Allen, Christine A.

    2011-01-01

    Integrated circuits that incorporate square arrays of superconducting-transition- edge bolometers with optically reflective backshorts are being developed for use in image sensors in the spectral range from far infrared to millimeter wavelengths. To maximize the optical efficiency (and, thus, sensitivity) of such a sensor at a specific wavelength, resonant optical structures are created by placing the backshorts at a quarter wavelength behind the bolometer plane. The bolometer and backshort arrays are fabricated separately, then integrated to form a single unit denoted a backshort-under-grid (BUG) bolometer array. In a subsequent fabrication step, the BUG bolometer array is connected, by use of single-sided indium bump bonding, to a readout device that comprises mostly a superconducting quantum interference device (SQUID) multiplexer circuit. The resulting sensor unit comprising the BUG bolometer array and the readout device is operated at a temperature below 1 K. The concept of increasing optical efficiency by use of backshorts at a quarter wavelength behind the bolometers is not new. Instead, the novelty of the present development lies mainly in several features of the design of the BUG bolometer array and the fabrication sequence used to implement the design. Prior to joining with the backshort array, the bolometer array comprises, more specifically, a square grid of free-standing molybdenum/gold superconducting-transition-edge bolometer elements on a 1.4- m-thick top layer of silicon that is part of a silicon support frame made from a silicon-on-insulator wafer. The backshort array is fabricated separately as a frame structure that includes support beams and contains a correspond - ing grid of optically reflective patches on a single-crystal silicon substrate. The process used to fabricate the bolometer array includes standard patterning and etching steps that result in the formation of deep notches in the silicon support frame. These notches are designed to

  17. Triggered infrared spectroscopy for investigating metalloprotein chemistry.

    PubMed

    Vincent, Kylie A

    2010-08-13

    Recent developments in infrared (IR) spectroscopic time resolution, sensitivity and sample manipulation make this technique a powerful addition to the suite of complementary approaches for the study of time-resolved chemistry at metal centres within proteins. Application of IR spectroscopy to proteins has often targeted the amide bands as probes for gross structural change. This article focuses on the possibilities arising from recent IR technical developments for studies that monitor localized vibrational oscillators in proteins--native or exogenous ligands such as NO, CO, SCN(-) or CN(-), or genetically or chemically introduced probes with IR-active vibrations. These report on the electronic and coordination state of metals, the kinetics, intermediates and reaction pathways of ligand release, hydrogen-bonding interactions between the protein and IR probe, and the electrostatic character of sites in a protein. Metalloprotein reactions can be triggered by light/dark transitions, an electrochemical step, a change in solute composition or equilibration with a new gas atmosphere, and spectra can be obtained over a range of time domains as far as the sub-picosecond level. We can expect to see IR spectroscopy exploited, alongside other spectroscopies, and crystallography, to elucidate reactions of a wide range of metalloprotein chemistry with relevance to cell metabolism, health and energy catalysis.

  18. Visualizing Infrared (IR) Spectroscopy with Computer Animation

    NASA Technical Reports Server (NTRS)

    Abrams, Charles B.; Fine, Leonard W.

    1996-01-01

    IR Tutor, an interactive, animated infrared (IR) spectroscopy tutorial has been developed for Macintosh and IBM-compatible computers. Using unique color animation, complicated vibrational modes can be introduced to beginning students. Rules governing the appearance of IR absorption bands become obvious because the vibrational modes can be visualized. Each peak in the IR spectrum is highlighted, and the animation of the corresponding normal mode can be shown. Students can study each spectrum stepwise, or click on any individual peak to see its assignment. Important regions of each spectrum can be expanded and spectra can be overlaid for comparison. An introduction to the theory of IR spectroscopy is included, making the program a complete instructional package. Our own success in using this software for teaching and research in both academic and industrial environments will be described. IR Tutor consists of three sections: (1) The 'Introduction' is a review of basic principles of spectroscopy. (2) 'Theory' begins with the classical model of a simple diatomic molecule and is expanded to include larger molecules by introducing normal modes and group frequencies. (3) 'Interpretation' is the heart of the tutorial. Thirteen IR spectra are analyzed in detail, covering the most important functional groups. This section features color animation of each normal mode, full interactivity, overlay of related spectra, and expansion of important regions. This section can also be used as a reference.

  19. Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1995-01-01

    A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straight-forwardly be quantitatively integrated over the angular aperture without considering non-uniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

  20. Analysis of remote reflection spectroscopy to monitor plant health

    NASA Astrophysics Data System (ADS)

    Woodhouse, R.; Heeb, M.; Berry, W.; Hoshizaki, T.; Wood, M.

    1994-11-01

    Remote non-contact reflection spectroscopy is examined as a method for detecting stress in Controlled Ecological Life Support System CELSS type crops. Lettuce (Latuca Sativa L. cv. Waldmans Green) and wheat (Triticum Aestivum L. cv. Yecora Rojo) were grown hydroponically. Copper and zinc treatments provided toxic conditions. Nitrogen, phosphorous, and potassium treatments were used for deficiency conditions. Water stress was also induced in test plants. Reflectance spectra were obtained in the visible and near infrared (400nm to 2600nm) wavebands. Numerous effects of stress conditions can be observed in the collected spectra and this technique appears to have promise as a remote monitor of plant health, but significant research remains to be conducted to realize the promise.

  1. Analysis of remote reflection spectroscopy to monitor plant health.

    PubMed

    Woodhouse, R; Heeb, M; Berry, W; Hoshizaki, T; Wood, M

    1994-11-01

    Remote non-contact reflection spectroscopy is examined as a method for detecting stress in Controlled Ecological Life Support System CELSS type crops. Lettuce (Lactuca [correction of Latuca] Sativa L. cv. Waldmans Green) and wheat (Triticum Aestivum L. cv. Yecora Rojo) were grown hydroponically. Copper and zinc treatments provided toxic conditions. Nitrogen, phosphorous, and potassium treatments were used for deficiency conditions. Water stress was also induced in test plants. Reflectance spectra were obtained in the visible and near infrared (400nm to 2600nm) wavebands. Numerous effects of stress conditions can be observed in the collected spectra and this technique appears to have promise as a remote monitor of plant health, but significant research remains to be conducted to realize the promise. PMID:11540181

  2. Light distribution modulated diffuse reflectance spectroscopy.

    PubMed

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-06-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation. PMID:27375931

  3. Light distribution modulated diffuse reflectance spectroscopy

    PubMed Central

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-01-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation. PMID:27375931

  4. Cardiac tissue characterization using near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Singh Moon, Rajinder; Hendon, Christine P.

    2014-03-01

    Cardiac tissue from swine and canine hearts were assessed using diffuse reflectance near-infrared spectroscopy (NIRS) ex vivo. Slope measured between 800-880 nm reflectance was found to reveal differences between epicardial fat and normal myocardium tissue. This parameter was observed to increase monotonically from measurements obtained from the onset of radiofrequency ablation (RFA). A sheathe-style fiber optic catheter was then developed to allow real-time sampling of the zone of resistive heating during RFA treatment. A model was developed and used to extract changes in tissue absorption and reduced scattering based on the steady-state diffusion approximation. It was found that key changes in tissue optical properties occur during application of RF energy and can be monitored using NIRS. These results encourage the development of NIRS integrated catheters for real-time guidance of the cardiac ablation treatment.

  5. Buccal microbiology analyzed by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    de Abreu, Geraldo Magno Alves; da Silva, Gislene Rodrigues; Khouri, Sônia; Favero, Priscila Pereira; Raniero, Leandro; Martin, Airton Abrahão

    2012-01-01

    Rapid microbiological identification and characterization are very important in dentistry and medicine. In addition to dental diseases, pathogens are directly linked to cases of endocarditis, premature delivery, low birth weight, and loss of organ transplants. Fourier Transform Infrared Spectroscopy (FTIR) was used to analyze oral pathogens Aggregatibacter actinomycetemcomitans ATCC 29523, Aggregatibacter actinomycetemcomitans-JP2, and Aggregatibacter actinomycetemcomitans which was clinically isolated from the human blood-CI. Significant spectra differences were found among each organism allowing the identification and characterization of each bacterial species. Vibrational modes in the regions of 3500-2800 cm-1, the 1484-1420 cm-1, and 1000-750 cm-1 were used in this differentiation. The identification and classification of each strain were performed by cluster analysis achieving 100% separation of strains. This study demonstrated that FTIR can be used to decrease the identification time, compared to the traditional methods, of fastidious buccal microorganisms associated with the etiology of the manifestation of periodontitis.

  6. [Study on the soil mid-infrared photoacoustic spectroscopy].

    PubMed

    Du, Chang-wen; Zhou, Jian-min; Wang, Huo-yan; Zhang, Jia-bao; Zhu, An-ning

    2008-06-01

    Infrared photoacoustic spectroscopy (PAS) is a new style to obtain data based on photoacoustic theory. Photoacoustic thoeory is based on the absorption of electromagnetic radiation by analyte molecules, and the absorbed energy is measured by detecting pressure fluctuations in the form of sound waves or shock pulses. In contrast to conventional absorption spectroscopy, PAS allows the determination of absorption coefficients over several orders of magnitude, even in very black and strongly scattering soil samples. Red soil, fulvic soil and paddy soil were collected from Fengqiu National Ecological Experimental Station, Yingtan Red Soil Experimental Station, and Changshu Ecological Experimental Station, respectively. These soil samples were used as experimental materials to characterize the Fourier transform mid-infrared photoacoustic spectra (FTIR-PAS). Compared with infrared transmittance spectra and reflectance spectra, the testing of FTIR-PAS spectra was very fast and convenient without any pr-treatment, and there were more abundant absorptions as well as appropriate absorption values in the spectra; The main soil components (kaolin, bentonite, sand and CaCO3) also showed several strong absorptions with specific characteristics in the spectra; Further more, the interference of water with the PAS spectra was significantly smaller than that with reflectance spectra. Therefore, the soil properties could be better characterized by FTIR-PAS. The principal components analysis based on the FTIR-PAS spectra indicated that there were two main principal components (PCA1, PCA2) which contained 98.17% variance of the spectra, and the two-dimensionol distribution was made by plotting these two principal components to classify the soil type, and the results indicated that this distribution could be applied to distinguish soil type, which provided new technique for soil identification as well as further quantitative analysis in soil science.

  7. Characterizing Aeroallergens by Infrared Spectroscopy of Fungal Spores and Pollen

    PubMed Central

    Zimmermann, Boris; Tkalčec, Zdenko; Mešić, Armin; Kohler, Achim

    2015-01-01

    Background Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens. Methodology The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR). The experimental set includes 71 spore (Basidiomycota) and 121 pollen (Pinales, Fagales and Poales) samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years. Results The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps. PMID:25867755

  8. Indirect absorption spectroscopy using quantum cascade lasers: mid-infrared refractometry and photothermal spectroscopy.

    PubMed

    Pfeifer, Marcel; Ruf, Alexander; Fischer, Peer

    2013-11-01

    We record vibrational spectra with two indirect schemes that depend on the real part of the index of refraction: mid-infrared refractometry and photothermal spectroscopy. In the former, a quantum cascade laser (QCL) spot is imaged to determine the angles of total internal reflection, which yields the absorption line via a beam profile analysis. In the photothermal measurements, a tunable QCL excites vibrational resonances of a molecular monolayer, which heats the surrounding medium and changes its refractive index. This is observed with a probe laser in the visible. Sub-monolayer sensitivities are demonstrated.

  9. Quantitative determination of two polymorphic forms of imatinib mesylate in a drug substance and tablet formulation by X-ray powder diffraction, differential scanning calorimetry and attenuated total reflectance Fourier transform infrared spectroscopy.

    PubMed

    Bellur Atici, Esen; Karlığa, Bekir

    2015-10-10

    Imatinib has been identified as a tyrosine kinase inhibitor that selectively inhibits the Abl tyrosine kinases, including Bcr-Abl. The active substance used in drug product is the mesylate salt form of imatinib, a phenylaminopyrimidine derivative and chemically named as N-(3-(4-(pyridin-3-yl) pyrimidin-2-ylamino)-4-methylphenyl)-4-((4-methylpiperazin-1-yl) methyl)-benzamide methanesulfonic acid salt. It exhibits many polymorphic forms and most stable and commercialized polymorphs are known as α and β forms. Molecules in α and β polymorphic forms exhibit significant conformational differences due to their different intra- and intermolecular interactions, which stabilize their molecular conformations and affect their physicochemical properties such as bulk density, melting point, solubility, stability, and processability. The manufacturing process of a drug tablet included granulation, compression, coating, and drying may cause polymorphic conversions. Therefore, polymorphic content of the drug substance should be controlled during quality control and stability testing. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) methods were evaluated for determination of the polymorphic content of the drug substance and drug product; and PXRD was the most accurate technique and selected as preferred method and validated. Prior to development of a quantification method, pure α and β polymorphs were characterized and used throughout the method development and validation studies. Mixtures with different ratios of α and β forms were scanned using X-ray diffractometer with a scan rate of 0.250°/min over an angular range of 19.5-21.0° 2θ and the peak heights for characteristic peak of β form at 20.5 ± 0.2° 2θ diffraction angle were used to generate a calibration curve. The detection limit of β polymorph in α form imatinib mesylate tablets was found as 4% and

  10. PREFACE: 3rd International Workshop on Infrared Plasma Spectroscopy

    NASA Astrophysics Data System (ADS)

    Davies, P. B.; Röpcke, Jürgen; Hempel, Frank

    2009-07-01

    This volume containsd a selection of papers from the third Infrared Plasma Spectroscopy (IPS) Workshop held in Greifswald, Germany in July 2008. Although not all the contributions have been written up in time for the deadline for this volume, nevertheless the 12 contributions presented here give a fair representation of the conference topics. The conference comprised four different types of contribution. Firstly, four invited lectures focussed on the prime areas of interest. Secondly, eight shorter contributed talks, grouped as closely as possible with the appropriate invited lecture. These contributed talks covered topics in both pure and applied infrared plasma spectroscopy. A feature of the two previous IPS conferences has been a contribution from commercial organisations namely those involved in manufacturing devices, detectors and spectrometers. This group of participants formed the third part of the conference programme and gave five oral presentations covering topics like QCL and detector/detection developments and novel spectrometer designs. The fourth contributing group comprised 27 poster presentations. It should be mentioned that some of the latter were poster versions of contributed talks. The conference was remarkable for the wide spread of topics covered in a relatively small meeting, consisting of 44 participants. The participants were made up of 34 scientists from within Europe and 4 from the rest of the world. It is interesting to reflect on changes that have occurred since the previous meeting just a year earlier. Two clear developments which have occurred are the emergence of Quantum Cascade Lasers (QCL) and their use in Cavity Ring Down (CRD) spectroscopy. A major shift from cw lead salt diode lasers to cw and pulsed QCL in both pure and applied projects now seems to be well under way. The topics covered in the earlier conferences focussed more on applying infrared spectroscopy to plasma monitoring and control. When choosing the topics to cover

  11. Optical Reflection Spectroscopy of GEO Objects

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Cardona, Tammaso; Lederer, Susan M.; Cowardin, Heather; Abercromby, Kira J.; Barker, Edwin S.; Bedard, Donald

    2013-01-01

    We report on optical reflection spectroscopy of geosynchronous (GEO) objects in the US Space Surveillance Network (SSN) catalog. These observations were obtained using imaging spectrographs on the 6.5-m Magellan telescopes at the Las Campanas Observatory in Chile. Our goal is to determine the composition of these objects by comparing these spectral observations with ground-based laboratory measurements of spacecraft materials. The observations are all low resolution (1 nm after smoothing) obtained through a 5 arcsecond wide slit and using a grism as the dispersing element. The spectral range covered was from 450 nm to 800 nm. All spectra were flux calibrated using observations of standard stars with the exact same instrumental setup. An effort was made to obtain all observations within a limited range of topocentric phase angle, although the solar incident angle is unknown due to the lack of any knowledge of the attitude of the observed surface at the time of observation.

  12. Reflectance spectroscopy of organic compounds: 1. Alkanes

    USGS Publications Warehouse

    Clark, R.N.; Curchin, J.M.; Hoefen, T.M.; Swayze, G.A.

    2009-01-01

    Reflectance spectra of the organic compounds comprising the alkane series are presented from the ultraviolet to midinfrared, 0.35 to 15.5 /??m. Alkanes are hydrocarbon molecules containing only single carbon-carbon bonds, and are found naturally on the Earth and in the atmospheres of the giant planets and Saturn's moon, Titan. This paper presents the spectral properties of the alkanes as the first in a series of papers to build a spectral database of organic compounds for use in remote sensing studies. Applications range from mapping the environment on the Earth, to the search for organic molecules and life in the solar system and throughout the. universe. We show that the spectral reflectance properties of organic compounds are rich, with major diagnostic spectral features throughout the spectral range studied. Little to no spectral change was observed as a function of temperature and only small shifts and changes in the width of absorption bands were observed between liquids and solids, making remote detection of spectral properties throughout the solar system simpler. Some high molecular weight organic compounds contain single-bonded carbon chains and have spectra similar to alkanes even ' when they fall into other families. Small spectral differences are often present allowing discrimination among some compounds, further illustrating the need to catalog spectral properties for accurate remote sensing identification with spectroscopy.

  13. Multiple peak reference method for polarized Fourier transform infrared-attenuated total reflection spectroscopy to determine the three-dimensional orientation of a uniaxially drawn poly(trimethylene 2,6-naphthalate) film.

    PubMed

    Liang, Yongri; Choi, Ki Woon; Lee, Han Sup

    2008-12-01

    The polarized Fourier transform infrared-attenuated total reflection (FT-IR-ATR) technique is a very useful infrared spectroscopic method for characterizing the three-dimensional orientation of thick samples, to which the conventional transmission FT-IR method cannot easily be applied. To quantitatively analyze polarized FT-IR-ATR spectra, the dependence of the optical contact between the sample and the ATR crystal during the clamping and reclamping processes must be controlled. In this work, a new multiple peak reference (MPR) method is proposed and used to carry out a three-dimensional analysis of a poly(trimethylene 2,6-naphthalate) (PTN) polymer sample. The conventional single peak reference (SPR) analysis technique cannot be applied to such a sample due to the lack of an established reference peak. A new artificial reference band was generated by the MPR method using two different infrared bands, at 1602 cm(-1) and 917 cm(-1), in identical spectra with a combination constant of 0.95. The new artificial reference band was successfully used to calculate the three-dimensional orientation of various infrared bands of a uniaxially drawn PTN film, which has not previously been studied by three-dimensional orientation analyses using the polarized FT-IR-ATR method.

  14. Infrared studies of dust grains in infrared reflection nebulae

    NASA Technical Reports Server (NTRS)

    Pendleton, Yvonne J.; Tielens, Alexander G. G. M.; Werner, Michael W.

    1989-01-01

    IR reflection nebulae, regions of dust which are illuminated by nearby embedded sources, were observed in several regions of ongoing star formation. Near IR observation and theoretical modelling of the scattered light form IR reflection nebulae can provide information about the dust grain properties in star forming regions. IR reflection nebulae were modelled as plane parallel slabs assuming isotropically scattering grains. For the grain scattering properties, graphite and silicate grains were used with a power law grain size distribution. Among the free parameters of the model are the stellar luminosity and effective temperature, the optical depth of the nebula, and the extinction by foreground material. The typical results from this model are presented and discussed.

  15. Localized photothermal infrared spectroscopy using a proximal probe

    NASA Astrophysics Data System (ADS)

    Bozec, L.; Hammiche, A.; Pollock, H. M.; Conroy, M.; Chalmers, J. M.; Everall, N. J.; Turin, L.

    2001-11-01

    A near-field thermal probe, as used in scanning thermal microscopy, is used to obtain photothermal Fourier transform infrared (FT-IR) spectra of polymers, as a first step toward developing FT-IR microscopy at a spatial resolution better than the diffraction limit. The signal from the probe after amplification provides an interferogram, and the resultant spectra are consistent with those obtained by means of the established technique of attenuated total reflection FT-IR spectroscopy. We have extended this technique to the analysis of "real-world" industrial samples, both solid (a fungicide in a fine powder form) and liquid (a concentrated surfactant solution). The overall shapes of the main peaks or bands reflect the fact that the spectrum is a convolution of different contributions from both optical and thermal properties. To confirm the feasibility of subsurface detection of polymers, we demonstrate the ability of the technique to perform spectroscopic detection of a model polymeric bilayer system, polyisobutylene on top of polystyrene. A quantitative analysis of the variation of peak height with coating thickness allows values of thermal diffusion length to be derived. This investigation provides a preliminary result for the understanding of the depth sensitivity of the current setup. Relative intensity distortions are seen, and are attributed to photothermal saturation. A complementary technique has been developed that uses tunable monochromatic radiation, using an optical parametric generator as the infrared source. Spectra have successfully been obtained using the same localized photothermal detection principle.

