Journal articles: 'FT-IR spectra'

1

Varlashkin, P. G., M. J. D. Low, G. A. Parodi, and C. Morterra. "A Comparison of FT-IR/PA and FT-IR/PBD Spectra of Powders." Applied Spectroscopy 40, no. 5 (July 1986): 636–41. http://dx.doi.org/10.1366/0003702864508539.

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FT-IR photoacoustic (PA) and also photothermal beam deflection (PBD) spectra were recorded with the same particulate samples (graphite, charcoal, aspirin, and silica) under the same conditions in order to compare the quality of the spectra obtainable with the two techniques. A PA cell fitted with windows for the PBD laser probe beam was used, and PA and PBD spectra of each sample were recorded at 8 cm−1 resolution at each of the four different interferometer scan velocities. Although the overall aspects of FT-IR/PA and FT-IR/PBD spectra are the same, the signal-to-noise ratios of PA spectra are appreciably better than those of PBD spectra because PBD detection is more prone to disturbance by vibration than is PA detection. Absorption bands appear at the same wavenumbers in PA and PBD spectra. However, the relative intensities of bands of PBD spectra depend on the absorptive properties of the powdered solids; with weak absorbers, some bands may not be detected at all. PAS can be used with all powders. PBDS is of little or no use for the examination of weakly absorbing powders unless they scatter IR radiation extensively.

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Marcott, Curtis, A. E. Dowrey, and Isao Noda. "Instrumental Aspects of Dynamic Two-Dimensional Infrared Spectroscopy." Applied Spectroscopy 47, no. 9 (September 1993): 1324–28. http://dx.doi.org/10.1366/0003702934067531.

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Dynamic two-dimensional infrared (2D IR) correlation maps are a convenient means of examining the information contained in time-resolved IR spectra. Dynamic 2D IR spectra can be collected with the use of either dispersive or Fourier transform (FT) IR spectrometers. Use of a step-scanning FT-IR spectrometer has advantages over conventional rapid-scan FT-IR spectrometry when one is acquiring time-resolved IR data on time scales faster than about 0.1 s, because the spectral multiplexing is removed from the time domain. Dynamic IR spectra of atactic polystyrene (undergoing a small-amplitude oscillatory strain) collected on both dispersive and FT instrumentation are compared. Although the dispersive approach produces higher signal-to-noise ratios over small spectral regions, the multiplex advantage makes the FT approach attractive when broader spectral coverages are required. The first vibrational circular dichroism (VCD) spectrum [of (–)- α;-pinene] collected on a step-scanning interferometer is also presented.

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Petibois, Cyril, Georges Cazorla, André Cassaigne, and Gérard Déléris. "Plasma Protein Contents Determined by Fourier-Transform Infrared Spectrometry." Clinical Chemistry 47, no. 4 (April 1, 2001): 730–38. http://dx.doi.org/10.1093/clinchem/47.4.730.

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Abstract Background: Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins. Methods: We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption of the biomolecule at the most characteristic spectral range was calculated by analyzing pure samples of known concentrations. (c) The plasma concentration of the biomolecule was determined using the FT-IR absorption of the pure compound and the integration value obtained for the plasma FT-IR spectra. (d) The spectral contribution of the biomolecule was subtracted from the plasma FT-IR spectra, and the resulting spectra were saved for further analyses. (e) The same method was then applied to determining the concentrations of other biomolecules by sequentially comparing the resulting FT-IR spectra. Results: Results agreed with those obtained by clinical methods for the following biomolecules when analyzed in the following order: albumin, glucose, fibrinogen, IgG2, lactate, IgG1, α1-antitrypsin, α2-macroglobulin, transferrin, apolipoprotein (Apo)-A1, urea, Apo-B, IgM, Apo-C3, IgA, IgG4, IgG3, IgD, haptoglobin, and α1-acid glycoprotein. Conclusion: FT-IR spectrometry is a useful tool for determining concentrations of several plasma biomolecules.

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Filip, Z., S. Hermann, and K. Demnerová. "FT-IR spectroscopic characteristics of differently cultivated Escherichia coli." Czech Journal of Food Sciences 26, No. 6 (January 11, 2009): 458–63. http://dx.doi.org/10.17221/14/2008-cjfs.

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FT-IR spectra were recorded of <i>Escherichia coli</i> cell mass with the aim of obtaining spectral traits possibly useful in a rapid detection and characterisation of this indicator bacterium. A well differentiated spectrum was obtained from the cell mass harvested in a stationary phase of growth, e.g., after 24 h, from a minimum nutrient broth. The cell mass, harvested either earlier or grown in nutrient solutions which contained an enhanced carbon or nitrogen concentrations delivered somewhat different IR spectra, apparently due to a higher content of nucleic acid components as related to other structural constituents of bacterial cells. Consequently, the FT-IR spectra of <i>E. coli</i>, although rather rapidly to collect, seem only capable of delivering useful and reproducible information if the cell mass is obtained under standardised cultural conditions.