  16. Fourier Transform Infrared Spectroscopy and Photoacoustic Spectroscopy for Saliva Analysis.

    PubMed

    Mikkonen, Jopi J W; Raittila, Jussi; Rieppo, Lassi; Lappalainen, Reijo; Kullaa, Arja M; Myllymaa, Sami

    2016-09-01

    Saliva provides a valuable tool for assessing oral and systemic diseases, but concentrations of salivary components are very small, calling the need for precise analysis methods. In this work, Fourier transform infrared (FT-IR) spectroscopy using transmission and photoacoustic (PA) modes were compared for quantitative analysis of saliva. The performance of these techniques was compared with a calibration series. The linearity of spectrum output was verified by using albumin-thiocyanate (SCN(-)) solution at different SCN(-) concentrations. Saliva samples used as a comparison were obtained from healthy subjects. Saliva droplets of 15 µL were applied on the silicon sample substrate, 6 drops for each specimen, and dried at 37 ℃ overnight. The measurements were carried out using an FT-IR spectrometer in conjunction with an accessory unit for PA measurements. The findings with both transmission and PA modes mirror each other. The major bands presented were 1500-1750 cm(-1) for proteins and 1050-1200 cm(-1) for carbohydrates. In addition, the distinct spectral band at 2050 cm(-1) derives from SCN(-) anions, which is converted by salivary peroxidases to hypothiocyanate (OSCN(-)). The correlation between the spectroscopic data with SCN(-) concentration (r > 0.990 for transmission and r = 0.967 for PA mode) was found to be significant (P < 0.01), thus promising to be utilized in future applications.

  17. Development of Noninvasive Blood Glucose Sensor Using the Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fujita, Keiichi; Tamura, Kazuto; Kaneko, Wataru; Ishizawa, Hiroaki; Toba, Eiji

    Recently, diabetics have been steadily increasing, because change of diet, lack of exercise, increase an alcoholic intake, and increase a stress. It is a very serious problem for us. About 23.6 millions of people in Japan approach the danger of diabetes. Therefore, it is necessary to get insulin injection. And they have to measure blood glucose again and again a day. So, they are burden too heavy. This paper describes a new noninvasive measurement of blood glucose based on optical sensing. This uses Fourier transform infrared spectroscopy of attenuated total reflection. Non-invasive measurement was carried out by using 3 methods. And standard error of prediction is about ±20mg/dl by 3 method. This paper also describes practical application of this method.

  18. Near-infrared spectroscopy for personal screening

    NASA Astrophysics Data System (ADS)

    Canal, Céline M.; Saleem, Aamer; Green, Roger J.; Hutchins, David A.

    2010-10-01

    This paper will demonstrate that near infrared (NIR) signals at wavelengths in the range 0.9 to 2.5 microns can be used for personal screening applications. At these wavelengths, there is sufficient spectral information to provide chemical identification, while still providing transmission through many types of common clothing materials. Thus, chemical identification in diffuse reflection is possible. Initial measurements on selected clothing materials have indicated that there is sufficient transmission to allow NIR spectra from concealed chemicals to be collected. The effect of the clothing material on the observed spectra has also been quantified. The clothing materials ranged from cotton to man-made fibres. Spectra have been collected at stand-off distances of several metres or more, using a suitable lens system and an NIR spectrometer. The optics required to achieve this will be described, and some spectra from chemicals hidden behind clothing will be presented. The further steps necessary to provide correct identification of chemicals such as ammonium nitrate in granular form will also be given, involving signal analysis methods. A set of spectra will be shown that have been collected and analysed, for a wide range of clothing fabric materials, indicating that the technique could have wide application to personal screening situations.

  19. Classification of burn injuries using near-infrared spectroscopy.

    PubMed

    Sowa, Michael G; Leonardi, Lorenzo; Payette, Jeri R; Cross, Karen M; Gomez, Manuel; Fish, Joel S

    2006-01-01

    Early surgical management of those burn injuries that will not heal spontaneously is critical. The decision to excise and graft is based on a visual assessment that is often inaccurate but yet continues to be the primary means of grading the injury. Superficial and intermediate partial-thickness injuries generally heal with appropriate wound care while deep partial- and full-thickness injuries generally require surgery. This study explores the possibility of using near-infrared spectroscopy to provide an objective and accurate means of distinguishing shallow injuries from deeper burns that require surgery. Twenty burn injuries are studied in five animals, with burns covering <1% of the total body surface area. Carefully controlled superficial, intermediate, and deep partial-thickness injuries as well as full-thickness injuries could be studied with this model. Near-infrared reflectance spectroscopy was used to evaluate these injuries 1 to 3 hours after the insult. A probabilistic model employing partial least-squares logistic regression was used to determine the degree of injury, shallow (superficial or intermediate partial) from deep (deep partial and full thickness), based on the reflectance spectrum of the wound. A leave-animal-out cross-validation strategy was used to test the predictive ability of a 2-latent variable, partial least-squares logistic regression model to distinguish deep burn injuries from shallow injuries. The model displayed reasonable ranking quality as summarized by the area under the receiver operator characteristics curve, AUC = 0.879. Fixing the threshold for the class boundaries at 0.5 probability, the model sensitivity (true positive fraction) to separate deep from shallow burns was 0.90, while model specificity (true negative fraction) was 0.83. Using an acute porcine model of thermal burn injuries, the potential of near-infrared spectroscopy to distinguish between shallow healing burns and deeper burn injuries was demonstrated. While

  20. Red and near-infrared spectral reflectance of snow

    NASA Technical Reports Server (NTRS)

    Obrien, H. W.; Munis, R. H.

    1975-01-01

    The spectral reflectance of snow in the range of 0.60 to 2.50 microns wavelengths was studied in a cold laboratory using natural snow and simulated preparations of snow. A white barium sulfate powder was used as the standard for comparison. The high reflectance (usually nearly 100%) of fresh natural snow in visible wavelengths declines rapidly at wavelengths longer than the visible, as the spectral absorption coefficients of ice increase. Aging snow becomes only somewhat less reflective than fresh snow in the visible region and usually retains a reflectance greater than 80%. In the near infrared, aging snow tends to become considerably less reflective than fresh snow.

  1. Measurement of Trans-Fatty Acids in Cereal Products Without Oil Extraction Using NIR Reflectance Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infrared (NIR) reflectance spectroscopy was evaluated as a rapid technique, to determine the trans-fatty acid content of ground cereal products. NIR spectra were obtained with a dispersive spectrometer and trans-fatty acids determined by modified AOAC Method 996.01. First derivative PLS1 mode...

  2. Infrared reflectance of high altitude clouds.

    PubMed

    Hovis, W A; Blaine, L R; Forman, M L

    1970-03-01

    The spectral reflectance characteristics of cirrostratus, cirrus clouds, and a jet contrail, in the 0.68-2.4-micro spectral interval, are of interest for remote sensing of cloud types from orbiting satellites. Measurements made with a down-looking spectrometer from a high altitude aircraft show differences between the signatures of naturally formed ice clouds, a fresh jet contrail, and a snow covered surface.

  3. Capabilities and Limitations of Infrared Reflectance Microspectroscopy

    NASA Technical Reports Server (NTRS)

    Klima, R. L.; Pieters, C. M.

    2005-01-01

    Technological improvements in IR microspectroscopy have made it an increasingly appealing tool for planetary mineralogy. Microspectroscopy presents the prospect of examining small samples nondestructively and acquiring spectra that can be related to remote sensing observations. However, complications are introduced as a target beam size is reduced, and it is critical that limitations are understood. We present the results of a series of well constrained spectroscopic measurements, linking microspectroscopic data to traditionally collected reflectance spectra and petrologic information for the same rock.

  4. Infrared Spectroscopy of Carbonates and Martian Exobiology

    NASA Astrophysics Data System (ADS)

    Blanco, Armando; Delia, Marcella; Fonti, Sergio; Licchelli, Domenico; Marzo, Giuseppe A.; Orofino, Vincenzo

    Searching for traces of extinct and/or extant life on the surface of Mars is one of the major objectives for remote-sensing and in-situ exploration of the planet. In a recent paper we have studied the infrared (IR) spectral modifications induced by thermal processing on differently preserved carbonate fossils, in order to discriminate them from their abiotic counterparts. The main conclusion of the study has been that terrestrial fossils after a billion years are so altered that it becomes impossible to trace their biotic origin. Since it is reasonable to assume that the putative Martian fossils should be at least 3.5 billions years old, this would imply that our spectroscopic method could not be able to detect them, if their degradation rate were the same as that we have found in usual conditions for the terrestrial fossils. However, due to the different climate evolution of the two planets, there is the possibility of having two different degradation rates, much lower for Mars than for Earth. In this work we show that our method is quite effective for fossils collected in protective layers of clays and that IR spectroscopy, coupled with thermal processing, can be a useful tool for discriminating between abiotic and biotic (fossil) carbonate samples collected on the Martian surface especially in phyllosilicate-rich regions such as Mawrth Vallis. Further work is currently done in our laboratory on various samples collected from carbonate sediments of the Late Miocene (Messinian) Calcare di Base Formation in northern Calabria (Italy), in order to study their origin.

  5. Infrared spectroscopy of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Knacke, Roger F.

    1993-01-01

    Infrared spectroscopy provides unique insights into the chemistry and dynamics of the atmospheres of Jupiter, Saturn, and Titan. In 1991 we obtained data at J, H, K, and M and made repeated observations of Titan's albedo as the satellite orbited Saturn. The J albedo is 12% +/- 3% greater than the albedo measured in 1979; the H and K albedos are the same. There was no evidence for variations at any wavelength over the eastern half of Titan's orbit. We also obtained low resolution (R=50) spectra of Titan between 3.1 and 5.1 microns. The spectra contain evidence for CO and CH3D absorptions. Spectra of Callisto and Ganymede in the 4.5 micron spectral region are featureless and give albedos of 0.08 and 0.04 respectively. If Titan's atmosphere is transparent near 5 microns, its surface albedo there is similar to Callisto's. In 1992 and 1993 we obtained further spectroscopic data of Titan with the UKIRT CGS4 spectrometer. We discovered two unexpected and unexplained spectral features in the 3-4 micron spectrum of Titan. An apparent emission feature near the 3 micron (nu sub 3) band of methane indicated temperatures higher than known to be present in Titan's upper stratosphere and may be caused by unexpected non-LTE emission. An absorption feature near 3.47 microns may be caused by absorption in solid grains or aerosols in Titan's clouds. The feature is similar but not identical to organics in the interstellar matter and in comets.

  6. The near-infrared continuum emission of visual reflection nebulae

    NASA Technical Reports Server (NTRS)

    Sellgren, K.

    1984-01-01

    In the past, reflection nebulae have provided an astrophysical laboratory well suited for the study of the reflection properties of interstellar dust grains at visual and ultraviolet wavelengths. The present investigation is concerned with observations which were begun with the objective to extend to near-infrared wavelengths the study of grains in reflection. Observations of three classical visual reflection nebulae were conducted in the wavelength range from 1.25 to 2.2 microns, taking into account NGC 7023, 2023, and 2068. All three nebulae were found to have similar near-infrared colors, despite widely different colors of their illuminating stars. The brightness level shown by two of the nebulae at 2.2 microns was too high to be easily accounted for on the basis of reflected light. Attention is given to a wide variety of possible emission mechanisms.

  7. Fourier transform infrared spectroscopy and near infrared spectroscopy for the quantification of defects in roasted coffees.

    PubMed

    Craig, Ana Paula; Franca, Adriana S; Oliveira, Leandro S; Irudayaraj, Joseph; Ileleji, Klein

    2015-03-01

    The coffee strip-picking harvesting method, preferred in Brazil, results in high percentages of immature and overripe beans, as the fruits in a single tree branch do not reach ripeness at the same time. This practice, together with inappropriate processing and storage conditions, contribute to the production of high amounts of defective coffee beans in Brazil, which upon roasting will impart negative sensory aspects to the beverage. Therefore, the development of analytical methodologies that will enable the discrimination and quantification of defective and non-defective coffees after roasting is rather desirable. Given that infrared spectroscopy has been successfully applied to coffee analysis, the objective of this work was to evaluate and to compare the performances of Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopies for the quantification of defective beans in roasted coffees. Defective and non-defective Arabica coffee beans were manually selected, roasted, ground and sieved. Mixtures of defective and non-defective roasted and ground coffees were produced and analyzed, with % defects ranging from 0% to 30%. FTIR and NIR spectra were recorded, respectively, within a range of 3100-800 cm(-1) and 1200-2400 nm and submitted to mathematical processing. Quantitative models were developed by partial least squares regression (PLSR). Excellent predictive results were obtained indicating that defective coffees could be satisfactorily quantified. The correlation coefficients and the root mean squared errors of validation for the FTIR and NIR models developed to quantify the amount of defective roasted coffees mixed with non-defective ones were, respectively, as high as 0.891 and as low as 0.032, and as high as 0.953 and as low as 0.026. A comparison between the two techniques indicated that NIR provided more robust models. PMID:25618683

  8. Broadband infrared vibrational nano-spectroscopy using thermal blackbody radiation.

    PubMed

    O'Callahan, Brian T; Lewis, William E; Möbius, Silke; Stanley, Jared C; Muller, Eric A; Raschke, Markus B

    2015-12-14

    Infrared vibrational nano-spectroscopy based on scattering scanning near-field optical microscopy (s-SNOM) provides intrinsic chemical specificity with nanometer spatial resolution. Here we use incoherent infrared radiation from a 1400 K thermal blackbody emitter for broadband infrared (IR) nano-spectroscopy. With optimized interferometric heterodyne signal amplification we achieve few-monolayer sensitivity in phonon polariton spectroscopy and attomolar molecular vibrational spectroscopy. Near-field localization and nanoscale spatial resolution is demonstrated in imaging flakes of hexagonal boron nitride (hBN) and determination of its phonon polariton dispersion relation. The signal-to-noise ratio calculations and analysis for different samples and illumination sources provide a reference for irradiance requirements and the attainable near-field signal levels in s-SNOM in general. The use of a thermal emitter as an IR source thus opens s-SNOM for routine chemical FTIR nano-spectroscopy. PMID:26698997

  9. Far infrared Spectroscopy with FTIR Beam Line of MIRRORCLE 20

    SciTech Connect

    Miura, Nobuhiro; Moon, Ahsa; Nishikawa, Kishi; Kitagawa, Toshimichi; Hiraiwa, Nobuhiko; Yamada, Hironari

    2007-01-19

    A beam line for far infrared spectroscopy using Fourier Transform Infrared Spectrometer (FTIR) has been developed as a facility of tabletop synchrotron MIRRORCLE 20 in Ritsumeikan University and has been utilized to study liquid structure through analysis of intermolecular vibration in aqueous solutions. We report recent developments in the system and the examples of measured spectra.

  10. Near-Infrared Spectroscopy of Interstellar Dust

    NASA Astrophysics Data System (ADS)

    Boulanger, F.; Onaka, T.; Pilleri, P.; Joblin, C.

    2011-03-01

    Near infrared observations of reflection nebulae have set the historical ground for the discovery of interstellar PAHs, but since, space observations have focused on their mid-IR features, and data shortward of 5 μm have remained scarce. The Spitzer/IRAC images in the 3.6 and 4.5 μm channels do show that the near-IR emission from small dust particles is ubiquitous across the Galaxy, but provide no spectroscopic information. To investigate the nature of this near-IR dust emission, we have obtained AKARI spectroscopic observations, over the 2.5-5 μm spectral range, for a set of archetype PDRs mapped with the Spitzer spectrometer at mid-IR wavelengths. These AKARI data supplement earlier observations with the SWS ISO spectrometer, in providing the gain in sensitivity needed to observe low excitation sources, and the spatial information required to spatially correlate near-IR spectroscopic signatures with physical conditions and observed changes in mid-IR spectra. This paper presents the first results of the data analysis, in relation to two open questions on interstellar PAHs. (1) Is there an evolutionary link from aliphatic carbon dust to PAHs? (2) What is the origin of the near-IR dust continuum? The AKARI spectra display features longward of the main 3.29 μm PAH feature, and continuum emission. The intensity ratio between the features ascribed to aliphatic CH bonds and the 3.29 μm aromatic band, varies spatially in a way that may be interpreted as evidence for aromatization of the smallest dust particles by photo-processing. The continuum displays a striking step-increase across the 3.29 μm feature. We also present a spectrum of a photodissociation region with a feature at 4.65 μm, which has been speculated to be related to the CD stretch in aliphatic hydrocarbon side-groups on PAHs.

  11. Infrared reflection nebulae in Orion Molecular Cloud 2

    NASA Technical Reports Server (NTRS)

    Pendleton, Yvonne; Werner, M. W.; Capps, R.; Lester, D.

    1986-01-01

    New observations of Orion Molecular Cloud 2 have been made from 1 to 100 microns using the NASA Infrared Telescope Facility and the Kuiper Airborne Observatory. An extensive program of polarimetry, photometry, and spectrophotometry has shown that the extended emission regions associated with two of the previously known near-infrared sources, IRS 1 and IRS 4, are infrared reflection nebulae, and that the compact sources IRS 1 and IRS 4 are the main luminosity sources in the cloud. The constraints from the far-infrared observations and an analysis of the scattered light from the IRS 1 nebula show that OMC-2/IRS 1 can be characterized by L of 500 solar luminosities or less and T of roughly 1000 K. The near-infrared albedo of the grains in the IRS 1 nebula is greater than 0.08.

  12. Infrared reflection nebulae in Orion molecular cloud 2

    NASA Technical Reports Server (NTRS)

    Pendleton, Y.; Werner, M. W.; Capps, R.; Lester, D.

    1986-01-01

    New obervations of Orion Molecular Cloud-2 have been made from 1-100 microns using the NASA Infrared Telescope Facility and the Kuiper Airborne Observatory. An extensive program of polarimetry, photometry and spectrophotometry has shown that the extended emission regions associated with two of the previously known near infrared sources, IRS1 and IRS4, are infrared reflection nebulae, and that the compact sources IRS1 and IRS4 are the main luminosity sources in the cloud. The constraints from the far infrared observations and an analysis of the scattered light from the IRS1 nebula show that OMC-2/IRS1 can be characterized by L less than or equal to 500 Solar luminosities and T approx. 1000 K. The near infrared (1-5) micron albedo of the grains in the IRS1 nebula is greater than 0.08.

  13. Infrared spectra of lunar soil analogs. [spectral reflectance of minerals

    NASA Technical Reports Server (NTRS)

    Aronson, J. R.

    1977-01-01

    The infrared spectra of analogs of lunar soils were investigated to further the development of methodology for interpretation of remotely measured infrared spectra of the lunar surface. The optical constants of dunite, bytownite, augite, ilmenite, and a mare glass analog were obtained. The infrared emittance spectra of powdered minerals were measured and compared with spectra calculated by the reflectance theory using a catalog of optical constants. The results indicate that the predictions of the theory closely simulate the experimental measurements if the optical constants are properly derived.

  14. Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Edlridge, Jeffrey I.; Martin, Richard E.

    2009-01-01

    An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed yttria-stabilized zirconia coatings on turbine-engine components. Progression of TBC delamination occurs by the formation of buried cracks that grow and then link together to produce eventual TBC spallation. The mid-infrared reflectance imaging system described here makes it possible to see delamination progression that is invisible to the unaided eye, and therefore give sufficiently advanced warning before delamination progression adversely affects engine performance and safety. The apparatus (see figure) includes a commercial mid-infrared camera that contains a liquid-nitrogen-cooled focal plane indium antimonide photodetector array, and imaging is restricted by a narrow bandpass centered at wavelength of 4 microns. This narrow wavelength range centered at 4 microns was chosen because (1) it enables avoidance of interfering absorptions by atmospheric OH and CO2 at 3 and 4.25 microns, respectively; and (2) the coating material exhibits maximum transparency in this wavelength range. Delamination contrast is produced in the midinfrared reflectance images because the introduction of cracks into the TBC creates an internal TBC/air-gap interface with a high diffuse reflectivity of 0.81, resulting in substantially higher reflectance of mid-infrared radiation in regions that contain buried delamination cracks. The camera is positioned a short distance (.12 cm) from the specimen. The mid-infrared illumination is generated by a 50-watt silicon carbide source positioned to the side of the mid-infrared camera, and the illumination is collimated and reflected onto the specimen by a 6.35-cm-diameter off-axis paraboloidal mirror. Because the collected images are of a steady-state reflected intensity (in

  15. Thermal Infrared Reflective Metal Oxide Sol-Gel Coatings for Carbon Fiber Reinforced Composite Structures

    NASA Astrophysics Data System (ADS)

    Richard, Brandon Demar

    Recent trends in composite research include the development of structural materials with multiple functionalities. In new studies, novel materials are being designed, developed, modified, and implemented into composite designs. Typically, an increase in functionality requires additional material phases within one system. The presence of excessive phases can result in deterioration of individual or overall properties. True multi-functional materials must maintain all properties at or above the minimum operating limit. In this project, samples of antimony and cobalt-doped tin oxide (ATO(Co2O 3)) sol-gel solutions are used to coat carbon fibers and are heat treated at a temperature range of 200 - 500 °C. Results from this research are used to model the implementation of sol-gel coatings into carbon fiber reinforced multifunctional composite systems. This research presents a novel thermo-responsive sol-gel/ (dopant) combination and evaluation of the actuating responses (reflectivity and surface heat dissipation) due to various heat treatment temperatures. While ATO is a well-known transparent conductive material, the implementation of ATO on carbon fibers for infrared thermal reflectivity has not been examined. These coatings serve as actuators capable of reflecting thermal infrared radiation in the near infrared wavelengths of 0.7-1.2 μm. By altering the level of Co2O3 and heat treatment temperatures, optimal optical properties are obtained. While scanning electron microscopy (SEM) is used for imaging, electron diffraction spectroscopy (EDS) is used to verify the compounds present in the coatings. Fourier transform infrared (FT-IR) spectroscopy was performed to analyze the chemical bonds and reflectivity in the infrared spectra after the heat treatments. Total reflection and angle-dependent reflectivity measurements were performed on the coatings in the wavelengths of 0.7-2 μm. Laser induced damage threshold testing was done to investigate the dielectric breakdown

  16. IR Cards: Inquiry-Based Introduction to Infrared Spectroscopy

    ERIC Educational Resources Information Center

    Bennett, Jacqueline; Forster, Tabetha

    2010-01-01

    As infrared spectroscopy (IR) is frequently used in undergraduate organic chemistry courses, an inductive introduction to IR spectroscopy that uses index cards printed with spectra, structures, and chemical names is described. Groups of students are given an alphabetized deck of these "IR cards" to sort into functional groups. The students then…

  17. Near-infrared spectroscopy for burning plasma diagnostic applicationsa)

    NASA Astrophysics Data System (ADS)

    Soukhanovskii, V. A.