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Lasch, Peter, Wolfgang Haensch, E. Neil Lewis, Linda H. Kidder, and Dieter Naumann. "Characterization of Colorectal Adenocarcinoma Sections by Spatially Resolved FT-IR Microspectroscopy." Applied Spectroscopy 56, no. 1 (January 2002): 1–9. http://dx.doi.org/10.1366/0003702021954322.

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A combination of Fourier transform infrared (FT-IR) spectroscopy and microscopy, FT-IR microspectroscopy, has been used to characterize sections of human colorectal adenocarcinoma. In this report, a database of 2601 high quality FT-IR point spectra from 26 patient samples and seven different histological structures was recorded and analyzed. The computer-based analysis of the IR spectra was carried out in four steps: (1) an initial test for spectral quality, (2) data pre-processing, (3) data reduction and feature selection, and (4) classification of the tissue spectra by multivariate pattern recognition techniques such as hierarchical clustering and artificial neural network analysis. Furthermore, an example of how spectral databases can be utilized to reassemble false color images of tissue samples is presented. The overall classification accuracy attained by optimized artificial neural networks reached 95%, highlighting the great potential of FT-IR microspectroscopy as a potentially valuable, reagent-free technique for the characterization of tissue specimens. However, technical improvements and the compilation of validated spectral databases are essential prerequisites to make the infrared technique applicable to routine and experimental clinical analysis.

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Saarinen, Pekka, and Jyrki Kauppinen. "Multicomponent Analysis of FT-IR Spectra." Applied Spectroscopy 45, no. 6 (July 1991): 953–63. http://dx.doi.org/10.1366/0003702914336309.

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Taga, Keijiro, Michael G. Sowa, Jing Wang, Hideki Etori, Tadayoshi Yoshida, Hirofumi Okabayashi, and Henry H. Mantsch. "FT-IR spectra of glycine oligomers." Vibrational Spectroscopy 14, no. 1 (March 1997): 143–46. http://dx.doi.org/10.1016/s0924-2031(96)00061-6.

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D’Anna, Vincenza, Alexandra Spyratou, Manish Sharma, and Hans Hagemann. "FT-IR spectra of inorganic borohydrides." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (July 2014): 902–6. http://dx.doi.org/10.1016/j.saa.2014.02.130.

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9

Bellamy, M. K., A. N. Mortensen, R. M. Hammaker, and W. G. Fateley. "Chemical Mapping in the Mid- and Near-IR Spectral Regions by Hadamard Transform/FT-IR Spectrometry." Applied Spectroscopy 51, no. 4 (April 1997): 477–86. http://dx.doi.org/10.1366/0003702971940747.

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A movable two-dimensional (2D) Hadamard encoding mask is obtained and combined with conventional FT-IR spectrometers for use in both the mid- and near-infrared spectral regions. Chemical maps and spectra of individual pixels of the maps can be obtained from heterogeneous samples by using this combination of a move-able 2D Hadamard encoding mask and an FT-IR spectrometer. We call the procedure Hadamard transform/FT-IR spectrometry. Spectra of usable signal-to-noise ratio and reliable chemical maps are obtained in reasonable data acquisition and processing time.

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Norton, Kelly L., Andrew M. Haefner, Hideo Makishima, George Jalsovszky, and Peter R. Griffiths. "Comparison of Direct-Deposition Supercritical Fluid and Gas Chromatography/Fourier Transform Infrared Spectra to Condensed-Phase Library Spectra." Applied Spectroscopy 50, no. 9 (September 1996): 1125–33. http://dx.doi.org/10.1366/0003702963905051.

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Comparisons of spectra from direct-deposition (DD) capillary gas chromatography (GC) and supercritical fluid chromatography (SFC)/Fourier transform infrared (FT-IR) measurements of two quinones with C2 symmetry axes and several barbiturates to spectra from condensed-phase libraries of the corresponding compounds are reported. The best spectral search results were obtained when the eluites were deposited on an amorphous substrate, such as ZnSe. A small number of polar, hydrogen-bonding compounds were found to align with each other or with a crystalline substrate. Different crystalline forms of some polymorphic analytes can also yield ambiguous identifications. These effects produce enough differences in the DD GC/FT-IR and SFC/FT-IR spectra to cause occasional incorrect identifications when the spectra are searched against KBr-disk library spectra.

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Sepman, A. V., R. den Blanken, R. Schepers, and L. P. H. de Goey. "Quantitative Fourier Transform Infrared Diagnostics of the Gas-Phase Composition Using the HITRAN Database and the Equivalent Width of the Spectral Features." Applied Spectroscopy 63, no. 11 (November 2009): 1211–22. http://dx.doi.org/10.1366/000370209789806948.

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This paper presents a strategy for quantification of medium resolution Fourier transform infrared (FT-IR) spectra. The approach is based on a comparison of the values of the equivalent width of spectral features determined from the measured FT-IR spectra with those calculated from corresponding molecular spectra simulated using spectroscopic parameters tabulated in the HITRAN database. Although the equivalent-width method is routinely applied in many high-resolution experiments, its potential is often ignored when the spectral resolution of the measurements is bigger than the width of the studied molecular transitions. Here with an eye on application of the method to the study of the biomass thermal decomposition products, we demonstrate the capability of the method for analysis of FT-IR spectra with moderate resolution. The method is validated for a number of molecules (NH3, CO, CH4, C2H2, C2H4, and NO) that are important products of biomass thermal decomposition. Namely, known amounts of gases were placed in a sample cell and their concentrations were determined using the method for different FT-IR settings. The agreement between the concentration values determined using the present method and those found in the sample cell was generally better than 10%. The paper also shows examples of application of the developed methodology for the analysis of FT-IR spectra from biomass pyrolysis.

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12

Robertson, R. M., J. A. de Haseth, and R. F. Browner. "MAGIC-LC/FT-IR Spectrometry with Buffered Solvent Systems." Applied Spectroscopy 44, no. 1 (January 1990): 8–13. http://dx.doi.org/10.1366/0003702904085886.

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The first demonstration of identifiable infrared (IR) spectra obtained from buffered (volatile and nonvolatile buffers) mobile phases using the Monodisperse Aerosol Generator Interface for Combining Liquid Chromatography with Fourier Transform Infrared (MAGIC-LC/FT-IR) spectrometry is described. Ammonium acetate, a volatile buffer, was used to buffer an 80:20 acetonitrile: water mobile phase to pH 5.0. Caffeine was deposited from this buffered mobile phase, and the spectrum was used as a reference to compare with caffeine spectra obtained from nonvolatile buffered mobile phases. The two nonvolatile buffers used were potassium hydrogen phthalate (KHP) and potassium dihydrogen phosphate (KH2PO4). The KH2PO4 was used to buffer an acetonitrile:water mobile phase and a methanol:water mobile phase, whereas the KHP buffer was used only in a methanoh:water mobile phase. Samples of caffeine were deposited from each of the above buffer systems along with the nonvolatile buffer. Infrared spectra of caffeine were obtained by spectral subtraction of previously stored buffer spectra from the caffeine:buffer spectra. The resulting spectra were identical to a caffeine reference spectrum.

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13

Reffner, John A., and William T. Wihlborg. "Microanalysis of Asbestos Fibers by Ft-IR Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 298–99. http://dx.doi.org/10.1017/s0424820100135095.

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The identification of asbestos fibers in bulk or airborne samples can be made by Fourier transform infrared (FT-IR) microscopy. Since asbestos fibers have been shown to be a health hazard, it is important to identify their presence in environmental samples. Asbestos fibers require both chemical and morphological data for their identification. This FT-IR microscopical method uses light microscopy for morphological and infrared spectroscopy for chemical identity of microscopic fibers. For the six minerals defined by the EPA as asbestos, the infrared spectral analysis can be made on the same sample preparations that are used for polarized light microscopy(PLM) or phase contrast microscopy (PCM) counting. In this study, the detection limit for asbestos fibers in airborne samples was 2 × 20μm (˜˜240pg).The infrared spectra of microscopic fiber bundles of standard asbestos minerals were obtained using an IRμS™ infrared microspectrometer. Spectra were collected within the range of 4000 to 600 cm-1 (2.4 to 16.7 μm), at a spectral resolution of either 2 or 4 cm-1.

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Álvarez, Ángela, and Jorge Yáñez. "Screening of Gunshot Residue in Skin Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Hyperspectral Microscopy." Applied Spectroscopy 74, no. 4 (January 28, 2020): 400–407. http://dx.doi.org/10.1177/0003702819892930.