    2008-10-01

    Ultraviolet and visible (UV-VIS, 200-750nm) atomic spectroscopy of neutral and ionized fuel species (H, D, T, and Li) and impurities (e.g., He, Be, C, and W) is a key element of plasma control and diagnosis on International Thermonuclear Experimental Reactor and future magnetically confined burning plasma experiments (BPXs). Spectroscopic diagnostic implementation and performance issues that arise in the BPX harsh nuclear environment in the UV-VIS range, e.g., degradation of first mirror reflectivity under charge-exchange atom bombardment (erosion) and impurity deposition, permanent and dynamic loss of window, and optical fiber transmission under intense neutron and γ-ray fluxes, are either absent or not as severe in the near-infrared (NIR, 750-2000nm) range. An initial survey of NIR diagnostic applications has been undertaken on the National Spherical Torus Experiment. It is demonstrated that NIR spectroscopy can be used for machine protection and plasma control applications, as well as contribute to plasma performance evaluation and physics studies. Emission intensity estimates demonstrate that NIR measurements are possible in the BPX plasma operating parameter range. Complications in the NIR range due to the parasitic background emissions are expected to occur at very high plasma densities, low impurity densities, and at high plasma-facing component temperatures.

  18. Infrared Spectroscopy of HNO and Noh Suspended in Solid Parahydrogen

    NASA Astrophysics Data System (ADS)

    Anderson, David T.; Ruzi, Mahmut

    2013-06-01

    The only report in the literature on the infrared spectroscopy of the parent oxynitrene NOH was performed using Ar matrix isolation spectroscopy at 10 K. In this previous study, the NOH is synthesized by co-deposition of NO/Ar and a H_2/Ar mixture that is passed through a microwave discharge to create H-atoms. The H-atoms recombine with NO in the Ar matrix to produce mostly HNO, but some NOH is produced as well. In this work we irradiate NO doped parahydrogen solids at 2 K using 193 nm radiation which is known to generate H-atoms as by-products. After the photolysis laser is stopped, we detect growth of HNO and NOH presumably due to reactions of H-atoms with NO analogous to the previous Ar matrix study. The higher energy NOH isomer is predicted by high-level calculations to be in a triplet ground electronic state. Interestingly, the infrared absorptions of NOH for the two observed vibrational modes (bend and OH stretch) display fine structure; an intense central peak with smaller peaks spaced symmetrically to both lower and higher wavenumbers. Further, the spacing between the peaks is the same for both vibrational modes. We believe this fine structure reflects the zero-field splitting of the triplet ground state of NOH (magnetic dipole-dipole interaction) and our most current results and analysis will be presented. G. Maier, H. P. Reisenauer, M. De Marco, Angew. Chem. Int. Ed. 38, 108-110 (1999). M. Fushitani and T. Momose, Low Temp. Phys. 29, 740-743 (2003). U. Bozkaya, J. M. Turney, Y. Yamaguchi, and H. F. Schaefer III, J. Chem. Phys. 136, 164303 (2012).

  19. Near infrared spectroscopy of stearic acid adsorbed on montmorillonite.

    PubMed

    Lu, Longfei; Cai, Jingong; Frost, Ray L

    2010-03-01

    The adsorption of stearic acid on both sodium montmorillonites and calcium montmorillonites has been studied by near infrared spectroscopy complimented with infrared spectroscopy. Upon adsorption of stearic acid on Ca-Mt additional near infrared bands are observed at 8236 cm(-1) and is assigned to an interaction of stearic acid with the water of hydration. Upon adsorption of the stearic acid on Na-Mt, the NIR bands are now observed at 5671, 5778, 5848 and 5912 cm(-1) and are assigned to the overtone and combination bands of the CH fundamentals. Additional bands at 4177, 4250, 4324, 4337, 4689 and 4809 cm(-1) are attributed to CH combination bands resulting from the adsorption of the stearic acid. Stearic acid is used as a model molecule for adsorption studies. The application of near infrared spectroscopy to the study of this adsorption proved most useful. PMID:20071218

  20. Infrared and Near-Infrared Spectroscopy of Acetylacetone and Hexafluoroacetylacetone.

    PubMed

    Howard, Daryl L; Kjaergaard, Henrik G; Huang, Jing; Meuwly, Markus

    2015-07-23

    The infrared and near-infrared spectra of acetylacetone, acetylacetone-d8, and hexafluoroacetylacetone are characterized from experiment and computations at different levels. In the fundamental region, the intramolecular hydrogen bonded OH-stretching transition is clearly observed as a very broad band with substantial structure and located at significantly lower frequency compared to common OH-stretching frequencies. There is no clear evidence for OH-stretching overtone transitions in the near-infrared region, which is dominated by the CH-stretching overtones of the methine and methyl CH bonds. From molecular dynamics (MD) simulations, with a potential energy surface previously validated for tunneling splittings, the infrared spectra are determined and used in assigning the experimentally measured ones. It is found that the simulated spectrum in the region associated with the proton transfer mode is exquisitely sensitive to the height of the barrier for proton transfer. Comparison of the experimental and the MD simulated spectra establishes that the barrier height is around 2.5 kcal/mol, which favorably compares with 3.2 kcal/mol obtained from high-level electronic structure calculations.

  1. Extended near-infrared emission from visual reflection nebulae

    NASA Technical Reports Server (NTRS)

    Sellgren, K.; Werner, M. W.; Dinerstein, H. L.

    1983-01-01

    Extended near infrared (2 to 5 microns) emission was observed from three visual reflection nebulae, NGC 7023, 2023, and 2068. The emission from each nebula consists of a smooth continuum, which can be described by a greybody with a color temperature of 1000 K, and emission features at 3.3 and 3.4 microns. The continuum emission cannot be explained by free-free emission, reflected light, or field stars, or by thermal emission from grains, with commonly accepted ratios of infrared to ultraviolet emissivities, which are in equilibrium with the stellar radiation field. A possible explanation is thermal emission from grains with extremely low ratios of infrared to ultraviolet emissivities, or from grains with a temperature determined by mechanisms other than equilibrium radiative heating. Another possibility is continuum fluorescence. Previously announced in STAR N83-25629

  2. Extended near infrared emission from visual reflection nebulae

    NASA Technical Reports Server (NTRS)

    Sellgren, K.; Werner, M. W.; Dinerstein, H. L.

    1982-01-01

    Extended near infrared (2 to 5 microns) emission was observed from three visual reflection nebulae, NGC 7023, 2023, and 2068. The emission from each nebula consists of a smooth continuum, which can be described by a greybody with a color temperature of 1000 K, and emission features at 3.3 and 3.4 microns. The continuum emission cannot be explained by free-free emission, reflected light, or field stars, or by thermal emission from grains, with commonly accepted ratios of infrared to ultraviolet emissivities, which are in equilibrium with the stellar radiation field. A possible explanation is thermal emission from grains with extremely low ratios of infrared to ultraviolet emissivities, or from grains with a temperature determined by mechanisms other than equilibrium radiative heating. Another possibility is continuum fluorescence.

  3. Improved Spatial Resolution For Reflection Mode Infrared Spectromicroscopy

    SciTech Connect

    Bechtel, Hans A; Martin, Michael C.; May, T. E.; Lerch, Philippe

    2009-08-13

    Standard commercial infrared microscopes operating in reflection mode use a mirror to direct the reflected light from the sample to the detector. This mirror blocks about half of the incident light, however, and thus degrades the spatial resolution by reducing the numerical aperture of the objective. Here, we replace the mirror with a 50% beamsplitter to allow full illumination of the objective and retain a way to direct the reflected light to the detector. The improved spatial resolution is demonstrated using a microscope coupled to a synchrotron source.

  4. Fresh Soil Sensing using Visible and Near Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Maleki, M. R.

    2009-04-01

    Fast, precise and affordable soil analytical techniques are needed for the determination of soil fertility of each zone of a field in site specific land management. The objective of this poster is to demonstrate how nutrients can be estimated from fresh soil using visible (VIS) and near infrared (NIR) spectroscopy method. This could be carried out by summarizing the methodology to develop a calibration model for soil phosphorus with the VIS-NIR spectroscopy method. Obviously, it can be simply extended for other nutrients with the same methodology. A large samples set should be collected from different fields with a wide range of soil type and texture. The samples in this set should be represented a wide range of moisture content and soil nutrient which is desired to be calibrated by the spectroscopy technique. Immediately after sampling, the samples should be kept in a cold room (± 1 °C) until the time of the spectral measurement and the chemical analysis. The samples should be taken from the cold room one hour before the spectral measurement to ensure that the samples were at room temperature and no condensation occurs on the optical instruments. Each soil sample was thoroughly mixed and debris such as plant material and stones were removed. The soil sample was divided into three parts, one part for spectral measurement, another part for chemical analysis and the rest was archived. The part for chemical analysis should be examined for their soil nutrients. A small amount of soil (about 30 g) should be placed in a small plastic petridish (e.g. 7.5 mm depth and 30 mm diameter). The soil in the petridish should be first pressed and then carefully levelled in order to obtain a smooth surface for a maximum light reflectance. Soil samples should be put under the spectrophotometer. Three reflectance spectra should be measured on each soil specimen by rotating the plastic cups over 120°. Having finished measuring, the reflectance data should be put against the chemical

  5. [Tri-Level Infrared Spectroscopic Identification of Hot Melting Reflective Road Marking Paint].

    PubMed

    Li, Hao; Ma, Fang; Sun, Su-qin

    2015-12-01

    In order to detect the road marking paint from the trace evidence in traffic accident scene, and to differentiate their brands, we use Tri-level infrared spectroscopic identification, which employs the Fourier transform infrared spectroscopy (FTIR), the second derivative infrared spectroscopy(SD-IR), two-dimensional correlation infrared spectroscopy(2D-IR) to identify three different domestic brands of hot melting reflective road marking paints and their raw materials in formula we Selected. The experimental results show that three labels coatings in ATR and FTIR spectrograms are very similar in shape, only have different absorption peak wave numbers, they have wide and strong absorption peaks near 1435 cm⁻¹, and strong absorption peak near 879, 2955, 2919, 2870 cm⁻¹. After enlarging the partial areas of spectrograms and comparing them with each kind of raw material of formula spectrograms, we can distinguish them. In the region 700-970 and 1370-1 660 cm⁻¹ the spectrograms mainly reflect the different relative content of heavy calcium carbonate of three brands of the paints, and that of polyethylene wax (PE wax), ethylene vinyl acetate resin (EVA), dioctyl phthalate (DOP) in the region 2800-2960 cm⁻¹. The SD-IR not only verify the result of the FTIR analysis, but also further expand the microcosmic differences and reflect the different relative content of quartz sand in the 512-799 cm-1 region. Within the scope of the 1351 to 1525 cm⁻¹, 2D-IR have more significant differences in positions and numbers of automatically peaks. Therefore, the Tri-level infrared spectroscopic identification is a fast and effective method to distinguish the hot melting road marking paints with a gradually improvement in apparent resolution.

  6. [Tri-Level Infrared Spectroscopic Identification of Hot Melting Reflective Road Marking Paint].

    PubMed

    Li, Hao; Ma, Fang; Sun, Su-qin

    2015-12-01

    In order to detect the road marking paint from the trace evidence in traffic accident scene, and to differentiate their brands, we use Tri-level infrared spectroscopic identification, which employs the Fourier transform infrared spectroscopy (FTIR), the second derivative infrared spectroscopy(SD-IR), two-dimensional correlation infrared spectroscopy(2D-IR) to identify three different domestic brands of hot melting reflective road marking paints and their raw materials in formula we Selected. The experimental results show that three labels coatings in ATR and FTIR spectrograms are very similar in shape, only have different absorption peak wave numbers, they have wide and strong absorption peaks near 1435 cm⁻¹, and strong absorption peak near 879, 2955, 2919, 2870 cm⁻¹. After enlarging the partial areas of spectrograms and comparing them with each kind of raw material of formula spectrograms, we can distinguish them. In the region 700-970 and 1370-1 660 cm⁻¹ the spectrograms mainly reflect the different relative content of heavy calcium carbonate of three brands of the paints, and that of polyethylene wax (PE wax), ethylene vinyl acetate resin (EVA), dioctyl phthalate (DOP) in the region 2800-2960 cm⁻¹. The SD-IR not only verify the result of the FTIR analysis, but also further expand the microcosmic differences and reflect the different relative content of quartz sand in the 512-799 cm-1 region. Within the scope of the 1351 to 1525 cm⁻¹, 2D-IR have more significant differences in positions and numbers of automatically peaks. Therefore, the Tri-level infrared spectroscopic identification is a fast and effective method to distinguish the hot melting road marking paints with a gradually improvement in apparent resolution. PMID:26964206

  7. Studies of dust grain properties in infrared reflection nebulae.

    PubMed

    Pendleton, Y J; Tielens, A G; Werner, M W

    1990-01-20

    We have developed a model for reflection nebulae around luminous infrared sources embedded in dense dust clouds. The aim of this study is to determine the sizes of the scattering grains. In our analysis, we have adopted an MRN-like power-law size distribution (Mathis, Rumpl, and Nordsieck) of graphite and silicate grains, but other current dust models would give results which were substantially the same. In the optically thin limit, the intensity of the scattered light is proportional to the dust column density, while in the optically thick limit, it reflects the grain albedo. The results show that the shape of the infrared spectrum is the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of our model results with infrared observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse interstellar medium, or one consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains (approximately 5000 angstroms). By adding water ice mantles to the silicate and graphite cores, we have modeled the 3.08 micrometers ice band feature, which has been observed in the spectra of several infrared reflection nebulae. We show that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. We show that the shape of the ice band is diagnostic of the presence of large grains, as previously suggested by Knacke and McCorkle. Comparison with observations of the BN/KL reflection nebula in the OMC-1 cloud shows that large ice grains (approximately 5000 angstroms) contribute substantially to the scattered light. PMID:11538693

  8. Studies of dust grain properties in infrared reflection nebulae.

    PubMed

    Pendleton, Y J; Tielens, A G; Werner, M W

    1990-01-20

    We have developed a model for reflection nebulae around luminous infrared sources embedded in dense dust clouds. The aim of this study is to determine the sizes of the scattering grains. In our analysis, we have adopted an MRN-like power-law size distribution (Mathis, Rumpl, and Nordsieck) of graphite and silicate grains, but other current dust models would give results which were substantially the same. In the optically thin limit, the intensity of the scattered light is proportional to the dust column density, while in the optically thick limit, it reflects the grain albedo. The results show that the shape of the infrared spectrum is the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of our model results with infrared observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse interstellar medium, or one consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains (approximately 5000 angstroms). By adding water ice mantles to the silicate and graphite cores, we have modeled the 3.08 micrometers ice band feature, which has been observed in the spectra of several infrared reflection nebulae. We show that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. We show that the shape of the ice band is diagnostic of the presence of large grains, as previously suggested by Knacke and McCorkle. Comparison with observations of the BN/KL reflection nebula in the OMC-1 cloud shows that large ice grains (approximately 5000 angstroms) contribute substantially to the scattered light.

  9. Cancer diagnosis by infrared spectroscopy: methodological aspects

    NASA Astrophysics Data System (ADS)

    Jackson, Michael; Kim, Keith; Tetteh, John; Mansfield, James R.; Dolenko, Brion; Somorjai, Raymond L.; Orr, F. W.; Watson, Peter H.; Mantsch, Henry H.

    1998-04-01

    IR spectroscopy is proving to be a powerful tool for the study and diagnosis of cancer. The application of IR spectroscopy to the analysis of cultured tumor cells and grading of breast cancer sections is outlined. Potential sources of error in spectral interpretation due to variations in sample histology and artifacts associated with sample storage and preparation are discussed. The application of statistical techniques to assess differences between spectra and to non-subjectively classify spectra is demonstrated.

  10. Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

    SciTech Connect

    Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

    2015-05-22

    While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packed as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

  11. Infrared reflectance spectra: effects of particle size, provenance and preparation

    NASA Astrophysics Data System (ADS)

    Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.; Blake, Thomas A.; Forland, Brenda M.; Szecsody, J. E.; Johnson, Timothy J.

    2014-10-01

    We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectance spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 - 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.

  12. Infrared reflectance spectra: Effects of particle size, provenance and preparation

    SciTech Connect

    Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.; Blake, Thomas A.; Forland, Brenda M.; Szecsody, James E.; Johnson, Timothy J.

    2014-09-22

    We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectance spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.

  13. Improved source of infrared radiation for spectroscopy

    NASA Technical Reports Server (NTRS)

    Burkhard, D. G.; Rao, K. N.

    1971-01-01

    Radiation from a crimped V-groove in the electrically heated metallic element of a high-resolution infrared spectrometer is more intense than that from plane areas adjacent to the element. Radiation from the vee and the flat was compared by alternately focusing on the entrance slit of a spectrograph.

  14. Terahertz and infrared spectroscopy of gated large-area graphene.

    PubMed

    Ren, Lei; Zhang, Qi; Yao, Jun; Sun, Zhengzong; Kaneko, Ryosuke; Yan, Zheng; Nanot, Sébastien; Jin, Zhong; Kawayama, Iwao; Tonouchi, Masayoshi; Tour, James M; Kono, Junichiro

    2012-07-11

    We have fabricated a centimeter-size single-layer graphene device with a gate electrode, which can modulate the transmission of terahertz and infrared waves. Using time-domain terahertz spectroscopy and Fourier-transform infrared spectroscopy in a wide frequency range (10-10 000 cm(-1)), we measured the dynamic conductivity change induced by electrical gating and thermal annealing. Both methods were able to effectively tune the Fermi energy, E(F), which in turn modified the Drude-like intraband absorption in the terahertz as well as the "2E(F) onset" for interband absorption in the mid-infrared. These results not only provide fundamental insight into the electromagnetic response of Dirac fermions in graphene but also demonstrate the key functionalities of large-area graphene devices that are desired for components in terahertz and infrared optoelectronics. PMID:22663563

  15. Characterization of waste rock associated with acid drainage at the Penn Mine, California, by ground-based visible to short-wave infrared reflectance spectroscopy assisted by digital mapping

    USGS Publications Warehouse

    Montero, S.I.C.; Brimhall, G.H.; Alpers, C.N.; Swayze, G.A.

    2005-01-01

    Prior to remediation at the abandoned Cu-Zn Penn Mine in the Foothills massive sulfide belt of the Sierra Nevada, CA, acid mine drainage (AMD) was created, in part, by the subaerial oxidation of sulfides exposed on several waste piles. To support remediation efforts, a mineralogical study of the waste piles was undertaken by acquiring reflectance spectra (measured in the visible to short-wave infrared range of light (0.35-2.5 ??m) using a portable, digitally integrated pen tablet PC mapping system with differential global positioning system and laser rangefinder support. Analysis of the spectral data made use of a continuum removal and band-shape comparison method, and of reference spectral libraries of end-member minerals and mineral mixtures. Identification of secondary Fe-bearing minerals focused on band matching in the region between 0.43 and 1.3 ??m. Identification of sheet and other silicates was based on band-shape analysis in the region between 1.9 and 2.4 ??m. Analysis of reflectance spectra of characterized rock samples from the mine helped in gauging the spectral response to particle size and mixtures. The resulting mineral maps delineated a pattern of accumulation of secondary Fe minerals, wherein centers of copiapite and jarosite that formed at low pH (<3) were surrounded successively by goethite and hematite, which mark progressive increases in pH. This pattern represents the evolution of acid solutions discharged from the pyritic waste piles and the subsequent accumulation of secondary precipitates by hydrolysis reactions. The results highlight the high capacity of the pyritic waste to release further acid mine drainage into the environment, as well as the effectiveness of the mapping method to detect subtle changes in surface mineralogy and to produce maps useful to agencies responsible for remediating the site. ?? 2004 Elsevier B.V. All rights reserved.