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The detection of gunshot residues (GSR) in skin is important in criminal forensic investigations related with firearms. Conventionally, the procedure is based on the detection of metallic or inorganic residues (IGSR). In this work, we propose attenuated total reflectance Fourier transform infrared (ATR FT-IR) hyperspectral microscopy as a complementary and nondestructive technique for detection of organic GSR (OGSR). The spectra were acquired from GSR of three ammunition manufacturers, which were collected from shooter’s hands by the tape-lifting method. Before spectroscopic analysis, a Na–Ca bleach solution was added to all GSR samples on the tape for destroying skin debris. Positive detection of OGSR spectra were achieved by ATR FT-IR hyperspectral microscopy. Spectra show characteristic patterns of nitrate ester compounds which agrees with the propellant chemical composition. Characteristic ATR FT-IR spectral patterns of OGSR were measured from visualized GSR particles demonstrating the potential of ATR FT-IR hyperspectral microscopy.

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Hutson, M. Shane, and Mark S. Braiman. "Direct Phase Correction of Differential FT-IR Spectra." Applied Spectroscopy 52, no. 7 (July 1998): 974–84. http://dx.doi.org/10.1366/0003702981944616.

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Step-scan transient Fourier transform infrared (FT-IR) difference spectra are often measured in an ac-coupled configuration. The resulting differential intensity spectra contain both positive and negative bands. This condition poses problems for direct phase correction by the standard Mertz and Forman methods. Restricting the calculated phase angle to the range [–π/2, π/2] was previously shown to fix some of these problems, but we show that the use of a reduced-resolution phase spectrum can produce other artifacts. The effect of reduced resolution is analyzed for a simulated noise-free spectrum and for a measured transient spectrum of a real photochemical system, bacteriorhodopsin. Examination of these results reveals that the Mertz and Mertz Signed methods can produce spectral bands of reduced magnitude and unusual band shape, with considerable amounts of intensity remaining along the imaginary axis after phase correction. However, these errors can be eliminated by self-convolution of the measured interferogram, which doubles all phase angles, prior to smoothing. This procedure removes the potential discontinuities in the phase angle due to sign changes in the differential spectrum. With bacteriorhodopsin, this doubled-angle method for direct phase correction is able to produce a transient spectrum which closely matches that produced by using a separately measured dc interferogram to calculate the phase angle.

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Yohannan Panicker, C., Hema Tresa Varghese, and Daizy Philip. "FT-IR, FT-Raman and SERS spectra of Vitamin C." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 65, no. 3-4 (November 2006): 802–4. http://dx.doi.org/10.1016/j.saa.2005.12.044.

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Mary, Y. Sheena, L. Ushakumari, B. Harikumar, H. Tresa Varghese, and C. Yohannan Panicker. "FT-IR, FT-raman and SERS spectra of L-proline." Journal of the Iranian Chemical Society 6, no. 1 (March 2009): 138–44. http://dx.doi.org/10.1007/bf03246512.

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Anto, P. L., R. J. Anto, H. T. Varghese, C. Y. Panicker, D. Philip, and A. G. Brolo. "FT-IR, FT-Raman and SERS spectra of anilinium sulfate." Journal of Raman Spectroscopy 40, no. 12 (June 1, 2009): 1810–15. http://dx.doi.org/10.1002/jrs.2323.

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Webb, J. D., D. J. Dunlavy, T. Ciszek, R. K. Ahrenkiel, M. W. Wanlass, R. Noufi, and S. M. Vernon. "Room-Temperature Measurement of Photoluminescence Spectra of Semiconductors Using an FT-Raman Spectrophotometer." Applied Spectroscopy 47, no. 11 (November 1993): 1814–19. http://dx.doi.org/10.1366/0003702934066019.

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This paper demonstrates the utility of an FT-Raman accessory for an FT-IR spectrophotometer in obtaining the room-temperature photoluminescence (PL) spectra of semiconductors used in photovoltaic and electro-optical devices. Sample types analyzed by FT-IR/PL spectroscopy included bulk silicon and films of gallium indium arsenide phosphide (GaInAsP), copper indium diselenide (CuInSe2), and gallium arsenide-germanium alloy on various substrates. The FT-IR/PL technique exhibits advantages in speed, sensitivity, and freedom from stray light over conventional dispersive methods, and can be used in some cases to characterize complete semiconductor devices as well as component materials at room temperature. Some suggestions for improving the spectral range of the technique and removing instrumental spectral artifacts are presented.

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Fleyfel, Fouad, and J. Paul Devlin. "FT-IR spectra of carbon dioxide clusters." Journal of Physical Chemistry 93, no. 21 (October 1989): 7292–94. http://dx.doi.org/10.1021/j100358a005.

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Maharaj, V., D. Tsankov, H. J. van de Sande, and H. Wieser. "FT IR-VCD spectra of six octadeoxynucleotides." Journal of Molecular Structure 349 (April 1995): 25–28. http://dx.doi.org/10.1016/0022-2860(95)08700-6.

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Baran, J., M. Wierzejewska-Hnat, E. T. G. Lutz, and J. H. Van Der Maas. "Polarized FT—IR spectra of adamantanol derivatives." Journal of Molecular Structure 244 (April 1991): 87–101. http://dx.doi.org/10.1016/0022-2860(91)80150-3.

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23

Huang, J. B., and M. W. Urban. "Effect of Overlapping Bands on Intensities in ATR FT-IR Spectra." Applied Spectroscopy 46, no. 6 (June 1992): 1014–19. http://dx.doi.org/10.1366/0003702924124466.

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In this study, several spectra were simulated, and the effect of spectral resolution and intensity is compared for ATR and transmission measurements. The analysis of ATR spectra shows that the intensity differences become more pronounced with the increasing band intensities and decreasing separation of the bands. The intensity ratio differences in ATR spectra are due to the superposition of the asymmetric dispersion bands of the refractive index spectrum. The difference between the spectral features in an overlapping region in ATR and transmission measurements is illustrated, and it is shown that the optical dispersion effect can be effectively eliminated by converting an ATR spectrum into its absorbance counterpart with the use of the Kramers-Kronig transform.

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Friese, Michael A., and Sujit Banerjee. "Lignin Determination by FT-IR." Applied Spectroscopy 46, no. 2 (February 1992): 246–48. http://dx.doi.org/10.1366/0003702924125456.

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The lignin content of pulp is determined from its diffuse reflectance infrared spectrum by an algorithm that calculates the degree of overlap between two spectra. The lignin:cellulose fraction correlates with kappa number, a titrimetric measure of lignin. Essentially no sample preparation is required, and the procedure is insensitive to variations in moisture content. The algorithm is able to detect changes induced by exposure of pulp to NO2.

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Zhu, Ziang, Wayne Parker, and Alexander Wong. "PlasticNet: Deep Learning for Automatic Microplastic Recognition via FT-IR Spectroscopy." Journal of Computational Vision and Imaging Systems 6, no. 1 (January 15, 2021): 1–3. http://dx.doi.org/10.15353/jcvis.v6i1.3554.

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The recognition of microplastics (MPs) in environmental samples via FT-IR is challenging due to a plethora of factors can lead to significant variances in measured spectra. Conventional library search approaches compare the observed spectrum with spectra in reference libraries, which will lead to errors due the variance in spectra. Motivated to tackle this challenge, this study explores the feasibility of leveraging deep learning for automatic MP recognition via FT-IR spectroscopy. More specifically, a deep convolution neural network (CNN) architecture, referred to here as PlasticNet, is introduced for the purpose of automatic MP recognition. PlasticNet was trained on a large corpus of FT-IR spectra of different plastic types in order to learn discriminative spectral features characterizing each plastic type. Experimental results showed that PlasticNet was capable of recognizing between MPs in an effective way and at a faster speed compared with libary search.

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Govindarajan, M., S. Periandy, and K. Ganesan. "Scaled Quantum FT-IR and FT-Raman Spectral Analysis of 1-Methoxynaphthalene." E-Journal of Chemistry 7, no. 2 (2010): 457–64. http://dx.doi.org/10.1155/2010/702587.

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The structural and vibrational property of 1-methoxynaphthalene has been studied. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using B3LYP/6-31G (d, p) basis set and was scaled using various scale factors, which yielded a good agreement between observed and calculated frequencies. The vibrational spectra were interpreted with the aid of normal coordinate analysis. The results of the calculations were applied to simulated spectra of the title compound, which shows excellent agreement with observed spectra. The calculated force constants in vibrational internal coordinates are in closely coincides with the experimentally observed force constants.

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Sullivan, David H., W. Curtis Conner, and Michael P. Harold. "Surface Analysis with FT-IR Emission Spectroscopy." Applied Spectroscopy 46, no. 5 (May 1992): 811–18. http://dx.doi.org/10.1366/0003702924124844.