  16. Studies of Planetary Materials Using Cryogenic Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dalton, J. B.; Roush, T. L.; Jamieson, C. S.

    2002-09-01

    Current and planned spacecraft missions to Mars and the Outer Solar System rely on laboratory measurements to facilitate interpretation of remote-sensing data. Solar system objects typically occupy environments far from terrestrial ambient conditions. Compositional studies based on infrared spectroscopy are particularly dependent on laboratory work, as many planetary materials exhibit changes in spectral behavior due to extremes of temperature, pressure, and other influences. The conditions at the surfaces of icy satellites, for example, are difficult to reproduce except under tightly controlled specifications. This is illustrated by comparing the visible and near-infrared reflectance of several materials measured at cryogenic temperatures. Water ice, which is of interest for most solid bodies of the outer solar system, exhibits strong temperature dependence, as does methane ice (Grundy and Schmitt, 1998; Grundy et al., 2002). Hydrated materials, such as salts anticipated to be abundant at Europa, and ammonia hydrates relevant to the Saturnian satellites, also display strong variations with temperature (Dalton and Clark, 1998; McCord et al., 1999; Dalton, 2001). Pyroxenes and olivines, found in rocky bodies including the moon, meteorites, and Mars, also change with temperature (Singer and Roush, 1985; Moroz et al., 2000; Hinrichs and Lucey, 2002). We have initiated a program investigating temperature sensitivity of planetary materials in support of spacecraft missions. Measurements are performed in a cryogenic vacuum environment chamber with a compressed helium cryostat capable of maintaining temperatures as low as 10 Kelvin. We will report on materials such as sulfate hydrates, which display profound spectral changes at low temperatures, and other materials we have measured, such as calcium carbonate, iron sulfide, and tholins (Roush and Dalton, 2002). While many materials are expected to show only modest variations, careful measurement and analysis of planetary

  17. The Influence of Particle Size on Infrared Reflectance Spectra

    SciTech Connect

    Myers, Tanya L.; Brauer, Carolyn S.; Su, Yin-Fong; Blake, Thomas A.; Johnson, Timothy J.; Richardson, Robert L.

    2014-06-13

    Reflectance spectra of solids are influenced by the absorption coefficient as well as the particle size and morphology. In the infrared, spectral features may be observed as either maxima or minima: in general, the upward-going peaks in the reflectance spectrum result from surface scattering, which are rays that have reflected from the surface without penetration, whereas downward-going peaks result from either absorption or volume scattering, i.e. rays that have penetrated into the sample or refracted into the sample interior and are not reflected. The light signal reflected from solids usually encompasses all these effects which include dependencies on particle size, morphology and sample density. This paper measures the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to understand the effects on the spectral features as a function of the mean grain size of the sample. The bulk materials were ground with a mortar and pestle and then sieved to separate the samples into various size fractions: 0-45, 45-90, 90-180, 180-250, 250-500, and >500 microns. The directional-hemispherical spectra were recorded using a Fourier transform infrared spectrometer equipped with an integrating sphere to measure the reflectance for all of the particle-size fractions. We have studied both organic and inorganic materials, but this paper focuses on inorganic salts, NaNO3 in particular. Our studies clearly show that particle size has an enormous influence on the measured reflectance spectra for bulk materials and that successful identification requires sufficient representative reflectance data so as to include the particle size(s) of interest. Origins of the effects are discussed.

  18. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect

    Curl, R.F.; Glass, G.P.

    1993-12-01

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  19. On-line fermentation monitoring by mid-infrared spectroscopy.

    PubMed

    Mazarevica, Gunta; Diewok, Josef; Baena, Josefa R; Rosenberg, Erwin; Lendl, Bernhard

    2004-07-01

    A new method for on-line monitoring of fermentations using mid-infrared (MIR) spectroscopy has been developed. The method has been used to predict the concentrations of glucose and ethanol during a baker's yeast fermentations. A completely automated flow system was employed as an interface between the bioprocess under study and the Fourier transform infrared (FT-IR) spectrometer, which was equipped with a flow cell housing a diamond attenuated total reflection (ATR) element. By using the automated flow system, experimental problems related to adherence of CO(2) bubbles to the ATR surface, as well as formation of biofilms on the ATR surface, could be efficiently eliminated. Gas bubbles were removed during sampling, and by using rinsing steps any biofilm could be removed from the ATR surface. In this way, constant measuring conditions could be guaranteed throughout prolonged fermentation times (approximately 8 h). As a reference method, high-performance liquid chromatography (HPLC) with refractive index detection was used. The recorded data from different fermentations were modeled by partial least-squares (PLS) regression comparing two different strategies for the calibration. On the one hand, calibration sets were constructed from spectra recorded from either synthetic standards or from samples drawn during fermentation. On the other hand, spectra from fermentation samples and synthetic standards were combined to form a calibration set. Differences in the kinetics of the studied fermentation processes used for calibration and prediction, as well as the precision of the HPLC reference method, were identified as the main chemometric sources of error. The optimal PLS regression method was obtained using the mixed calibration set of samples from fermentations and synthetic standards. The root mean square errors of prediction in this case were 0.267 and 0.336 g/L for glucose and ethanol concentration, respectively.

  20. Advances in Mid-Infrared Spectroscopy for Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Haas, Julian; Mizaikoff, Boris

    2016-06-01

    Infrared spectroscopy in the 3–20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

  1. Advances in Mid-Infrared Spectroscopy for Chemical Analysis.

    PubMed

    Haas, Julian; Mizaikoff, Boris

    2016-06-12

    Infrared spectroscopy in the 3-20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

  2. Advances in Mid-Infrared Spectroscopy for Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Haas, Julian; Mizaikoff, Boris

    2016-06-01

    Infrared spectroscopy in the 3-20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

  3. Fourier transform infrared spectroscopy (FTIR) of laser-irradiated cementum

    NASA Astrophysics Data System (ADS)

    Rechmann, Peter; White, Joel M.; Cecchini, Silvia C. M.; Hennig, Thomas

    2003-06-01

    Utilizing Fourier Transform Infrared Spectroscopy (FTIR) in specular reflectance mode chemical changes of root cement surfaces due to laser radiation were investigated. A total of 18 samples of root cement were analyzed, six served as controls. In this study laser energies were set to those known for removal of calculus or for disinfection of periodontal pockets. Major changes in organic as well as inorganic components of the cementum were observed following Nd:YAG laser irradiation (wavelength 1064 nm, pulse duration 250 μs, free running, pulse repetition rate 20 Hz, fiber diameter 320 μm, contact mode; Iskra Twinlight, Fontona, Slovenia). Er:YAG laser irradiation (wavelength 2.94 μm, pulse duration 250 μs, free running, pulse repetition rate 6 Hz, focus diameter 620 μm, air water cooling 30 ml/min; Iskra Twinlight, Fontona, Slovenia) significantly reduced the Amid bands due to changes in the organic components. After irradiation with a frequency doubled Alexandrite laser (wavelength 377 nm, pulse duration 200 ns, q-switched, pulse repetition rate 20 Hz, beam diameter 800 μm, contact mode, water cooling 30 ml/min; laboratory prototype) only minimal reductions in the peak intensity of the Amide-II band were detected.

  4. Near-infrared imaging spectroscopy for counterfeit drug detection

    NASA Astrophysics Data System (ADS)

    Arnold, Thomas; De Biasio, Martin; Leitner, Raimund

    2011-06-01

    Pharmaceutical counterfeiting is a significant issue in the healthcare community as well as for the pharmaceutical industry worldwide. The use of counterfeit medicines can result in treatment failure or even death. A rapid screening technique such as near infrared (NIR) spectroscopy could aid in the search for and identification of counterfeit drugs. This work presents a comparison of two laboratory NIR imaging systems and the chemometric analysis of the acquired spectroscopic image data. The first imaging system utilizes a NIR liquid crystal tuneable filter and is designed for the investigation of stationary objects. The second imaging system utilizes a NIR imaging spectrograph and is designed for the fast analysis of moving objects on a conveyor belt. Several drugs in form of tablets and capsules were analyzed. Spectral unmixing techniques were applied to the mixed reflectance spectra to identify constituent parts of the investigated drugs. The results show that NIR spectroscopic imaging can be used for contact-less detection and identification of a variety of counterfeit drugs.

  5. Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Cromwell, B. K.; Shepherd, S. D.; Pender, C. W.; Wood, B. E.

    1993-01-01

    Infrared hemispherical reflectance measurements that were made on 58 chromic acid anodized tray clamps from LDEF are described. The measurements were made using a hemiellipsoidal mirror reflectometer with interferometer for wavelengths between 2-15 microns. The tray clamps investigated were from locations about the entire spacecraft and provided the opportunity for comparing the effects of atomic oxygen at each location. Results indicate there was essentially no dependence on atomic oxygen fluence for the surfaces studied, but there did appear to be a slight dependence on solar radiation exposure. The reflectances of the front sides of the tray clamps consistently were slightly higher than for the protected rear tray clamp surfaces.

  6. Quantitative analysis of peanut oil content in ternary blended edible oil using near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Huacai; Liu, Fuli; Wang, Zhilan; Jin, Shangzhong

    2008-03-01

    Calibration models of quantitative analysis of peanut oil content in ternary blended edible oil by near infrared spectroscopy were built using partial least square (PLS) regression. A total of 92 samples blended with three kinds of pure oil in different proportion (V/V) were prepared. Near infrared diffuse reflectance spectra of the samples were collected over 4 000 cm -1-10 000 cm -1 spectral region with a FT-NIR spectrometer. A calibration model of prediction to the peanut oil content was established with PLS using the original spectra and validated with leave-one-out cross validation method. The correlation coefficient and the RMSEC of the model were 0.9926 and 2.91%, respectively. The result showed that near infrared spectroscopy could be an ideal tool for fast determination to the peanut oil content in blended edible oil.

  7. Infrared microcalorimetric spectroscopy using quantum cascade lasers.

    PubMed

    Morales-Rodríguez, M E; Senesac, L R; Rajic, S; Lavrik, N V; Smith, D B; Datskos, P G

    2013-02-15

    We have investigated an IR microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the IR photothermal spectra of molecules adsorbed on the surface of uncooled thermal micromechanical detectors. Although we use a chemical layer to absorb target molecules, IR microcalorimetric spectroscopy requires no chemical specific coatings. The chemical specificity of the presented method is a consequence of the wavelength-specific absorption of IR photons from tunable quantum cascade lasers due to vibrational spectral bands of the analyte. We have obtained IR photothermal spectra for trace concentrations of 1,3,5-Trinitroperhydro-1,3,5-triazine and a monolayer of 2-Sulfanylethan-1-ol (2-mercaptoethanol) over the wavelength region from 6 to 10 μm. We found that both chemicals exhibit a number of photothermal absorption features that are in good agreement with their respective IR spectra.

  8. Near-infrared spectroscopy of dark asteroids.

    PubMed

    Barucci, M A; Lazzarin, M; Owen, T; Barbieri, C; Fulchignoni, M

    1994-08-01

    Near-infrared (J, H and K bands) spectra of nine dark asteroids (chosen among a sample of supposed primitive objects between C and D classes) have been obtained at the Mauna Kea Observatory (Hawaii) with the 2.2-m telescope using KSPEC as spectrograph. The aim of this work was to search for evidence of the presence of organic materials in these objects as found in other planetary bodies as 5145 Pholus, and in some cometary nuclei. A careful analysis of the data has revealed flat or slightly redder spectra than the solar one for all observed asteroids. No evidence of distinct absorption features was found. PMID:11539179

  9. Near-infrared spectroscopy of dark asteroids.

    PubMed

    Barucci, M A; Lazzarin, M; Owen, T; Barbieri, C; Fulchignoni, M

    1994-08-01

    Near-infrared (J, H and K bands) spectra of nine dark asteroids (chosen among a sample of supposed primitive objects between C and D classes) have been obtained at the Mauna Kea Observatory (Hawaii) with the 2.2-m telescope using KSPEC as spectrograph. The aim of this work was to search for evidence of the presence of organic materials in these objects as found in other planetary bodies as 5145 Pholus, and in some cometary nuclei. A careful analysis of the data has revealed flat or slightly redder spectra than the solar one for all observed asteroids. No evidence of distinct absorption features was found.

  10. Galileo infrared imaging spectroscopy measurements at venus

    USGS Publications Warehouse

    Carlson, R.W.; Baines, K.H.; Encrenaz, Th.; Taylor, F.W.; Drossart, P.; Kamp, L.W.; Pollack, James B.; Lellouch, E.; Collard, A.D.; Calcutt, S.B.; Grinspoon, D.; Weissman, P.R.; Smythe, W.D.; Ocampo, A.C.; Danielson, G.E.; Fanale, F.P.; Johnson, T.V.; Kieffer, H.H.; Matson, D.L.; McCord, T.B.; Soderblom, L.A.

    1991-01-01

    During the 1990 Galileo Venus flyby, the Near Infrared Mapping Spectrometer investigated the night-side atmosphere of Venus in the spectral range 0.7 to 5.2 micrometers. Multispectral images at high spatial resolution indicate substantial cloud opacity variations in the lower cloud levels, centered at 50 kilometers altitude. Zonal and meridional winds were derived for this level and are consistent with motion of the upper branch of a Hadley cell. Northern and southern hemisphere clouds appear to be markedly different. Spectral profiles were used to derive lower atmosphere abundances of water vapor and other species.

  11. Direct determination of sorbitol and sodium glutamate by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) in the thermostabilizer employed in the production of yellow-fever vaccine.

    PubMed

    de Castro, Eduardo da S G; Cassella, Ricardo J

    2016-05-15

    Reference methods for quality control of vaccines usually require treatment of the samples before analysis. These procedures are expensive, time-consuming, unhealthy and require careful manipulation of the sample, making them a potential source of analytical errors. This work proposes a novel method for the quality control of thermostabilizer samples of the yellow fever vaccine employing attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR). The main advantage of the proposed method is the possibility of direct determination of the analytes (sodium glutamate and sorbitol) without any pretreatment of the samples. Operational parameters of the FTIR technique, such as the number of accumulated scans and nominal resolution, were evaluated. The best conditions for sodium glutamate were achieved when 64 scans were accumulated using a nominal resolution of 4 cm(-1). The measurements for sodium glutamate were performed at 1347 cm(-1) (baseline correction between 1322 and 1369 cm(-1)). In the case of sorbitol, the measurements were done at 890cm(-1) (baseline correction between 825 and 910 cm(-1)) using a nominal resolution of 2 cm(-1) with 32 accumulated scans. In both cases, the quantitative variable was the band height. Recovery tests were performed in order to evaluate the accuracy of the method and recovery percentages in the range 93-106% were obtained. Also, the methods were compared with reference methods and no statistical differences were observed. The limits of detection and quantification for sodium glutamate were 0.20 and 0.62% (m/v), respectively, whereas for sorbitol they were 1 and 3.3% (m/v), respectively. PMID:26992492

  12. Direct determination of sorbitol and sodium glutamate by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) in the thermostabilizer employed in the production of yellow-fever vaccine.

    PubMed

    de Castro, Eduardo da S G; Cassella, Ricardo J

    2016-05-15

    Reference methods for quality control of vaccines usually require treatment of the samples before analysis. These procedures are expensive, time-consuming, unhealthy and require careful manipulation of the sample, making them a potential source of analytical errors. This work proposes a novel method for the quality control of thermostabilizer samples of the yellow fever vaccine employing attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR). The main advantage of the proposed method is the possibility of direct determination of the analytes (sodium glutamate and sorbitol) without any pretreatment of the samples. Operational parameters of the FTIR technique, such as the number of accumulated scans and nominal resolution, were evaluated. The best conditions for sodium glutamate were achieved when 64 scans were accumulated using a nominal resolution of 4 cm(-1). The measurements for sodium glutamate were performed at 1347 cm(-1) (baseline correction between 1322 and 1369 cm(-1)). In the case of sorbitol, the measurements were done at 890cm(-1) (baseline correction between 825 and 910 cm(-1)) using a nominal resolution of 2 cm(-1) with 32 accumulated scans. In both cases, the quantitative variable was the band height. Recovery tests were performed in order to evaluate the accuracy of the method and recovery percentages in the range 93-106% were obtained. Also, the methods were compared with reference methods and no statistical differences were observed. The limits of detection and quantification for sodium glutamate were 0.20 and 0.62% (m/v), respectively, whereas for sorbitol they were 1 and 3.3% (m/v), respectively.

  13. Social Perception in Infancy: A Near Infrared Spectroscopy Study

    ERIC Educational Resources Information Center

    Lloyd-Fox, Sarah; Blasi, Anna; Volein, Agnes; Everdell, Nick; Elwell, Claire E.; Johnson, Mark H.

    2009-01-01

    The capacity to engage and communicate in a social world is one of the defining characteristics of the human species. While the network of regions that compose the social brain have been the subject of extensive research in adults, there are limited techniques available for monitoring young infants. This study used near infrared spectroscopy to…

  14. WW Domain Folding Complexity Revealed by Infrared Spectroscopy

    PubMed Central

    2015-01-01

    Although the intrinsic tryptophan fluorescence of proteins offers a convenient probe of protein folding, interpretation of the fluorescence spectrum is often difficult because it is sensitive to both global and local changes. Infrared (IR) spectroscopy offers a complementary measure of structural changes involved in protein folding, because it probes changes in the secondary structure of the protein backbone. Here we demonstrate the advantages of using multiple probes, infrared and fluorescence spectroscopy, to study the folding of the FBP28 WW domain. Laser-induced temperature jumps coupled with fluorescence or infrared spectroscopy have been used to probe changes in the peptide backbone on the submillisecond time scale. The relaxation dynamics of the β-sheets and β-turn were measured independently by probing the corresponding IR bands assigned in the amide I region. Using these wavelength-dependent measurements, we observe three kinetics phases, with the fastest process corresponding to the relaxation kinetics of the turns. In contrast, fluorescence measurements of the wild-type WW domain and tryptophan mutants exhibit single-exponential kinetics with a lifetime that corresponds to the slowest phase observed by infrared spectroscopy. Mutant sequences provide evidence of an intermediate dry molten globule state. The slowest step in the folding of this WW domain is the tight packing of the side chains in the transition from the dry molten globule intermediate to the native structure. This study demonstrates that using multiple complementary probes enhances the interpretation of protein folding dynamics. PMID:25121968

  15. Predicting cotton stelometer fiber strength by fourier transform infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The strength of cotton fibers is one of several important end-use characteristics. In routine programs, it has been mostly assessed by automation-oriented high volume instrument (HVI) system. An alternative method for cotton strength is near infrared (NIR) spectroscopy. Although previous NIR models ...

  16. Detecting Counterfeit Antimalarial Tablets by Near-Infrared Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Counterfeit antimalarial drugs are found in many developing countries, but it is challenging to differentiate between genuine and fakes due to their increasing sophistication. Near-infrared spectroscopy (NIRS) is a powerful tool in pharmaceutical forensics, and we tested this technique for discrim...

  17. Progress in far-infrared spectroscopy: Approximately 1890 to 1970

    NASA Astrophysics Data System (ADS)

    Mitsuishi, Akiyoshi

    2014-03-01

    The history of far-infrared spectroscopy from its beginning to around 1970 is reviewed. Before World War II, the size of the community investigating this topic was limited. During this period, in particular before 1925, about 90% of the papers were published by H. Rubens and his co-workers in Germany. One or two researchers from the US joined the Rubens group per year from 1890 to the beginning of 1910. During the next year or two, some researchers joined M. Czerny, who is seen as the successor of Rubens. After World War II, far-infrared techniques progressed further in the US, which did not suffer damage during the war. The advanced techniques of far-infrared grating spectroscopy were transferred from the US (R. A. Oetjen) to Japan (H. Yoshinaga). Yoshinaga and his co-workers expanded the techniques by themselves. This paper describes the historical development of far-infrared spectroscopy before Fourier transform spectroscopy became popular around 1970.