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The technique of infrared emission spectroscopy (IRES) is reviewed and further examined in this study as a surface analysis tool. A system has been designed which allows simultaneous kinetic and in situ infrared emission analysis of catalyst surfaces. IRES spectra of several gas mixture/solid systems are obtained in order to examine sample preparation and spectra processing issues; these systems include Pt/Al2O3 exposed to CO and CO-NO mixtures, an oxidized copper plate, and a zeolite exposed to inert atmospheres. For the temperature range of importance to catalysis (300–600 K), IRES is limited to frequencies less than 2500 cm−1. However, IRES is especially well suited for studying solid-state vibrational modes (<1000 cm−1). Moreover, IRES allows catalyst samples to be studied without dilution or extensive sample preparation. The thin samples required for IRES make it possible to study both surface adsorbate and the solid-state lattice vibrations simultaneously. This information can provide useful insight into the interpretation of kinetic data of reactions on metal oxide catalysts. However, samples which are too thick or are supported on a high-emissivity surface will not yield satisfactory spectra. Two correction techniques are examined which reduce background and sample-reflectance effects in the emission spectra. Some of the IRES data are compared to the corresponding spectra obtained by transmission and diffuse-reflectance spectroscopy. IRES is shown to be competitive with these more popular techniques for IR surface analysis.

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Coleman, W. M., Bert M. Gordon, and Brian M. Lawrence. "Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XII." Applied Spectroscopy 43, no. 2 (February 1989): 298–304. http://dx.doi.org/10.1366/0003702894203273.

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Matrix isolation Fourier transform infrared spectra (MI/FT-IR), mass spectra (MS), carbon-13 Nuclear Magnetic Resonance (13C-NMR) spectra, condensed-phase infrared spectra, and vapor-phase infrared (IR) spectra are presented for a series of terpene compounds. Subtle differences in positional and configurational isomers commonly found with terpenes could be easily detected by the MI/FT-IR spectra. The results are comparable in some aspects to those obtainable from 13C-NMR and thin-film IR; however, most importantly, they are acquired at the low nanogram level for MI/FT-IR, as compared to the milligram level for the other techniques. These results represent an advance in the technology available for the analysis of complex mixtures such as essential oils containing terpene-like molecules.

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Robertson, R. M., J. A. De Haseth, J. D. Kirk, and R. F. Browner. "MAGIC-LC/FT-IR Spectrometry: Preliminary Studies." Applied Spectroscopy 42, no. 8 (November 1988): 1365–68. http://dx.doi.org/10.1366/0003702884429634.

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A new solvent elimination interface based on the Monodisperse Aerosol Generation Interface for Combining Liquid Chromatography with Fourier transform infrared (MAGIC-LC/FT-IR) spectrometry is described. The solvent elimination efficiency of MAGIC-LC/FT-IR was studied by varying the mobile-phase composition from 100% methanol to 100% water. As the mobile-phase composition was varied, erythrosin B was injected into the interface and deposited on a KBr window after the solvent removal. Spectra were obtained which compared favorably with reference spectra, even as the mobile-phase water content was increased. A reverse-phase separation was completed to demonstrate that readily identifiable spectra can be obtained from mobile phases containing high percentages of water, without heating of the effluent stream.

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Yaniger, Stuart I., and D. Warren Vidrine. "Dynamic FT-IR. Part I: Rapid-Scan Methods in Spectroelectrochemistry." Applied Spectroscopy 40, no. 2 (February 1986): 174–80. http://dx.doi.org/10.1366/0003702864509394.

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Current rapid-scan FT-IR instrumentation allows medium resolution (16 cm−1) infrared spectra to be acquired and separately stored at a rate of 85 spectra per second with excellent signal-to-noise ratio. This corresponds to a time resolution of about 12 ms. Higher spectral resolutions are possible at a cost of some spectrometer speed. Rapid-scan FT-IR provides a means by which the course of electrochemical reactions can be followed and, unlike digital time-resolved and double-modulation FT-IR, this method is not limited to reversible reactions and may be used with impunity by the nonspecialist. We examine several examples of irreversible electrochemical processes including solution-phase redox chemistry, electropolymerizations, and doping reactions of conducting polymers.

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Petibois, Cyril, and Gérard Déléris. "Stress-Induced Plasma Volume Change Determined Using Plasma FT-IR Spectra." Applied Spectroscopy 57, no. 4 (April 2003): 396–99. http://dx.doi.org/10.1366/00037020360625925.

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Our purpose was to determine the plasma-volume (PV) change induced by a physical stress independent of the metabolic events that may interfere with physiological fluid shifts in to and out of the intravascular space. Our methods included using 178 exercise tests of varying duration and intensity for determination of PV change during exercise. Plasma Fourier transform infrared (FT-IR) spectra were used to compare hematocrit change to the total spectral area (4000–500 cm−1) and the protein and albumin concentration changes induced by exercise. Our results showed that exercise induced a raise in protein (+10.4 ± 3.1%) and albumin (+9.8 ± 3.3%) concentrations that significantly correlated with PV change (14.1 ± 5.2% of plasma volume; P = 0.05 with protein and albumin concentration changes). However, evolution of the total spectral area obtained from rest-plasma (524 ± 21 a.u.) and exercise-plasma (611 ± 26 a.u.; +14.1 ± 4.8%) FT-IR spectra showed a higher correlation level with PV change ( r = 0.98; P = 0.005; Sx/y = 1.26 a.u.). It is our conclusion that although exercise-induced changes in protein and albumin concentrations were found to correlate with PV change, the use of the total spectral area of the plasma FT-IR spectra allowed a more precise measurement of PV change.