  18. WW domain folding complexity revealed by infrared spectroscopy.

    PubMed

    Davis, Caitlin M; Dyer, R Brian

    2014-09-01

    Although the intrinsic tryptophan fluorescence of proteins offers a convenient probe of protein folding, interpretation of the fluorescence spectrum is often difficult because it is sensitive to both global and local changes. Infrared (IR) spectroscopy offers a complementary measure of structural changes involved in protein folding, because it probes changes in the secondary structure of the protein backbone. Here we demonstrate the advantages of using multiple probes, infrared and fluorescence spectroscopy, to study the folding of the FBP28 WW domain. Laser-induced temperature jumps coupled with fluorescence or infrared spectroscopy have been used to probe changes in the peptide backbone on the submillisecond time scale. The relaxation dynamics of the β-sheets and β-turn were measured independently by probing the corresponding IR bands assigned in the amide I region. Using these wavelength-dependent measurements, we observe three kinetics phases, with the fastest process corresponding to the relaxation kinetics of the turns. In contrast, fluorescence measurements of the wild-type WW domain and tryptophan mutants exhibit single-exponential kinetics with a lifetime that corresponds to the slowest phase observed by infrared spectroscopy. Mutant sequences provide evidence of an intermediate dry molten globule state. The slowest step in the folding of this WW domain is the tight packing of the side chains in the transition from the dry molten globule intermediate to the native structure. This study demonstrates that using multiple complementary probes enhances the interpretation of protein folding dynamics. PMID:25121968

  19. Reflectance spectroscopy for evaluating hair follicle cycle

    NASA Astrophysics Data System (ADS)

    Liu, Caihua; Guan, Yue; Wang, Jianru; Zhu, Dan

    2014-02-01

    Hair follicle, as a mini-organ with perpetually cycling of telogen, anagen and catagen, provides a valuable experimental model for studying hair and organ regeneration. The transition of hair follicle from telogen to anagen is a significant sign for successful regeneration. So far discrimination of the hair follicle stage is mostly based on canonical histological examination and empirical speculation based on skin color. Hardly a method has been proposed to quantitatively evaluate the hair follicle stage. In this work, a commercial optical fiber spectrometer was applied to monitor diffuse reflectance of mouse skin with hair follicle cycling, and then the change of reflectance was obtained. Histological examination was used to verify the hair follicle stage. In comparison with the histological examination, the skin diffuse reflectance was relatively high for mouse with telogen hair follicles; it decreased once hair follicles transited to anagen stage; then it increased reversely at catagen stage. This study provided a new method to quantitatively evaluate the hair follicle stage, and should be valuable for the basic and therapeutic investigations on hair regeneration.

  20. Improvement of sensitivity in continuous wave near infra-red spectroscopy systems by using silicon photomultipliers.

    PubMed

    Pagano, Roberto; Libertino, Sebania; Sanfilippo, Delfo; Fallica, Giorgio; Lombardo, Salvatore

    2016-04-01

    We experimentally analyze the signal-to-noise ratio of continuous wave (CW) near infrared spectroscopy (NIRS) reflectance systems based on light emitting diodes and silicon photomultipliers for high performance low cost NIRS biomedical systems. We show that under suitable experimental conditions such systems exhibit a high SNR, which allows an SDS of 7 cm, to our knowledge the largest ever demonstrated in a CW-NIRs system. PMID:27486551

  1. Improvement of sensitivity in continuous wave near infra-red spectroscopy systems by using silicon photomultipliers

    PubMed Central

    Pagano, Roberto; Libertino, Sebania; Sanfilippo, Delfo; Fallica, Giorgio; Lombardo, Salvatore

    2016-01-01

    We experimentally analyze the signal-to-noise ratio of continuous wave (CW) near infrared spectroscopy (NIRS) reflectance systems based on light emitting diodes and silicon photomultipliers for high performance low cost NIRS biomedical systems. We show that under suitable experimental conditions such systems exhibit a high SNR, which allows an SDS of 7 cm, to our knowledge the largest ever demonstrated in a CW-NIRs system. PMID:27486551

  2. [Investigation of fibrous cultural materials by infrared spectroscopy].

    PubMed

    Luo, Xi-yun; Du, Yi-ping; Shen, Mei-hua; Zhang, Wen-qing; Zhou, Xin-guang; Fang, Shu-ying; Zhang, Xuan

    2015-01-01

    Cultural fibrous material includes both important categories, i. e. textile and paper, consisting of precious cultural materials in museum, such as costume, painting, and manuscript. In recent years more and more connoisseur and conservator's concerns are, through nondestructive method, the authenticity and the ageing identification of these cultural relics especially made from fragile materials. In this research, we used attenuated total reflection infrared spectroscopy to identify five traditional textile fibers, alongside cotton, linen, wool, mulberry silk and tussah silk, and another five paper fibers alongside straw, wheat straw, long qisong, Chinese alpine rush and mulberry bar, which are commonly used for making Chinese traditional xuan paper. The research result showed that the animal fiber (wool, mulberry silk and tussah silk) and plant fiber (cotton and linen) were easier to be distinguished by comparing the peaks at 3 280 cm-1 belonging to NH stretching vibration and a serious peaks related to amide I to amide III. In the spectrum of wool, the peak at 1 076 cm-1 was assigned to the S-O stretching vibration absorption of cystine in wool structure and can be used to tell wool from silk. The spectrum of mulberry silk and tussah silk seems somewhat difficult to be identified, as well as the spectrum of cotton and linen. Five rural paper fibers all have obvious characteristic peaks at 3 330, 2 900 cm-1 which are related to OH and CH stretching vibration. In the fingerprint wavenumber range of 1 600 - 800 cm, the similar peaks also appeared at 1 370, 1 320 cm-1 and 1 162, 1 050 cm-1, both group peaks respectively are related to CH and CO vibration in the structure of cellulose and hemicellulose in paper fibers. Although there is more similarity of the infrared spectroscopy of these 5 paper fibers, some tiny difference in absorbance also can be found at 3 300 cm-1 and in the fingerprint range at 1 332, 1 203, and 1 050 cm-1 which are related to C-O-C vibration

  3. Study Of A Formulated Pesticide By Photoacoustic Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lowry, S. R.; Mead, D. G.; Vidrine, D. W.

    1981-10-01

    Photoacoustic infrared spectroscopy has been used to study the interactions of a carbamate insecticide with a clay carrier. The ability of photoacoustic infrared spectroscopy to measure infrared spectra from opaque samples non-destructively, is particularly valuable in this study where weak bonds might be destroyed by sample grinding. The results of this study show that the strong N-H stretching modes, which appear at approximately 3300 cm-1 in in the pure insecticide, are missing in the subtraction of the N-H group spectrum. This suggests that the hydrogen attached to the nitrogen of the carbamate is forming a reasonably strong bond with the hydrated silicate structure of the clay carrier. This interaction may effect the release rate of the pesticide upon application.

  4. Variable Temperature Infrared Spectroscopy Investigations of Benzoic Acid Desorption from Sodium and Calcium Montmorillonite Clays.

    PubMed

    Nickels, Tara M; Ingram, Audrey L; Maraoulaite, Dalia K; White, Robert L

    2015-12-01

    Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate. PMID:26647147

  5. Infrared spectroscopy of exoplanets: observational constraints

    PubMed Central

    Encrenaz, Thérèse

    2014-01-01

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

  6. Airborne Infrared Spectroscopy of 1994 Western Wildfires

    NASA Technical Reports Server (NTRS)

    Worden, Helen; Beer, Reinhard; Rinsland, Curtis P.

    1997-01-01

    In the summer of 1994 the 0.07/ cm resolution infrared Airborne Emission Spectrometer (AES) acquired spectral data over two wildfires, one in central Oregon on August 3 and the other near San Luis Obispo, California, on August 15. The spectrometer was on board a NASA DC-8 research aircraft, flying at an altitude of 12 km. The spectra from both fires clearly show features due to water vapor, carbon dioxide, carbon monoxide, ammonia, methanol, formic acid, and ethylene at significantly higher abundance and temperature than observed in downlooking spectra of normal atmospheric and ground conditions. Column densities are derived for several species, and molar ratios are compared with previous biomass fire measurements. We believe that this is the first time such data have been acquired by airborne spectral remote sensing.

  7. Infrared spectroscopy of exoplanets: observational constraints.

    PubMed

    Encrenaz, Thérèse

    2014-04-28

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations.

  8. Computing protein infrared spectroscopy with quantum chemistry.

    PubMed

    Besley, Nicholas A

    2007-12-15

    Quantum chemistry is a field of science that has undergone unprecedented advances in the last 50 years. From the pioneering work of Boys in the 1950s, quantum chemistry has evolved from being regarded as a specialized and esoteric discipline to a widely used tool that underpins much of the current research in chemistry today. This achievement was recognized with the award of the 1998 Nobel Prize in Chemistry to John Pople and Walter Kohn. As the new millennium unfolds, quantum chemistry stands at the forefront of an exciting new era. Quantitative calculations on systems of the magnitude of proteins are becoming a realistic possibility, an achievement that would have been unimaginable to the early pioneers of quantum chemistry. In this article we will describe ongoing work towards this goal, focusing on the calculation of protein infrared amide bands directly with quantum chemical methods.

  9. Infrared spectroscopy of exoplanets: observational constraints.

    PubMed

    Encrenaz, Thérèse

    2014-04-28

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

  10. Infrared Spectroscopy of Hydrated Nitromethane Anions

    NASA Astrophysics Data System (ADS)

    Marcum, Jesse C.; Weber, J. Mathias

    2009-06-01

    The hydration of molecular anions is still not as thoroughly explored as for atomic anions. We present IR spectra and quantum chemical calculations of hydrated nitromethane anions. In the monohydrate, the nitro group of the ion interacts with the water molecule via two hydrogen bonds, one from each O atom. This motif is partially conserved in the dihydrate. Adding the third water molecule results in a ring-like structure of the water ligands, each of which forms one H bond to one of the O atoms of the nitro group and another to a neighboring water ligand, reminiscent of the hydration motif of the heavier halides. Interestingly, while the methyl group is not directly involved in the interaction with the water ligands, its infrared signature is strongly affected by the changes in the intramolecular charge distribution through hydration.

  11. Infrared spectroscopy of simulated Martian surface materials

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Sagan, C.

    1978-01-01

    Mineralogy inferred from the Viking X-ray fluorescence spectrometry (XRFS) is compared with mineralogy indicated by spectral data. The comparison is done by taking laboratory spectra of Viking analog minerals. Both XRFS and infrared data are consistent with clays as the dominant SiO2 containing minerals on Mars. The X-ray fluorescence data might also be consistent with the dominance of certain mafic SiO2 igneous minerals, but the spectral data are probably inconsistent with such materials. Sulfates, inferred by XRFS, are consistent with the spectral data. Inferences following Mariner 9 that high-SiO2 minerals were important on Mars may have been biased by the presence of sulfates. Calcium carbonate, in the quantities indirectly suggested by XRFS are inconsistent with the spectral data, but smaller quantities of CaCO3 are consistent, as are large quantities of other carbonates.

  12. Stratospheric sounding by infrared heterodyne spectroscopy

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kunde, V. G.; Mumma, M. J.; Kostiuk, T.; Buhl, D.; Frerking, M. A.

    1978-01-01

    Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution. The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes, and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described and applications to synthetic lines of O3, CO2, CH4 and N2O are given.

  13. Near-infrared spectroscopy in NGC 7538

    NASA Astrophysics Data System (ADS)

    Puga, E.; Marín-Franch, A.; Najarro, F.; Lenorzer, A.; Herrero, A.; Acosta Pulido, J. A.; Chavarría, L. A.; Bik, A.; Figer, D.; Ramírez Alegría, S.

    2010-07-01

    Aims: The characterisation of the stellar population in young high-mass star-forming regions allows fundamental cluster properties like distance and age to be constrained. These are essential when using high-mass clusters as probes for conducting Galactic studies. Methods: NGC 7538 is a star-forming region with an embedded stellar population unearthed only in the near-infrared (NIR). We present the first near-infrared spectro-photometric study of the candidate high-mass stellar content in NGC 7538. We obtained H and K spectra of 21 sources with both the multi-object and long-slit modes of LIRIS at the WHT, and complement these data with subarcsecond JHKs photometry of the region using the imaging mode of the same instrument. Results: We find a wide variety of objects within the studied stellar population of NGC 7538. Our results discriminate between a stellar population associated to the H ii region, but not contained within its extent, and several pockets of more recent star formation. We report the detection of CO bandhead emission toward several sources, as well as other features indicative of a young stellar nature. We infer a spectro-photometric distance of 2.7 ± 0.5 kpc, an age spread in the range 0.5-2.2 Myr and a total mass 1.7 × 103 Msun for the older population. Based on observations made with the WHT operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

  14. Bird sexing by Fourier transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Steiner, Gerald; Bartels, Thomas; Krautwald-Junghanns, Maria-Elisabeth; Koch, Edmund

    2010-02-01

    Birds are traditionally classified as male or female based on their anatomy and plumage color as judged by the human eye. Knowledge of a bird's gender is important for the veterinary practitioner, the owner and the breeder. The accurate gender determination is essential for proper pairing of birds, and knowing the gender of a bird will allow the veterinarian to rule in or out gender-specific diseases. Several biochemical methods of gender determination have been developed for avian species where otherwise the gender of the birds cannot be determined by their physical appearances or characteristics. In this contribution, we demonstrate that FT-IR spectroscopy is a suitable tool for a quick and objective determination of the bird's gender. The method is based on differences in chromosome size. Male birds have two Z chromosomes and female birds have a W-chromosome and a Z-chromosome. Each Z-chromosome has approx. 75.000.000 bps whereas the W-chromosome has approx. 260.00 bps. This difference can be detected by FT-IR spectroscopy. Spectra were recorded from germ cells obtained from the feather pulp of chicks as well as from the germinal disk of fertilized but non-bred eggs. Significant changes between cells of male and female birds occur in the region of phosphate vibrations around 1080 and 1120 cm-1.

  15. Metal nanofilms studied with infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Fahsold, Gerhard; Priebe, Andreas; Pucci, Annemarie; Otto, Andreas

    2006-03-01

    Metal films with thickness in the nanometer range are optically transparent. In the IR range their transmittance may show both the Drude-type behaviour of coalesced islands and the tail of the plasmon absorption of single islands. Therefore, IR transmittance spectroscopy is a sensitive tool for in-situ studies of metal-film growth on insulating substrates and of the film conductivity. With IR transmittance spectroscopy the in-plane film conductivity and its correlation to the film-growth process can be determined without electrical contacts. Adsorbate induced changes can be observed well. Their analysis may give insight into the adsorbate-metal bonding. Depending on the film's roughness the IR lines of adsorbate-vibration modes may be strongly modified because of their interaction with electronic excitations of the film. The atomic roughness of cold-condensed metal films produces additional IR activity: strong IR activity of Raman lines of centrosymmetric adsorbate molecules is observed in those cases where the adsorbate has states close to the Fermi level.

  16. Visible and near infrared reflectances measured from laboratory ice clouds.

    PubMed

    Barkey, Brian; Liou, K N

    2008-05-01

    We present laboratory results of the 0.68 microm visible (VIS) and 1.617 microm near infrared (NIR) reflectances typically used for inferring optical depth and ice crystal size from satellite radiometers, from ice clouds generated in a temperature controlled column cloud chamber. Two types of ice crystals were produced in this experiment: small columns and dendrites with mean maximum dimensions of about 17 and 35 microm. Within experimental uncertainty, the measured reflectances from ice clouds at both wavelengths agree reasonably well with the theoretical results computed from the plane-parallel adding-doubling method for radiative transfer using the measured ice particle morphology. We demonstrate that laboratory scattering and reflectance data for thin ice clouds with optical depths less than 0.4 can be used for validation of the thin cirrus optical depth and ice crystal size that have been routinely retrieved from the satellite VIS-NIR two channel pair.

  17. Visible and near infrared reflectances measured from laboratory ice clouds.

    PubMed

    Barkey, Brian; Liou, K N

    2008-05-01

    We present laboratory results of the 0.68 microm visible (VIS) and 1.617 microm near infrared (NIR) reflectances typically used for inferring optical depth and ice crystal size from satellite radiometers, from ice clouds generated in a temperature controlled column cloud chamber. Two types of ice crystals were produced in this experiment: small columns and dendrites with mean maximum dimensions of about 17 and 35 microm. Within experimental uncertainty, the measured reflectances from ice clouds at both wavelengths agree reasonably well with the theoretical results computed from the plane-parallel adding-doubling method for radiative transfer using the measured ice particle morphology. We demonstrate that laboratory scattering and reflectance data for thin ice clouds with optical depths less than 0.4 can be used for validation of the thin cirrus optical depth and ice crystal size that have been routinely retrieved from the satellite VIS-NIR two channel pair. PMID:18449323

  18. Improved Spatial Resolution for Reflection Mode Infrared Microscopy

    SciTech Connect

    Bechtel, Hans A.; Martin, Michael C.; May, T.E.; Lerch, Philippe

    2009-10-09

    Standard commercial infrared microscopes operating in reflection mode use a mirror to direct the reflected light from the sample to the detector. This mirror blocks about half of the incident light, however, and thus degrades the spatial resolution by reducing the umerical aperture of the objective. Here, we replace the mirror with a 50% beamsplitter to allow full illumination of the objective and retain a way to direct the reflected light to the detector. The improved spatial resolution is demonstrated using two different microscopes apable of diffraction-limited resolution: the first microscope is coupled to a synchrotron source and utilizes a single point detector, whereas the second microscope has a standard blackbody source and uses a focal planetarray (FPA) detector.

  19. Reflected infrared spectrum of a massive protostar in Orion.

    PubMed

    Morino, J I; Yamashita, T; Hasegawa, T; Nakano, T

    1998-05-28

    The infrared source IRc2 in the star-forming region Orion-KL is generally believed to contain a massive and very young star. Its nature and evolutionary status, however, are difficult to determine because it is hidden from direct view by a dense disklike envelope of gas and dust. Here we report observations of infrared radiation (at a wavelength of about 2 microm) that has escaped the surrounding dust in the polar direction, perpendicular to the plane of the disk, and then been reflected towards us by dust farther away from the star. The reflected spectrum contains absorption lines of neutral metallic atoms and carbon monoxide, which we interpret as indicating a source temperature of about 4,500 K. But, given the luminosity of the source, its radius must be at least 300 solar radii-too large to be attained with the modest gas-accretion rates in existing theories of massive-star formation. Whether the infrared radiation is coming from the protostar itself or the self-luminous accretion disk around it, the accretion rate must be around (5-15) x 10(-3) solar masses per year, at least two orders of magnitude greater than is commonly assumed in models of star formation.

  20. Assessment of skin flap viability using visible diffuse reflectance spectroscopy and auto-fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhu, Caigang; Chen, Shuo; Chui, Christopher Hoe-Kong; Liu, Quan

    2012-12-01

    The accurate assessment of skin flap viability is vitally important in reconstructive surgery. Early identification of vascular compromise increases the change of successful flap salvage. The ability to determine tissue viability intraoperatively is also extremely useful when the reconstructive surgeon must decide how to inset the flap and whether any tissue must be discarded. Visible diffuse reflectance and auto-fluorescence spectroscopy, which yield different sets of biochemical information, have not been used in the characterization of skin flap viability simultaneously to our best knowledge. We performed both diffuse reflectance and fluorescence measurements on a reverse MacFarlane rat dorsal skin flap model to identify the additional value of auto-fluorescence spectroscopy to the assessment of flap viability. Our result suggests that auto-fluorescence spectroscopy appears to be more sensitive to early biochemical changes in a failed flap than diffuse reflectance spectroscopy, which could be a valuable complement to diffuse reflectance spectroscopy for the assessment of flap viability.

  1. Infrared Spectroscopy of Black Hole Candidates

    NASA Astrophysics Data System (ADS)

    Colgan, S. W. J.; Cotera, A. S.; Maloney, P. R.; Hollenbach, D. J.

    2000-05-01

    ISO LWS and SWS observations of the solar mass black hole candidates 1E1740.7-2942 and GRS1758-258 are presented. For 1E1740.7-2942, it has been suggested that the luminosity is provided in whole or part by Bondi-Hoyle accretion from a surrounding black hole (Bally & Leventhal 1991, Nat, 353, 234). Maloney etal. (1997, ApJ 482, L41) have predicted that detectable far-infrared line emission from [OI] (63 microns), [CII] (158 microns), [SiII] (35 microns) and other lines will arise from black holes which are embedded in molecular clouds. No strong line emission associated with either 1E1740.7-2942 or GRS1758-258 was detected, implying either that 1) these sources are not embedded in dense molecular clouds, or 2) that their average X-ray luminosity over the past 100 years is significantly lower than its current value. The measured upper limits to the line fluxes are compared with the models of Maloney etal. to constrain the properties of the ISM in the vicinity of these X-ray sources. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.

  2. High spectral resolution reflectance spectroscopy of minerals

    NASA Technical Reports Server (NTRS)

    Clark, Roger N.; King, Trude V. V.; Klejwa, Matthew; Swayze, Gregg A.; Vergo, Norma

    1990-01-01

    The reflectance spectra of minerals are studied as a function of spectral resolution in the range from 0.2 to 3.0 microns. Selected absorption bands were studied at resolving powers as high as 2240. At resolving powers of approximately 1000, many OH-bearing minerals show diagnostic sharp absorptions at the resolution limit. At low resolution, some minerals may not be distinguishable, but as the resolution is increased, most can be easily identified. As the resolution is increased, many minerals show fine structure, particularly in the OH-stretching overtone region near 1.4 micron. The fine structure can enhance the ability to discriminate between minerals, and in some cases the fine structure can be used to determine elemental composition.

  3. Diffuse reflectance spectroscopy of fibrous proteins.

    PubMed

    Millington, Keith R

    2012-09-01

    UV-visible diffuse reflectance (DR) spectra of the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen are presented. Natural wool contains much higher levels of visible chromophores across the whole visible range (700-400 nm) than the other proteins and only those above 450 nm are effectively removed by bleaching. Both oxidative and reductive bleaching are inefficient for removing yellow chromophores (450-400 nm absorbers) from wool. The DR spectra of the four UV-absorbing amino acids tryptophan, tyrosine, cystine and phenylalanine were recorded as finely ground powders. In contrast to their UV-visible spectra in aqueous solution where tryptophan and tyrosine are the major UV absorbing species, surprisingly the disulphide chromophore of solid cystine has the strongest UV absorbance measured using the DR remission function F(R)(∞). The DR spectra of unpigmented feather and wool keratin appear to be dominated by cystine absorption near 290 nm, whereas silk fibroin appears similar to tyrosine. Because cystine has a flat reflectance spectrum in the visible region from 700 to 400 nm and the powder therefore appears white, cystine absorption does not contribute to the cream colour of wool despite the high concentration of cystine residues near the cuticle surface. The disulphide absorption of solid L: -cystine in the DR spectrum at 290 nm is significantly red shifted by ~40 nm relative to its wavelength in solution, whereas homocystine and lipoic acid showed smaller red shifts of 20 nm. The large red shift observed for cystine and the large difference in intensity of absorption in its UV-visible and DR spectra may be due to differences in the dihedral angle between the crystalline solid and the solvated molecules in solution. PMID:22218994

  4. Diffuse reflectance spectroscopy of fibrous proteins.

    PubMed

    Millington, Keith R

    2012-09-01

    UV-visible diffuse reflectance (DR) spectra of the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen are presented. Natural wool contains much higher levels of visible chromophores across the whole visible range (700-400 nm) than the other proteins and only those above 450 nm are effectively removed by bleaching. Both oxidative and reductive bleaching are inefficient for removing yellow chromophores (450-400 nm absorbers) from wool. The DR spectra of the four UV-absorbing amino acids tryptophan, tyrosine, cystine and phenylalanine were recorded as finely ground powders. In contrast to their UV-visible spectra in aqueous solution where tryptophan and tyrosine are the major UV absorbing species, surprisingly the disulphide chromophore of solid cystine has the strongest UV absorbance measured using the DR remission function F(R)(∞). The DR spectra of unpigmented feather and wool keratin appear to be dominated by cystine absorption near 290 nm, whereas silk fibroin appears similar to tyrosine. Because cystine has a flat reflectance spectrum in the visible region from 700 to 400 nm and the powder therefore appears white, cystine absorption does not contribute to the cream colour of wool despite the high concentration of cystine residues near the cuticle surface. The disulphide absorption of solid L: -cystine in the DR spectrum at 290 nm is significantly red shifted by ~40 nm relative to its wavelength in solution, whereas homocystine and lipoic acid showed smaller red shifts of 20 nm. The large red shift observed for cystine and the large difference in intensity of absorption in its UV-visible and DR spectra may be due to differences in the dihedral angle between the crystalline solid and the solvated molecules in solution.

  5. Immersion Gratings for Infrared High-resolution Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sarugaku, Yuki; Ikeda, Yuji; Kobayashi, Naoto; Kaji, Sayumi; Sukegawa, Takashi; Sugiyama, Shigeru; Nakagawa, Takao; Arasaki, Takayuki; Kondo, Sohei; Nakanishi, Kenshi; Yasui, Chikako; Kawakita, Hideyo

    2016-10-01

    High-resolution spectroscopy in the infrared wavelength range is essential for observations of minor isotopologues, such as HDO for water, and prebiotic organic molecules like hydrocarbons/P-bearing molecules because numerous vibrational molecular bands (including non-polar molecules) are located in this wavelength range. High spectral resolution enables us to detect weak lines without spectral line confusion. This technique has been widely used in planetary sciences, e.g., cometary coma (H2O, CO, and organic molecules), the martian atmosphere (CH4, CO2, H2O and HDO), and the upper atmosphere of gas giants (H3+ and organic molecules such as C2H6). Spectrographs with higher resolution (and higher sensitivity) still have a potential to provide a plenty of findings. However, because the size of spectrographs scales with the spectral resolution, it is difficult to realize it.Immersion grating (IG), which is a diffraction grating wherein the diffraction surface is immersed in a material with a high refractive index (n > 2), provides n times higher spectral resolution compared to a reflective grating of the same size. Because IG reduces the size of spectrograph to 1/n compared to the spectrograph with the same spectral resolution using a conventional reflective grating, it is widely acknowledged as a key optical device to realize compact spectrographs with high spectral resolution.Recently, we succeeded in fabricating a CdZnTe immersion grating with the theoretically predicted diffraction efficiency by machining process using an ultrahigh-precision five-axis processing machine developed by Canon Inc. Using the same technique, we completed a practical germanium (Ge) immersion grating with both a reflection coating on the grating surface and the an AR coating on the entrance surface. It is noteworthy that the wide wavelength range from 2 to 20 um can be covered by the two immersion gratings.In this paper, we present the performances and the applications of the immersion

  6. Infrared Spectroscopy of Alanine in Solid Parahydrogen

    NASA Astrophysics Data System (ADS)

    Toh, Shin Yi; Wong, Ying-Tung Angel; Djuricanin, Pavle; Momose, Takamasa

    2014-06-01

    Amino acids are the building blocks of biological molecules, and thus the investigation of their physical and chemical properties would allow for further understanding of their functions in biological systems. In addition, the existence of amino acids in interstellar space has been discussed for many years, but it is still under intense debate. The effect of UV radiation on amino acids is one of the keys for their search in interstellar space, where strong UV radiation exists. In this experiment, conformational compositions of alpha and beta alanine and their UV photolysis were investigated via matrix-isolation FTIR spectroscopy and quantum chemical calculations. Solid parahydrogen was used as the matrix, which provides higher resolution spectra than other noble gas matrices. We have identified several stable conformers for both alpha and beta alanine in solid parahydrogen. A clear correlation between conformational ratio and sublimation temperature was found for beta alanine. Furthermore, it was found that UV photolysis of alanine yields not only its conformational changes, but also photodissociation into a CO2 molecule and fragments. Observed spectra and their analysis will be discussed in relation to interstellar chemistry.

  7. Development of techniques for advanced optical contamination measurement with internal reflection spectroscopy, phase 1, volume 1

    NASA Technical Reports Server (NTRS)

    Hayes, J. D.

    1972-01-01

    The feasibility of monitoring volatile contaminants in a large space simulation chamber using techniques of internal reflection spectroscopy was demonstrated analytically and experimentally. The infrared spectral region was selected as the operational spectral range in order to provide unique identification of the contaminants along with sufficient sensitivity to detect trace contaminant concentrations. It was determined theoretically that a monolayer of the contaminants could be detected and identified using optimized experimental procedures. This ability was verified experimentally. Procedures were developed to correct the attenuated total reflectance spectra for thick sample distortion. However, by using two different element designs the need for such correction can be avoided.

  8. Study of laser reflection of infrared cameras with germanium optics

    NASA Astrophysics Data System (ADS)

    Chiu, Patrio; Shih, Ishiang; Shi, S.; Laou, Philips

    2003-09-01

    Infrared cameras are widely used in today's battlefield for surveillance purpose. Because of retroreflection, an incident laser beam entering the camera optics results in a beam reflecting back to the direction of the laser source. An IR detector positioned close to the laser source can then detect the reflected beam. This effect can reveal the location of the cameras and thus increases the risk of covert operations. In the present work, the characteristics of the retroreflection is studied. It is found that the reflection intensity is high when the incident beam enters through the middle part of the lenses while it is low and the beam is diverged when entering through the outer part of the lenses. The reflection is symmetric when the incident beam is normal to the lenses while asymmetric when it is incident with an angle to the lenses. In order to study the potential effects on retroreflection of modified camera optics, IR low index slides (ZnSe and KCl with refractive indices of 2.49 and 1.54, respectively) with different thicknesses (2mm, 4mm and 6mm) are placed in the optical system. The result shows that the focal point of the lenses is changed by the addition of the slide but the optical paths of the reflection remain unchanged. The relationship between the different slides and beam intensity is also studied.

  9. Infrared reflectance spectra (2. 2-15. mu. m) of plagioclase feldspars

    SciTech Connect

    Nash, D.B. ); Salisbury, J.W. )

    1991-06-01

    Laboratory results show that (1) the Christiansen frequency (CF) feature in mid-infrared reflectance spectra of powders can be used to accurately distinguish plagioclase composition, and (2) the wavelength position of the CF is not affected by vitrification of the plagioclase. Although the CF position does not distinguish glass from crystalline forms of plagioclase, other features (combination-tone, overtone, restrahlen bands) in the mid-IR spectra of plagioclase can be used for that purpose. These results have important implications for application of thermal emission spectroscopy to mapping the surface composition of regolith-covered planetary bodies like the Moon, Mars, and asteroids.

  10. Breast phantom for mammary tissue characterization by near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Miranda, D. A.; Cristiano, K. L.; Gutiérrez, J. C.

    2013-11-01

    Breast cancer is a disease associated to a high morbidity and mortality in the entire world. In the study of early detection of breast cancer the development of phantom is so important. In this research we fabricate a breast phantom using a ballistic gel with special modifications to simulate a normal and abnormal human breast. Optical properties of woman breast in the near infrared region were modelled with the phantom we developed. The developed phantom was evaluated with near infrared spectroscopy in order to study its relation with breast tissue. A good optical behaviour was achieved with the model fabricated.

  11. Synchrotron-based far-infrared spectroscopy of nickel tungstate

    NASA Astrophysics Data System (ADS)

    Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R. A.

    2016-07-01

    Monoclinic antiferromagnetic NiWO4 was studied by far-infrared (30-600 cm-1) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO4 and ZnWO4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO4 and CoWO4 below their Neel temperatures down to 5 K.

  12. Atomic Force Microscopy and Infrared Spectroscopy Studies of Hydrogen Baked Si Surfaces

    NASA Astrophysics Data System (ADS)

    Vatel, Olivier; Verhaverbeke, Steven; Bender, Hugo; Caymax, Matty; Chollet, Frederic; Vermeire, Bert; Mertens, Paul; André, Elie; Heyns, Marc

    1993-10-01

    A H2 pre-bake at temperatures over 1050°C is typically used prior to Si epitaxial growth. In this study surface microroughness probed with tapping mode Atomic Force Microscopy (AFM) is correlated with multiple internal reflection infrared spectroscopy measurements for the different steps involved before epitaxy. A novel sample preparation technique was used for the multiple internal reflection set-up. A strong correlation was found between the presence of surface terraces and the IR double monohydride peaks for H2 annealed Si surfaces. We therefore put forward that the terraces are due to the H2 pre-bake step. These terraces remain after epitaxial deposition.

  13. Charge modulation infrared spectroscopy of rubrene single-crystal field-effect transistors

    NASA Astrophysics Data System (ADS)

    Uchida, R.; Yada, H.; Makino, M.; Matsui, Y.; Miwa, K.; Uemura, T.; Takeya, J.; Okamoto, H.

    2013-03-01

    Polarized absorption spectra of hole carriers in rubrene single crystal field-effect transistors were measured in the infrared region (725-8000 cm-1) by charge modulation spectroscopy. The absorptions, including the superimposed oscillatory components due to multiple reflections within thin crystals, monotonically increased with decreasing frequency. The spectra and their polarization dependences were well reproduced by the analysis based on the Drude model, in which the absorptions due to holes in rubrene and electrons in the gate electrodes (silicon), and multiple reflections were fully considered. The results support the band transport of hole carriers in rubrene.

  14. Evaluation of Phalaenopsis flowering quality using near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Suming; Chuang, Yung-Kun; Tsai, Chao-Yin; Chang, Yao-Chien A.; Yang, I.-Chang; Chang, Yung-Huei; Tai, Chu-Chun; Hou, Jiunn-Yan

    2013-05-01

    Carbohydrate contents have been demonstrated as indicators for flowering quality of Phalaenopsis plants. In this study, near infrared reflectance (NIR) spectroscopy was employed for quantitative analysis of carbohydrate contents like fructose, glucose, sucrose, and starch in Phalaenopsis. The modified partial least squares regression (MPLSR) method was adopted for spectra analyses of 176 grown plant samples (88 shoots and 88 roots), over the full wavelength range (FWR, 400 to 2498 nm). For fructose concentrations, the smoothing 1st derivative model can produce the best effect (Rc = 0.961, SEC = 0.210% DW, SEV = 0.324% DW) in the wavelength ranges of 1400-1600, 1800-2000, and 2200-2300 nm. For glucose concentrations, the smoothing 1st derivative model can produce the best effect (Rc = 0.975, SEC = 0.196% DW, SEV = 0.264% DW) in the wavelength range of 1400-1600, 1800-2000, and 2100-2400 nm. For sucrose concentrations, the smoothing 1st derivative model can produce the best effect (Rc = 0.961, SEC = 0.237% DW, SEV = 0.322% DW) in the wavelength range of 1300-1400, 1500-1800, 2000-2100, and 2200-2300 nm. For starch concentrations, the smoothing 1st derivative model can produce the best effect (Rc = 0.873, SEC = 0.697% DW, SEV = 0.774% DW) in the wavelength ranges of 500-700, 1200-1300, 1700-1800, and 2200-2300 nm. This study successfully developed the calibration models for inspecting concentrations of carbohydrates to predict the flowering quality in different cultivation environments of Phalaenopsis. The specific wavelengths can be used to predict the quality of Phalaenopsis flowers and thus to adjust cultivation managements.

  15. High reflected cubic cavity as long path absorption cell for infrared gas sensing

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Gao, Qiang; Zhang, Zhiguo

    2014-10-01

    One direct and efficient method to improve the sensitivity of infrared gas sensors is to increase the optical path length of gas cells according to Beer-Lambert Law. In this paper, cubic shaped cavities with high reflected inner coating as novel long path absorption cells for infrared gas sensing were developed. The effective optical path length (EOPL) for a single cubic cavity and tandem cubic cavities were investigated based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) measuring oxygen P11 line at 763 nm. The law of EOPL of a diffuse cubic cavity in relation with the reflectivity of the coating, the port fraction and side length of the cavity was obtained. Experimental results manifested an increase of EOPL for tandem diffuse cubic cavities as the decrease of port fraction of the connecting aperture f', and the EOPL equaled to the sum of that of two single cubic cavities at f'<0.01. The EOPL spectra at infrared wavelength range for different inner coatings including high diffuse coatings and high reflected metallic thin film coatings were deduced.

  16. Photo-induced reflectivity in the mid and far infrared

    SciTech Connect

    Haar, P.; Harrington, K.J.; Schwettman, H.A.

    1995-12-31

    Interest in switching FEL beams has motivated studies of photo-induced reflectivity in the mid and far infrared. We are particularly interested in Ge{sup 4}, GaAs, and Si{sup 5}, materials that can be pumped with a visible or near-IR conventional laser and which together cover the wavelengths from 3-100{mu}m. We have made quantitative measurements to determine the induced reflectivity, carrier lifetime, and transient absorption of these materials at several wavelengths across this range using a variety of pump laser wavelengths and pulse lengths. These measurements allow us to determine the feasibility of single pulse selection and cavity dumping with our FELs at high repetition rates.

  17. Far-infrared emissivity measurements of reflective surfaces

    NASA Technical Reports Server (NTRS)

    Xu, J.; Lange, A. E.; Bock, J. J.

    1996-01-01

    An instrument developed to measure the emissivity of reflective surfaces by comparing the thermal emission of a test sample to that of a reference surface is reported. The instrument can accurately measure the emissivity of mirrors made from lightweight thermally insulating materials such as glass and metallized carbon fiber reinforced plastics. Far infrared measurements at a wavelength of 165 micrometers are reported. The instrument has an absolute accuracy of Delta epsilon = 9 x 10(exp -4) and can reproducibly measure an emissivity of as small as 2 x 10(exp -4) between flat reflective surfaces. The instrument was used to measure mirror samples for balloon-borne and spaceborne experiments. An emissivity of (6.05 +/- 1.24) x 10(exp -3) was measured for gold evaporated on glass, and (6.75 +/- 1.17) x 10(exp -3) for aluminum evaporated on glass.

  18. Apollo 17 Soil Characterization for Reflectance Spectroscopy

    NASA Technical Reports Server (NTRS)

    Taylor, L. A.; Pieters, C.; Patchen, A.; Morris, R. V.; Keller, L. P.; Wentworth, S.; McKay, D. S.

    1999-01-01

    It is the fine fractions that dominate the observed spectral signatures of bulk lunar soil, and the next to the smallest size fractions are the most similar to the overall properties of the bulk soil. Thus, our Lunar Soil Characterization Consortium has concentrated on understanding the inter-relations of compositional, mineralogical, and optical properties of the <45-micron size fraction and its component sizes (20-44 micron, 10-20 micron, and <10 micron size fractions). To be able to generalize our results beyond the particular sample set studied, it is necessary to quantitatively identify the observed effects of space weathering and evaluate the processes involved. For this, it is necessary to know the chemistry of each size fraction, modal abundances of each phase, average compositions of the minerals and glasses, I(sub s)/FeO values, reflectance spectra, and the physical makeup of the individual particles and their patinas. This characterization includes the important dissection of the pyroxene minerals into four separate populations, with data on both modes and average chemical compositions. Armed with such data, it should be possible to effectively isolate spectral effects of space weathering from spectral properties related to mineral and glass chemistry. Four mare soils from the Apollo 17 site were selected for characterization based upon similarities in bulk composition and their contrasting maturities, ranging from immature to submature to mature. The methodology of our characterization has been discussed previously. Results of the Apollo 17 mare soils, outlined herein, are being prepared for publication in MAPS. As shown, with decreasing grain size, the agglutinitic (impact) glass content profoundly increases. This is the most impressive change for the mare soils. In several soils we have examined, there is an over two-fold increase in the agglutinitic glass contents between the 90-150- micron and the 10-20-micron size fractions. Accompanying this

  19. Combined use of visible, reflected infrared, and thermal infrared images for mapping Hawaiian lava flows

    NASA Technical Reports Server (NTRS)

    Abrams, Michael; Abbott, Elsa; Kahle, Anne

    1991-01-01

    The weathering of Hawaiian basalts is accompanied by chemical and physical changes of the surfaces. These changes have been mapped using remote sensing data from the visible and reflected infrared and thermal infrared wavelength regions. They are related to the physical breakdown of surface chill coats, the development and erosion of silica coatings, the oxidation of mafic minerals, and the development of vegetation cover. These effects show systematic behavior with age and can be mapped using the image data and related to relative ages of pahoehoe and aa flows. The thermal data are sensitive to silica rind development and fine structure of the scene; the reflectance data show the degree of oxidation and differentiate vegetation from aa and cinders. Together, data from the two wavelength regions show more than either separately. The combined data potentially provide a powerful tool for mapping basalt flows in arid to semiarid volcanic environments.

  20. Study on Senna alata and its different extracts by Fourier transform infrared spectroscopy and two-dimensional correlation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Adiana, M. A.; Mazura, M. P.

    2011-04-01

    Senna alata L. commonly known as candle bush belongs to the family of Fabaceae and the plant has been reported to possess anti-inflammatory, analgesic, laxative and antiplatelet-aggregating activity. In order to develop a rapid and effective analysis method for studying integrally the main constituents in the medicinal materials and their extracts, discriminating the extracts from different extraction process, comparing the categories of chemical constituents in the different extracts and monitoring the qualities of medicinal materials, we applied Fourier transform infrared spectroscopy (FT-IR) associated with second derivative infrared spectroscopy and two-dimensional infrared correlation spectroscopy (2D-IR) to study the main constituents of S. alata and its different extracts (extracted by hexane, dichloromethane, ethyl acetate and methanol in turn). The findings indicated that FT-IR and 2D-IR can provide many holistic variation rules of chemical constituents. Use of the macroscopical fingerprint characters of FT-IR and 2D-IR spectrum can identify the main chemical constituents in medicinal materials and their extracts, but also compare the components differences among similar samples. In a conclusion, FT-IR spectroscopy combined with 2D correlation analysis provides a powerful method for the quality control of traditional medicines.

  1. Noninvasive detection of gas exchange rate by near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Guodong; Mao, Zongzhen; Wang, Bangde

    2008-12-01

    In order to study the relationship among the oxygen concentration in skeletal muscle tissues and the heart rate (HR), oxygen uptake (VO2), respiratory exchange ratio (RER) during incremental running exercises on a treadmill, a near-infrared spectroscopy muscle oxygen monitor system is employed to measure the relative change in muscle oxygenation, with the heart rate, oxygen uptake, production of carbon dioxide (VCO2) and respiratory exchange ratio are recorded synchronously. The results indicate parameters mentioned above present regular changes during the incremental exercise. High correlations are discovered between relative change of oxy-hemoglobin concentration and heart rate, oxygen uptake, respiratory exchange ratio at the significance level (P=0.01). This research might introduce a new measurement technology and/or a novel biological monitoring parameter to the evaluation of physical function status, control the training intensity, estimation of the effectiveness of exercise. Keywords: near-infrared spectroscopy; muscle oxygen concentration; heart rate; oxygen uptake; respiratory exchange ratio.