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Sun, Xue Z., Sergei M. Nikiforov, Jixin Yang, Christopher S. Colley, and Michael W. George. "Nanosecond Time-Resolved Step-Scan FT-IR Spectroscopy in Conventional and Supercritical Fluids Using a Four-Window Infrared Cell." Applied Spectroscopy 56, no. 1 (January 2002): 31–39. http://dx.doi.org/10.1366/0003702021954403.

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Fast time-resolved step-scan FT-IR (s2–FT-IR) has been used to study excited states and reaction intermediates in conventional and supercritical solvents. We have developed a four-port IR cell for s2–FT-IR measurements. The generation of W(CO)5(Xe), following photolysis of W(CO)6 in supercritical Xe, has been used to optimize our s2–FT-IR measurements in supercritical fluids using the four-port IR cell. We have compared a number of different approaches for obtaining transient time-resolved IR (TR-IR) data. The IR diode-laser-based and s2–FT-IR approaches for TR-IR have been compared directly. The kinetic decay of the CpMo(CO)3 (Cp = η5–C5H5) radical in supercritical CO2 has been determined using both TR-IR approaches, and we find no significant difference in signal-to-noise between these techniques for most of our TR-IR kinetic measurements. We have attempted to compare s2–FT-IR to the scanning dispersive TR-IR method by obtaining the infrared spectrum of the triplet excited state of 4-phenylbenzophenone, which has been published previously. The importance of obtaining high spectral resolution s2–FT-IR spectra for reactions in condensed phases is investigated. The IR spectrum of the CpFe(CO)2 radical in n-heptane shows that important information regarding the structure of the radical can only be obtained by performing time-resolved s2–FT-IR experiments at high spectral resolution.

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Dupuy, Nathalie, Jean Pierre Huvenne, Ludovic Duponchel, and Pierre Legrand. "Classification of Green Coffees by FT-IR Analysis of Dry Extract." Applied Spectroscopy 49, no. 5 (May 1995): 580–85. http://dx.doi.org/10.1366/0003702953964174.

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Principal component analysis (PCA) of infrared spectra has been used as a classification method for the green beans of coffee from various origin. Before spectral acquisition, sampling methods were tested for 45 samples, and we chose dry extract of water-soluble compounds on SiCaF2 supports. After PCA of the first derivatized spectra, the first four loadings were examined. The scores of the second principal component appear to be directly correlated by their sign to the species arabica or robusta. This result allows an easy classification. In the same way, the pigmentation is well characterized into two groups on the scattergram of the samples with respect to the PC1 and PC3 components. Another feature of this method is that the analysis of the spectral data in terms of residual variance separate components which are correlated with properties. This approach provides assistance in the interpretation of infrared spectra of complex mixtures.

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Rockley, N. L., and M. G. Rockley. "The FT-IR Analysis by PAS and KBr Pellet of Cation-Exchanged Clay Mineral and Phosphonate Complexes." Applied Spectroscopy 41, no. 3 (March 1987): 471–75. http://dx.doi.org/10.1366/0003702874448797.

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A comparison is made between the KBr pellet and FT-IR/PAS spectra of a series of interlamellar-cation-exchanged montmorillonites. Spectra of these clay minerals after adsorption of dimethyl methylphosphonate are also compared by the two spectroscopic methods. It is shown that the two infrared methods yield complementary spectral information, while FT-IR/PAS produces spectra with better definition of the adsorbate bands in all cases and superior reliability for observation of interlamellar ion-induced spectral shifts. Dimethyl methylphosphonate is shown to undergo interlamellar insertion, with bonding occurring directly through the P=0 moiety to the cation of the clay mineral. The strength of the bonding varies with the charge density of the cation.

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Jurdana, Lucia E., Kenneth P. Ghiggino, Ian H. Leaver, and Peter Cole-Clarke. "Application of FT-IR Step-Scan Photoacoustic Phase Modulation Methods to Keratin Fibers." Applied Spectroscopy 49, no. 3 (March 1995): 361–66. http://dx.doi.org/10.1366/0003702953963508.