  2. Pentachlorodibenzo-p-dioxin isomer differentiation by capillary gas chromatography fourier transform infrared spectroscopy

    SciTech Connect

    Grainger, J.; Reddy, V.V.; Patterson, D.G. Jr. )

    1988-09-01

    Analysis of polychlorinated dibenzo-p-dioxin (PCDD) isomers has been the focus of a number of recent investigations due to the extreme toxicities of specific laterally tetrachlorinated isomers. These investigations have primarily been directed toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), the most toxic PCDD isomer and toward isomer differentiation of TCDD isomers as a group. With the exception of pentachlorodibenzo-p-dioxin (PnCDD) isomer specific determinations based on calculated retention indices, isomer differentiation of the 14 PnCDD isomers has not been reported although 1,2,3,7,8-PnCDD is nearly as toxic as 2,3,7,8-TCDD. Chromatographically independent methods for PCDD isomer assignment have been reported by x-ray powder diffraction, proton nuclear magnetic resonance ({sup 1}H NMR), gas chromatography/matrix isolation Fourier transform infrared (MI/FTIR) spectroscopy, diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy and gas chromatography/Fourier transform infrared (GC/FTIR) spectroscopy. Although TCDD isomer assignments by the various methods are substantially in agreement, some differences are yet to be resolved. Vapor-phase reference infrared spectra are presented for the 14 PnCDD isomers. These spectra were recorded from low (< 10) microgram quantities for each isomer. The spectrum of each isomer is unique, allowing for positive isomer identification and individual group frequency absorption characteristics as a function of isomer structure.

  3. [Near infrared spectroscopy study on water content in turbine oil].

    PubMed

    Chen, Bin; Liu, Ge; Zhang, Xian-Ming

    2013-11-01

    Near infrared (NIR) spectroscopy combined with successive projections algorithm (SPA) was investigated for determination of water content in turbine oil. Through the 57 samples of different water content in turbine oil scanned applying near infrared (NIR) spectroscopy, with the water content in the turbine oil of 0-0.156%, different pretreatment methods such as the original spectra, first derivative spectra and differential polynomial least squares fitting algorithm Savitzky-Golay (SG), and successive projections algorithm (SPA) were applied for the extraction of effective wavelengths, the correlation coefficient (R) and root mean square error (RMSE) were used as the model evaluation indices, accordingly water content in turbine oil was investigated. The results indicated that the original spectra with different water content in turbine oil were pretreated by the performance of first derivative + SG pretreatments, then the selected effective wavelengths were used as the inputs of least square support vector machine (LS-SVM). A total of 16 variables selected by SPA were employed to construct the model of SPA and least square support vector machine (SPA-LS-SVM). There is 9 as The correlation coefficient was 0.975 9 and the root of mean square error of validation set was 2.655 8 x 10(-3) using the model, and it is feasible to determine the water content in oil using near infrared spectroscopy and SPA-LS-SVM, and an excellent prediction precision was obtained. This study supplied a new and alternative approach to the further application of near infrared spectroscopy in on-line monitoring of contamination such as water content in oil.

  4. Spectral infrared hemispherical reflectance measurements for LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Wood, Bobby E.; Cromwell, Brian K.; Pender, Charles W.; Shepherd, Seth D.

    1992-01-01

    This paper describes infrared hemispherical reflectance measurements (2-15 microns) that were made on 58 chromic acid anodized tray clamps retrieved from the LDEF spacecraft. These clamps were used for maintaining the experiments in place and were located at various locations about the spacecraft. Changes in reflectance of the tray clamps at these locations were compared with atomic oxygen fluxes at the same locations. A decrease in absorption band depth was seen for the surfaces exposed to space indicating that there was some surface layer erosion. In all of the surfaces measured, little evidence of contamination was observed and none of the samples showed evidence of the brown nicotine stain that was so prominent in other experiments. Total emissivity values were calculated for both exposed and unexposed tray clamp surfaces. Only small differences, usually less than 1 percent, were observed. The spectral reflectances were measured using a hemi-ellipsoidal mirror reflectometer matched with an interferometer spectrometer. The rapid scanning capability of the interferometer allowed the reflectance measurements to be made in a timely fashion. The ellipsoidal mirror has its two foci separated by 2 inches and located on the major axis. A blackbody source was located at one focus while the tray clamp samples were located at the conjugate focus. The blackbody radiation was modulated and then focused by the ellipsoid onto the tray clamps. Radiation reflected from the tray clamp was sampled by the interferometer by viewing through a hole in the ellipsoid. A gold mirror (reflectance approximately 98 percent) was used as the reference surface.

  5. Nanoscale Spectroscopy with a Scanning Near-Field Infrared Microscope

    NASA Astrophysics Data System (ADS)

    Michaels, Chris; Richter, Lee; Cavanagh, Richard; Stranick, Stephan

    2001-03-01

    The development of a scanning near-field microscope that allows the measurement of infrared spectra with nanoscale spatial resolution will be described. This instrument couples the spatial resolution of a scanning probe microscope with the chemical specificity of vibrational spectroscopy. This combination allows the in situ mapping of chemical functional groups with subwavelength spatial resolution. Infrared transmission images of a micropatterned thin gold film will be presented that demonstrate spatial resolution of λ/10 at 3.4 micrometers in the absence of artifacts due to topography-induced contrast. Near-field infrared absorption spectra of thin polymer films that demonstrate sensitivity sufficient for sub-diffraction absorption imaging in the aliphatic and aromatic C-H stretching regions will also be presented. Images of thin film polymer blends and nanocomposites acquired in the C-H stretching region will be used to benchmark the nanoscale chemical imaging capabilities of this microscope.

  6. In vivo time-resolved multidistance near infra-red spectroscopy of adult heads: time shift tolerance of measured reflectance to suppress the coupling between absorption and reduced scattering coefficients

    NASA Astrophysics Data System (ADS)

    Tanifuji, T.; Sakai, D.

    2015-03-01

    The absorption and reduced scattering coefficients ( μa and μ's) of adult heads were determined by multidistance timeresolved reflectance measurements. The finite difference time domain analysis was used to calculate the time-resolved reflectance from adult head models. In vivo time-resolved reflectances of human heads was measured at wavelengths of 680 and 780 nm. By minimizing the objective functions that compare the theoretical and experimental time-resolved reflectances, μa and μ's of the brains were determined. The results show that the time shift tolerance of measured reflectance for reducing to less than 10% the deviations in μa and μ's due to their coupling from the values obtained by optimum time shifts is more than 20 ps at both wavelengths.

  7. Utilization of functional near infrared spectroscopy for non-invasive evaluation

    NASA Astrophysics Data System (ADS)

    Halim, A. A. A.; Laili, M. H.; Aziz, N. A.; Laili, A. R.; Salikin, M. S.; Rusop, M.

    2016-07-01

    The goal of this brief review is to report the techniques of functional near infrared spectroscopy for non-invasive evaluation in human study. The development of functional near infrared spectroscopy (fNIRS) technologies has advanced quantification signal using multiple wavelength and detector to solve the propagation of light inside the tissues including the absorption, scattering coefficient and to define the light penetration into tissues multilayers. There are a lot of studies that demonstrate signal from fNIRS which can be used to evaluate the changes of oxygenation level and measure the limitation of muscle performance in human brain and muscle tissues. Comprehensive reviews of diffuse reflectance based on beer lambert law theory were presented in this paper. The principle and development of fNIRS instrumentation is reported in detail.

  8. [Application of near infrared spectroscopy technique to nondestructive measurement of vegetable quality].

    PubMed

    Xie, Li-Juan; Ying, Yi-Bin; Yu, Hai-Yan; Fu, Xia-Ping

    2007-06-01

    Nondestructive detection techniques of vegetable include electrical properties, optical reflectance and transmission, sonic vibration, nuclear magnetic resonance (NMR), machine vision, aromatic volatile emission, vibration characteristics and others. The most widely employed and successful technique is to use its optical property. Near infrared spectroscopy technique is extremely fast, highly efficient, cheap to implement, of good recurrence and no sample preparation, and is a rapid and non-destructive modern measuring technique that has been widely used in many fields. In the present paper, the application of near infrared spectroscopy technique to nondestructive measurement of vegetable quality was briefly introduced. Some considerable aspects existing in the application were also discussed, and it is pointed out that because of vegetable's diversity and rot-proneness, automation analysis machine should be developed to improve the speed of quality detection, and cooperating with several other nondestructive techniques, such as NMR and machine vision, is the research trend.

  9. Instrumentation for Reflectance Spectroscopy and Microspectroscopy with Application to Astrobiology

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; Blaney, Diana L.; Green, Robert O.

    2008-01-01

    We present instrument concepts for in-situ reflectance spectroscopy over a spatial resolution range from several meters to tens of micrometers. These have been adapted to the low mass and power requirements of rover or similar platforms. Described are a miniaturized imaging spectrometer for rover mast, a combined mast and arm point spectrometer, and an imaging microspectrometer for the rover arm.

  10. Detection of Cracks on Tomatoes Using a Hyperspectral Near-Infrared Reflectance Imaging System

    PubMed Central

    Lee, Hoonsoo; Kim, Moon S.; Jeong, Danhee; Delwiche, Stephen R.; Chao, Kuanglin; Cho, Byoung-Kwan

    2014-01-01

    The objective of this study was to evaluate the use of hyperspectral near-infrared (NIR) reflectance imaging techniques for detecting cuticle cracks on tomatoes. A hyperspectral NIR reflectance imaging system that analyzed the spectral region of 1000–1700 nm was used to obtain hyperspectral reflectance images of 224 tomatoes: 112 with and 112 without cracks along the stem-scar region. The hyperspectral images were subjected to partial least square discriminant analysis (PLS-DA) to classify and detect cracks on the tomatoes. Two morphological features, roundness (R) and minimum-maximum distance (D), were calculated from the PLS-DA images to quantify the shape of the stem scar. Linear discriminant analysis (LDA) and a support vector machine (SVM) were then used to classify R and D. The results revealed 94.6% and 96.4% accuracy for classifications made using LDA and SVM, respectively, for tomatoes with and without crack defects. These data suggest that the hyperspectral near-infrared reflectance imaging system, in addition to traditional NIR spectroscopy-based methods, could potentially be used to detect crack defects on tomatoes and perform quality assessments. PMID:25310472

  11. High-resolution subtyping of Staphylococcus aureus strains by means of Fourier-transform infrared spectroscopy.

    PubMed

    Johler, Sophia; Stephan, Roger; Althaus, Denise; Ehling-Schulz, Monika; Grunert, Tom

    2016-05-01

    Staphylococcus aureus causes a variety of serious illnesses in humans and animals. Subtyping of S. aureus isolates plays a crucial role in epidemiological investigations. Metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy is commonly used to identify microbes at species as well as subspecies level. In this study, we aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. To this end, we compared the subtyping performance of FTIR spectroscopy to other subtyping methods such as pulsed field gel electrophoresis (PFGE) and spa typing in a blinded experimental setup and investigated the ability of FTIR spectroscopy for identifying S. aureus clonal complexes (CC). A total of 70 S. aureus strains from human, animal, and food sources were selected, for which clonal complexes and a unique virulence and resistance gene pattern had been determined by DNA microarray analysis. FTIR spectral analysis resulted in high discriminatory power similar as obtained by spa typing and PFGE. High directional concordance was found between FTIR spectroscopy based subtypes and capsular polysaccharide expression detected by FTIR spectroscopy and the cap specific locus, reflecting strain specific expression of capsular polysaccharides and/or other surface glycopolymers, such as wall teichoic acid, peptidoglycane, and lipoteichoic acid. Supervised chemometrics showed only limited possibilities for differentiation of S. aureus CC by FTIR spectroscopy with the exception of CC45 and CC705. In conclusion, FTIR spectroscopy represents a valuable tool for S. aureus subtyping, which complements current molecular and proteomic strain typing. PMID:27021524

  12. Testing the spectrum of infrared emission reflected by several surfaces with a FTIR

    NASA Astrophysics Data System (ADS)

    Wang, Xuanyu; Hu, Rui; Pang, Minhui; Bai, Haitao; Dong, Wenjie

    2014-09-01

    A set of sectional FTIR is applied to study the reflecting characteristics of several surfaces to infrared emission. The standard infrared source is separated from the host of the FTIR and set in a right-angled triangle with the reflecting plate and the entrance to make the reflecting infrared emission can easily pass into the detector through the route. The reflecting infrared emission from the FTIR source is measured by the FTIR detector. The reflecting plate includes metal plate, mirror, wood block and so on. A high intensity standard infrared source cooled by air is accepted and the testing background is atmosphere. The infrared emission reflected by the plate from the standard source is tested one by one. By the experiment, mirror has a good performance to reflect infrared emission, which is much better than unpainted iron plate or painted wood block. Certainly, unpainted iron plate has stronger capacity to reflect infrared emission than painted wood block, etc. As a result, the smoother the surface is, the stronger the reflecting performance is. The reflecting performance of painted surface to infrared emission is poorer than unpainted one. The various painted surfaces have not a visible difference upon their reflecting performance to infrared emission although they are made from different materials.

  13. Far-infrared synchrotron radiation spectroscopy of solids in normal and extreme conditions

    NASA Astrophysics Data System (ADS)

    Piccinini, M.; Cestelli Guidi, M.; Marcelli, A.; Calvani, P.; Burattini, E.; Nucara, A.; Postorino, P.; Sacchetti, A.; Arcangeletti, E.; Sheregii, E.; Polit, J.; Kisiel, A.

    2005-01-01

    New opportunities in solid-state physics are offered by SINBAD (Synchrotron INfrared Beamline At DAFNE), the infrared beamline operational at DANE, the storage ring of the Laboratori Nazionali di Frascati of the INFN. During 2003 several experiments, including those supported by the European TARI program, have been successfully performed at SINBAD. In this work we present the preliminary results of high resolution far infrared reflectivity data collected in different ZnxCdyHg(1-x-y)Te quaternary alloys as a function of temperature. The first far-IR investigation of Colossal Magnetoresistance manganites at high pressures, using a diamond anvil cell is also presented. Indeed, FT-IR spectroscopy is a powerful tool for the investigation of insulating-to-metal transitions and charge ordering phenomena that may occur in transition metal oxides.

  14. Terahertz reflection spectroscopy for the detection of explosives

    NASA Astrophysics Data System (ADS)

    Leahy-Hoppa, Megan R.; Fitch, Michael J.; Osiander, Robert

    2008-02-01

    Terahertz (THz) technology has been demonstrated as a promising tool for detection of explosives and is being developed for aviation screening and sensing of improvised explosive devices. THz radiation is attractive for many applications due to its ability to penetrate through a wide range of dielectric materials including clothing, paper, cardboard, plastics, and wood. Of course, metals block THz waves as is the case for microwave, IR, and visible light. Our work has involved investigating the reflection spectroscopy of a variety of materials including explosives such as RDX and PETN, plastic explosive taggants such as DMDNB, and other organic materials. We have also investigated the changes of the reflection spectra in varying grades of sucrose. Spectral differences are observed between three grades of crystalline sugar in the region from 0.1 to 1 THz. By exploiting the unique spectral features, the discrimination capabilities of THz reflection spectroscopy points to the broad applicability of identifying a wide variety of materials.

  15. Mid-IR fiber-optic reflectance spectroscopy for identifying the finish on wooden furniture.

    PubMed

    Poli, T; Chiantore, O; Nervo, M; Piccirillo, A

    2011-05-01

    Mid-IR fiber-optic reflectance spectroscopy (FORS) is a totally noninvasive infrared analytical technique allowing the investigation of artworks without the need for any sampling. The development and optimization of this analytical methodology can provide a tool that is capable of supporting conservators during the first steps of their interventions, yielding fast results and dramatically reducing the number of samples needed to identify the materials involved. Furthermore, since reflection IR spectra suffer from important spectral anomalies that complicate accurate spectral interpretation, it is important to characterize known reference materials and substrates in advance. This work aims to verify the possibility of investigating and identifying the most widely used wood finishes by means of fiber-optic (chalcogenide and metal halides) mid-infrared spectroscopy. Two historically widely employed wood finishes (beeswax, shellac) and two modern ones (a hydrogenated hydrocarbon resin and a microcrystalline wax) were investigated in an extended IR range (from 1000 to 6000 cm(-1)) with reflectance spectroscopy and with FORS. The broad spectral response of the MCT detector was exploited in order to include overtones and combination bands from the NIR spectral range in the investigation. The reflectance spectra were compared with those collected in transmission mode in order to highlight modifications to shapes and intensities, to assign absorptions, and finally to select "marker" bands indicating the presence of certain finishing materials, even when applied onto a substrate such as wood, which shows many absorptions in the mid-infrared region. After the characterization, the different products were applied to samples of aged pear wood and investigated with the same techniques in order to check the ability of mid-IR FORS to reveal the presence and composition of the product on the wooden substrate.

  16. Infrared Spectroscopy of Astrophysical Gas, Grains, and Ices with the Stratospheric Observatory for Infrared Astronomy (sofia)

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Becklin, E. E.

    2009-06-01

    The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) will be a premier facility for studying the physics and chemistry of the stellar evolution process for many decades. SOFIA spectroscopic science applications will be discussed, with special emphasis on investigations related to infrared spectroscopy of astrophysical gas, grains, and ices. Examples will be given of spectroscopic studies of the interstellar medium, protostars, obscured sources in molecular cloud cores, circumstellar disks around young stellar objects, remnants of nova and supernova explosions, and winds of evolved stellar systems.

  17. Infrared Spectroscopy of Noh Suspended in Solid Parahydrogen: Part Two

    NASA Astrophysics Data System (ADS)

    Balabanoff, Morgan E.; Mutunga, Fredrick M.; Anderson, David T.

    2015-06-01

    The only report in the literature on the infrared spectroscopy of the parent oxynitrene NOH was performed using Ar matrix isolation spectroscopy at 10 K. In this previous study, they performed detailed isotopic studies to make definitive vibrational assignments. NOH is predicted by high-level calculations to be in a triplet ground electronic state, but the Ar matrix isolation spectra cannot be used to verify this triplet assignment. In our 2013 preliminary report, we showed that 193 nm in situ photolysis of NO trapped in solid parahydrogen can also be used to prepare the NOH molecule. Over the ensuing two years we have been studying the infrared spectroscopy of this species in more detail. The spectra reveal that NOH can undergo hindered rotation in solid parahydrogen such that we can observe both a-type and b-type rovibrational transitions for the O-H stretch vibrational mode, but only a-type for the mode assigned to the bend. In addition, both observed a-type infrared absorption features (bend and OH stretch) display fine structure; an intense central peak with weaker peaks spaced symmetrically to both lower and higher wavenumbers. The spacing between the peaks is nearly identical for both vibrational modes. We now believe this fine structure is due to spin-rotation interactions and we will present a detailed analysis of this fine structure. Currently, we are performing additional experiments aimed at making 15NOH to test these preliminary assignments. The most recent data and up-to-date analysis will be presented in this talk. G. Maier, H. P. Reisenauer, M. De Marco, Angew. Chem. Int. Ed. 38, 108-110 (1999). U. Bozkaya, J. M. Turney, Y. Yamaguchi, and H. F. Schaefer III, J. Chem. Phys. 136, 164303 (2012). David T. Anderson and Mahmut Ruzi, 68th Ohio State University International Symposium on Molecular Spectroscopy, talk TE01 (2013).

  18. Noninvasive biochemical monitoring of physiological stress by Fourier transform infrared saliva spectroscopy.

    PubMed

    Khaustova, Svetlana; Shkurnikov, Maxim; Tonevitsky, Evgeny; Artyushenko, Viacheslav; Tonevitsky, Alexander

    2010-12-01

    Physical stress affects the immune system, activates the sympathetic (SNS) and parasympathetic (PNS) subsystems of autonomic nervous system (ANS), and increases the activity of the hypothalamic-pituitary-adrenal axis (HPA). The specific response of the major regulatory systems depends on the human functional state. Saliva is a unique diagnostic fluid, the composition of which immediately reflects the SNS, PNS, HPA and immune system response to stress. A new method of saliva biomarker determination by Attenuated Total Reflection Fourier-Transform Infrared (ATR FTIR) spectroscopy has been developed to monitor the exercise induced metabolic changes in saliva from male endurance athletes. The method has been tested using a group of professional athletes by analysing saliva samples collected before and after the exercise, and the saliva composition monitoring by ATR FTIR spectroscopy was shown to be suitable for real-time checking of response to stress.

  19. An infrared spectroscopy method to detect ammonia in gastric juice.

    PubMed

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M

    2015-11-01

    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations. PMID:26377936

  20. An infrared spectroscopy method to detect ammonia in gastric juice.

    PubMed

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M

    2015-11-01

    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

  1. Infrared polarization spectroscopy of CO 2 at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Alwahabi, Z. T.; Li, Z. S.; Zetterberg, J.; Aldén, M.

    2004-04-01

    Polarisation spectroscopy (PS) was used to probe CO 2 gas concentration in a CO 2/N 2 binary mixture at atmospheric pressure and ambient temperature. The CO 2 molecules were probed by a direct laser excitation to an overtone and combination vibrational state. The tuneable narrow linewidth infrared laser radiation at 2 μm was obtained by Raman shifting of the output from a single-longitudinal-mode pulsed alexandrite laser-system to the second Stokes component in a H 2 gas cell. Infrared polarisation spectroscopy (IRPS) and time-resolved infrared laser-induced fluorescence (IRLIF) spectra were collected. A linear dependence of the IRPS signal on the CO 2 mole fraction has been found. This indicates that the IRPS signal is only weakly affected by the molecular collisions and that the inter- and intra- molecular energy transfer processes do not strongly influence the molecular alignment at the time scale of the measurements. Thus IRPS holds great potential for quantitative instantaneous gas concentration diagnostics in general. This is especially important for molecules which do not posses an accessible optical transition such as CO, CO 2 and N 2O. In addition, an accurate experimental method to measure the extinction ratio of the IR polarisers employed in this study has been developed and applied. With its obvious merits as simplicity, easy alignment and high accuracy, the method can be generalized to all spectral regions, different polarisers and high extinction ratios.

  2. Composition of Polar Stratospheric Clouds from Infrared Spectroscopy

    NASA Technical Reports Server (NTRS)

    Tolbert, M. A.; Anthony, S. E.; Disselkamp, R.; Toon, O. B.; Condon, Estelle P. (Technical Monitor)

    1995-01-01

    Heterogeneous reactions on polar stratospheric clouds (PSCs) have recently been implicated in Arctic and Antarctic ozone destruction. Although the chemistry is well documented, the composition of the clouds remains uncertain. The most common PSCs (type I) are thought to be composed of HNO3/H2O mixtures. Although the exact process is not clear, type I PSCs are believed to nucleate on preexisting stratospheric sulfate aerosols (SSAs) composed of sulfuric acid and water. We are using infrared spectroscopy to study the composition and formation mechanism of type I PSCs. In the laboratory, we have used FTIR spectroscopy to probe the composition and phase of H2SO4/HNO3/H2O aerosols under winter polar stratospheric conditions. We have also used recently measured infrared optical constants for HNO3/H2O mixtures to analyze solar infrared extinction measurements of type I PSCs obtained in September 1987 over Antarctica. The results of these studies will be discussed in the context of current theories for polar stratospheric clouds formation.

  3. Pancreatic tissue assessment using fluorescence and reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Chandra, Malavika; Heidt, David; Simeone, Diane; McKenna, Barbara; Scheiman, James; Mycek, Mary-Ann

    2007-07-01

    The ability of multi-modal optical spectroscopy to detect signals from pancreatic tissue was demonstrated by studying human pancreatic cancer xenografts in mice and freshly excised human pancreatic tumor tissue. Measured optical spectra and fluorescence decays were correlated with tissue morphological and biochemical properties. The measured spectral features and decay times correlated well with expected pathological differences in normal, pancreatitis and adenocarcinoma tissue states. The observed differences between the fluorescence and reflectance properties of normal, pancreatitis and adenocarcinoma tissue indicate a possible application of multi-modal optical spectroscopy to differentiating between the three tissue classifications.

  4. Infrared and infrared emission spectroscopy of the zinc carbonate mineral smithsonite

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Martens, Wayde N.; Wain, Daria L.; Hales, Matt C.

    2008-10-01

    Infrared emission and infrared spectroscopy has been used to study a series of selected natural smithsonites from different origins. An intense broad infrared band at 1440 cm -1 is assigned to the ν CO 32- antisymmetric stretching vibration. An additional band is resolved at 1335 cm -1. An intense sharp Raman band at 1092 cm -1 is assigned to the CO 32- symmetric stretching vibration. Infrared emission spectra show a broad antisymmetric band at 1442 cm -1 shifting to lower wavenumbers with thermal treatment. A band observed at 870 cm -1 with a band of lesser intensity at 842 cm -1 shifts to higher wavenumbers upon thermal treatment and is observed at 865 cm -1 at 400 °C and is assigned to the CO 32-ν mode. No ν bending modes are observed in the Raman spectra for smithsonite. The band at 746 cm -1 shifts to 743 cm -1 at 400 °C and is attributed to the CO 32-ν in phase bending modes. Two infrared bands at 744 and around 729 cm -1 are assigned to the ν in phase bending mode. Multiple bands may be attributed to the structural distortion ZnO 6 octahedron. This structural distortion is brought about by the substitution of Zn by some other cation. A number of bands at 2499, 2597, 2858, 2954 and 2991 cm -1 in both the IE and infrared spectra are attributed to combination bands.

  5. Mid-Infrared Frequency-Agile Dual-Comb Spectroscopy

    NASA Astrophysics Data System (ADS)

    Luo, Pei-Ling; Yan, Ming; Iwakuni, Kana; Millot, Guy; Hänsch, Theodor W.; Picqué, Nathalie

    2016-06-01

    We demonstrate a new approach to mid-infrared dual-comb spectroscopy. It opens up new opportunities for accurate real-time spectroscopic diagnostics and it significantly simplifies the technique of dual-comb spectroscopy. Two mid-infrared frequency combs of slightly different repetition frequencies and moderate, but rapidly tunable, spectral span are generated in the 2800-3200 cm-1 region. The generators rely on electro-optic modulators, nonlinear fibers for spectral broadening and difference frequency generation and do not involve mode-locked lasers. Flat-top frequency combs span up to 10 cm-1 with a comb line spacing of 100 MHz (3×10-3 cm-1). The performance of the spectrometer without any phase-lock electronics or correction scheme is illustrated with spectra showing resolved comb lines and Doppler-limited spectra of methane. High precision on the spectroscopic parameter (line positions and intensities) determination is demonstrated for spectra measured on a millisecond time scale and it is validated with comparison with literature data. G. Millot, S. Pitois, M. Yan, T. Hovannysyan, A. Bendahmane, T.W. Hänsch, N. Picqué, Frequency-agile dual-comb spectroscopy, Nature Photonics 10, 27-30 (2016).

  6. Photoacoustic-based detector for infrared laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Scholz, L.; Palzer, S.

    2016-07-01

    In this contribution, we present an alternative detector technology for use in direct absorption spectroscopy setups. Instead of a semiconductor based detector, we use the photoacoustic effect to gauge the light intensity. To this end, the target gas species is hermetically sealed under excess pressure inside a miniature cell along with a MEMS microphone. Optical access to the cell is provided by a quartz window. The approach is particularly suitable for tunable diode laser spectroscopy in the mid-infrared range, where numerous molecules exhibit large absorption cross sections. Moreover, a frequency standard is integrated into the method since the number density and pressure inside the cell are constant. We demonstrate that the information extracted by our method is at least equivalent to that achieved using a semiconductor-based photon detector. As exemplary and highly relevant target gas, we have performed direct spectroscopy of methane at the R3-line of the 2v3 band at 6046.95 cm-1 using both detector technologies in parallel. The results may be transferred to other infrared-active transitions without loss of generality.

  7. Infrared Heterodyne Spectroscopy and its Unique Application to Planetary Studies

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodore

    2009-01-01

    Since the early 1970's the infrared heterodyne technique has evolved into a powerful tool for the study of molecular constituents, temperatures, and dynamics in planetary atmospheres. Its extremely high spectral resolution (Lambda/(Delta)Lambda/>10(exp 6)) and highly accurate frequency measurement (to 1 part in 10(exp 8)) enabled the detection of nonthermal/natural lasing phenomena on Mars and Venus; direct measurements of winds on Venus, Mars, and Titan; study of mid-infrared aurorae on Jupiter; direct measurement of species abundances on Mars (ozone, isotopic CO2), hydrocarbons on Jupiter, Saturn., Neptune, and Titan, and stratospheric composition in the Earth's stratosphere (O3, CIO, N2O, CO2 ....). Fully resolved emission and absorption line shapes measured by this method enabled the unambiguous retrieval of molecular abundances and local temperatures and thermal structure in regions not probed by other techniques. The mesosphere of Mars and thermosphere of Venus are uniquely probed by infrared heterodyne spectroscopy. Results of these studies tested and constrained photochemical and dynamical theoretical models describing the phenomena measured. The infrared heterodyne technique will be described. Highlights in its evolution to today's instrumentation and resultant discoveries will be presented, including work at Goddard Space Flight Center and the University of Koln. Resultant work will include studies supporting NASA and ESA space missions and collaborations between instrumental and theoretical groups.

  8. Determination of flow properties of pharmaceutical powders by near infrared spectroscopy.

    PubMed

    Sarraguça, Mafalda C; Cruz, Ana V; Soares, Sandra O; Amaral, Helena R; Costa, Paulo C; Lopes, João A

    2010-08-01

    The physical properties of pharmaceutical powders are of upmost importance in the pharmaceutical industry. The knowledge of their flow properties is of critical significance in operations such as blending, tablet compression, capsule filling, transportation, and in scale-up operations. Powders flow properties are measured using a number of parameters such as, angle of repose, compressibility index (Carr's index) and Hausner ratio. To estimate these properties, specific and expensive equipment with time-consuming analysis is required. Near infrared spectroscopy is a fast and low-cost analytical technique thoroughly used in the pharmaceutical industry in the quantification and qualification of products. To establish the potential of this technique to determine the parameters associated with the flow properties of pharmaceutical powders, blended powders based on paracetamol as the active pharmaceutical ingredient were constructed in pilot scale. Spectra were recorded on a Fourier-transform near infrared spectrometer in reflectance mode. The parameters studied were the angle of repose, aerated and tapped bulk density. The correlation between the reference method values and the near infrared spectrum was performed by partial least squares and optimized in terms of latent variables using cross-validation. The near infrared based properties predictions were compared with the reference methods results. Prediction errors, which varied between 2.35% for the angle of repose, 2.51% for the tapped density and 3.18% for the aerated density, show the potential of NIR spectroscopy in the determination of physical properties affecting the flowability of pharmaceutical powders.

  9. [Analysis of soil humus and components after 26 years' fertilization by infrared spectroscopy method].

    PubMed

    Zhang, Yu-Lan; Sun, Cai-Xia; Chen, Zhen-Hua; Li, Dong-Po; Liu, Xing-Bin; Chen, Li-Jun; Wu, Zhi-Jie; Du, Jian-Xiong

    2010-05-01

    The infrared spectrum was used to discuss structure change of soil humus and components of chemical groups in soil humic acids (HA) and fulvic acids (FA) isolated from soils in different fertilization treatment after 26 year's fertilization. The result indicated that using the infrared spectroscopy method for the determination of humus, humus fractions (HA and FA) and their structure is feasible. Fertilization affected the structure and content of soil humus and aromatization degree. After 26 years' fertilization, the infrared spectrum shapes with different treatments are similar, but the characteristic peak intensity is obviously different, which reflects the effects of different fertilization treatments on the structure and amounts of soil humus or functional groups. Compared with no fertilization, little molecule saccharides decreased and aryl-groups increased under application of inorganic fertilizer or combined application of organic and chemical fertilizer. The effect was greater in Treatment NPK and M+NPK than in Treatment M1 N and M2 N. Organic and NPK fertilizer increased the development of soil and increased soil quality to a certain extent. Results showed that organic fertilization increased aromatization degree of soil humus and humus fractions distinctly. The authors could estimate soil humus evolvement of different fertilization with infrared spectroscopy.

  10. Infrared Spectroscopy on Smoke Produced by Cauterization of Animal Tissue

    PubMed Central

    Gianella, Michele; Sigrist, Markus W.

    2010-01-01

    In view of in vivo surgical smoke studies a difference-frequency-generation (DFG) laser spectrometer (spectral range 2900–3144 cm−1) and a Fourier-transform infrared (FTIR) spectrometer were employed for infrared absorption spectroscopy. The chemical composition of smoke produced in vitro with an electroknife by cauterization of different animal tissues in different atmospheres was investigated. Average concentrations derived are: water vapor (0.87%), methane (20 ppm), ethane (4.8 ppm), ethene (17 ppm), carbon monoxide (190 ppm), nitric oxide (25 ppm), nitrous oxide (40 ppm), ethyne (50 ppm) and hydrogen cyanide (25 ppm). No correlation between smoke composition and the atmosphere or the kind of cauterized tissue was found. PMID:22319267

  11. Infrared Spectroscopy of Halogenated Species for Atmospheric Remote Sensing

    NASA Astrophysics Data System (ADS)

    Harrison, Jeremy J.

    2014-06-01

    Fluorine- and chlorine-containing molecules in the atmosphere are very strong greenhouse gases, meaning that even small amounts of these gases contribute significantly to the radiative forcing of climate. Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are regulated by the 1987 Montreal Protocol because they deplete the ozone layer. Hydrofluorocarbons (HFCs), which do not deplete the ozone layer and are not regulated by the Montreal Protocol, have been introduced as replacements for CFCs and HCFCs. HFCs have global-warming potentials many times greater than carbon dioxide, and are increasing in the atmosphere at a very fast rate. Various satellite instruments monitor many of these molecules by detecting infrared radiation that has passed through the Earth's atmosphere. However, the quantification of their atmospheric abundances crucially requires accurate quantitative infrared spectroscopy. This talk will focus on new and improved laboratory spectroscopic measurements for a number of important halogenated species.

  12. Cloud identification in atmospheric trace molecule spectroscopy infrared occultation measurements.

    PubMed

    Kahn, Brian H; Eldering, Annmarie; Irion, Fredrick W; Mills, Franklin P; Sen, Bhaswar; Gunson, Michael R

    2002-05-20

    High-resolution infrared nongas absorption spectra derived from the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment are analyzed for evidence of the presence of cirrus clouds. Several nonspherical ice extinction models based on realistic size distributions and crystal habits along with a stratospheric sulfate aerosol model are fit to the spectra, and comparisons are made with different model combinations. Nonspherical ice models often fit observed transmission spectra better than a spherical Mie ice model, and some discrimination among nonspherical models is noted. The ATMOS lines of sight for eight occultations are superimposed on coincident geostationary satellite infrared imagery, and brightness temperatures along the lines of sight are compared with retrieved vertical temperature profiles. With these comparisons, studies of two cases of clear sky, three cases of opaque cirrus, and three cases of patchy cirrus are discussed.

  13. Infrared and infrared emission spectroscopy of gallium oxide alpha-GaO(OH) nanostructures.

    PubMed

    Yang, Jing Jeanne; Zhao, Yanyan; Frost, Ray L

    2009-10-01

    Infrared spectroscopy has been used to study nano- to micro-sized gallium oxyhydroxide alpha-GaO(OH), prepared using a low temperature hydrothermal route. Rod-like alpha-GaO(OH) crystals with average length of approximately 2.5 microm and width of 1.5 microm were prepared when the initial molar ratio of Ga to OH was 1:3. beta-Ga(2)O(3) nano and micro-rods were prepared through the calcination of alpha-GaO(OH). The initial morphology of alpha-GaO(OH) is retained in the beta-Ga(2)O(3) nanorods. The combination of infrared and infrared emission spectroscopy complimented with dynamic thermal analysis were used to characterise the alpha-GaO(OH) nanotubes and the formation of beta-Ga(2)O(3) nanorods. Bands at around 2903 and 2836 cm(-1) are assigned to the -OH stretching vibration of alpha-GaO(OH) nanorods. Infrared bands at around 952 and 1026 cm(-1) are assigned to the Ga-OH deformation modes of alpha-GaO(OH). A significant number of bands are observed in the 620-725 cm(-1) region and are assigned to GaO stretching vibrations.

  14. Infrared and infrared emission spectroscopy of gallium oxide alpha-GaO(OH) nanostructures.

    PubMed

    Yang, Jing Jeanne; Zhao, Yanyan; Frost, Ray L

    2009-10-01

    Infrared spectroscopy has been used to study nano- to micro-sized gallium oxyhydroxide alpha-GaO(OH), prepared using a low temperature hydrothermal route. Rod-like alpha-GaO(OH) crystals with average length of approximately 2.5 microm and width of 1.5 microm were prepared when the initial molar ratio of Ga to OH was 1:3. beta-Ga(2)O(3) nano and micro-rods were prepared through the calcination of alpha-GaO(OH). The initial morphology of alpha-GaO(OH) is retained in the beta-Ga(2)O(3) nanorods. The combination of infrared and infrared emission spectroscopy complimented with dynamic thermal analysis were used to characterise the alpha-GaO(OH) nanotubes and the formation of beta-Ga(2)O(3) nanorods. Bands at around 2903 and 2836 cm(-1) are assigned to the -OH stretching vibration of alpha-GaO(OH) nanorods. Infrared bands at around 952 and 1026 cm(-1) are assigned to the Ga-OH deformation modes of alpha-GaO(OH). A significant number of bands are observed in the 620-725 cm(-1) region and are assigned to GaO stretching vibrations. PMID:19577510

  15. In-situ ultra-sensitive infrared absorption spectroscopy of biomolecule interactions in real time with plasmonic nanoantennas

    PubMed Central

    Adato, Ronen; Altug, Hatice

    2013-01-01

    Infrared absorption spectroscopy is a powerful biochemical analysis tool as it extracts detailed molecular structural information in a label-free fashion. Its molecular specificity renders the technique sensitive to the subtle conformational changes exhibited by proteins in response to a variety of stimuli. Yet, sensitivity limitations and the extremely strong absorption bands of liquid water severely limit infrared spectroscopy in performing kinetic measurements in biomolecules’ native, aqueous environments. Here we demonstrate a plasmonic chip-based technology that overcomes these challenges, enabling the in-situ monitoring of protein and nanoparticle interactions at high sensitivity in real time, even allowing the observation of minute volumes of water displacement during binding events. Our approach leverages the plasmonic enhancement of absorption bands in conjunction with a non-classical form of internal reflection. These features not only expand the reach of infrared spectroscopy to a new class of biological interactions but also additionally enable a unique chip-based technology. PMID:23877168

  16. Chemometric analysis of attenuated total reflectance infrared spectra of Proteus mirabilis strains with defined structures of LPS.

    PubMed

    Zarnowiec, Paulina; Mizera, Andrzej; Chrapek, Magdalena; Urbaniak, Mariusz; Kaca, Wieslaw

    2016-07-01

    Proteus spp. strains are some of the most important pathogens associated with complicated urinary tract infections and bacteremia affecting patients with immunodeficiency and long-term urinary catheterization. For epidemiological purposes, various molecular typing methods have been developed for this pathogen. However, these methods are labor intensive and time consuming. We evaluated a new method of differentiation between strains. A collection of Proteus spp. strains was analyzed by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy in the mid-infrared region. ATR FT-IR spectroscopy used in conjunction with a diamond ATR accessory directly produced the biochemical profile of the surface chemistry of bacteria. We conclude that a combination of ATR FT-IR spectroscopy and mathematical modeling provides a fast and reliable alternative for discrimination between Proteus isolates, contributing to epidemiological research. PMID:27189426

  17. Depth-resolved measurements with elliptically polarized reflectance spectroscopy

    PubMed Central

    Bailey, Maria J.; Sokolov, Konstantin

    2016-01-01

    The ability of elliptical polarized reflectance spectroscopy (EPRS) to detect spectroscopic alterations in tissue mimicking phantoms and in biological tissue in situ is demonstrated. It is shown that there is a linear relationship between light penetration depth and ellipticity. This dependence is used to demonstrate the feasibility of a depth-resolved spectroscopic imaging using EPRS. The advantages and drawbacks of EPRS in evaluation of biological tissue are analyzed and discussed. PMID:27446712

  18. Transient Two-Dimensional Infrared Spectroscopy in a Vibrational Ladder.

    PubMed

    Kemlin, Vincent; Bonvalet, Adeline; Daniault, Louis; Joffre, Manuel

    2016-09-01

    We report on transient 2D Fourier transform infrared spectroscopy (2DIR) after vibrational ladder climbing induced in the CO-moiety longitudinal stretch of carboxyhemoglobin. The population distribution, spreading up to seven vibrational levels, results in a nonequilibrium 2DIR spectrum evidencing a large number of peaks that can be easily attributed to individual transitions thanks to the anharmonicity of the vibrational potential. We discuss the physical origin of the observed peaks as well as the qualitative behavior of the subsequent dynamics governed by population relaxation in the vibrational ladder. PMID:27508408

  19. Innovative uses of near-infrared spectroscopy in food processing.

    PubMed

    Bock, J E; Connelly, R K

    2008-09-01

    Near-infrared spectroscopy (NIRS) has experienced widespread use as an analytical tool in the last 3 decades. Researchers today are exploring ways of applying NIRS that expand beyond compositional analyses into process control. Processes such as meat tenderness evaluation, curd cutting, and dough mixing have traditionally been controlled by highly skilled master craftsmen; new NIRS research applications are demonstrating that these complex processes can be monitored and controlled in situ to produce consistent, high quality end products with online NIRS technology. Additionally, researchers also now have the potential ability to develop new nondestructive spectroscopic techniques to probe the underlying molecular evolution of these products during processing.

  20. Note: wearable near-infrared spectroscopy imager for haired region.

    PubMed

    Kiguchi, M; Atsumori, H; Fukasaku, I; Kumagai, Y; Funane, T; Maki, A; Kasai, Y; Ninomiya, A

    2012-05-01

    A wearable optical topography system was developed that is based on near-infrared spectroscopy (NIRS) for observing brain activity noninvasively including in regions covered by hair. An avalanche photo diode, high voltage dc-dc converter, and preamplifier were placed in an electrically shielded case to be safely mounted on the head. Rubber teeth and a glass rod were prepared to clear away hair and reach the scalp. These devices realized for the first time a wearable NIRS imager for any region of the cortex. The activity in the motor cortex during finger tapping was successfully observed.