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Step-scan FT-IR/PAS is shown to be a powerful tool for the nondestructive analysis of keratin fibers. Depth profiling studies were performed either by varying the optical velocity of the interferometer (scanning FT-IR/PAS depth profiling) or by a phase modulation method, utilizing a lock-in amplifier to separate the surface and bulk components of the signal phase. Both methods were shown to be capable of distinguishing spectroscopically between the cuticle and cortex of wool and hair fibers, the different spectral features being consistent with the differences in protein composition between these components. Phase-modulated spectra exhibited improved signal-to-noise ratios, with relatively little interference from saturation effects, compared with scanning FT-IR/PAS depth profile spectra.

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Grainger, James, Elizabeth Barnhart, Donald G. Patterson, and David Presser. "HPLC Separation and FT-IR Isomer Differentiation of the 1,2,4,7/1,2,4,8-Tetrachlorodibenzodioxin Isomer Pair—A Theoretical/Empirical Approach to Dibenzodioxin Isomer Assignment." Applied Spectroscopy 42, no. 2 (February 1988): 321–26. http://dx.doi.org/10.1366/0003702884428383.

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The 1,2,4,7- and 1,2,4,8-tetrachlorodibenzodioxin (TCDD) isomers were separated by reversed-phase high-performance liquid chromatography (HPLC) with the use of a pyrene column. Fourier transform infrared (FT-IR) matrix isolation and vapor-phase spectra of the individual isomers were recorded. The spectra of the HPLC-separated isomers correlate well with spectral subtraction results and were found to be distinct in three spectral regions—one of which allows for isomer structural assignment. Ambiguities and differences in published TCDD isomer FT-IR assignments are discussed in terms of a qualitative valence-bond approach and empirically derived estimates of ether linkage asymmetric stretching frequencies.

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37

Querido, William, Ramyasri Ailavajhala, Mugdha Padalkar, and Nancy Pleshko. "Validated Approaches for Quantification of Bone Mineral Crystallinity Using Transmission Fourier Transform Infrared (FT-IR), Attenuated Total Reflection (ATR) FT-IR, and Raman Spectroscopy." Applied Spectroscopy 72, no. 11 (July 20, 2018): 1581–93. http://dx.doi.org/10.1177/0003702818789165.

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Bone mineral crystallinity is an important factor determining bone quality and strength. The gold standard method to quantify crystallinity is X-ray diffraction (XRD), but vibrational spectroscopic methods present powerful alternatives to evaluate a greater variety of sample types. We describe original approaches by which transmission Fourier transform infrared (FT-IR), attenuated total reflection (ATR) FT-IR, and Raman spectroscopy can be confidently used to quantify bone mineral crystallinity. We analyzed a range of biological and synthetic apatite nanocrystals (10–25 nm) and found strong correlations between different spectral factors and the XRD determination of crystallinity. We highlight striking differences between FT-IR spectra obtained by transmission and ATR. In particular, we show for the first time the absence of the 1030 cm−1 crystalline apatite peak in ATR FT-IR spectra, which excludes its use for analyzing crystallinity using the traditional 1030/1020 cm−1 ratio. The ν4PO4 splitting ratio was also not adequate to evaluate crystallinity using ATR FT-IR. However, we established original approaches by which ATR FT-IR can be used to determine apatite crystallinity, such as the 1095/1115 and 960/1115 cm−1 peak ratios in the second derivative spectra. Moreover, we found a simple unified approach that can be applied for all three vibrational spectroscopy modalities: evaluation of the ν1PO4 peak position. Our results allow the recommendation of the most reliable analytical methods to estimate bone mineral crystallinity by vibrational spectroscopy, which can be readily implemented in many biomineralization, archeological and orthopedic studies. In particular, we present a step forward in advancing the use of the increasingly utilized ATR FT-IR modality for mineral research.

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Barańska, M., and L. M. Proniewicz. "FT-IR and FT-Raman spectra of cimetidine and its metallocomplexes." Journal of Molecular Structure 511-512 (November 1999): 153–62. http://dx.doi.org/10.1016/s0022-2860(99)00154-4.

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Wenning, Mareike, Herbert Seiler, and Siegfried Scherer. "Fourier-Transform Infrared Microspectroscopy, a Novel and Rapid Tool for Identification of Yeasts." Applied and Environmental Microbiology 68, no. 10 (October 2002): 4717–21. http://dx.doi.org/10.1128/aem.68.10.4717-4721.2002.

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ABSTRACT Fourier-transform infrared (FT-IR) microspectroscopy was used in this study to identify yeasts. Cells were grown to microcolonies of 70 to 250 μm in diameter and transferred from the agar plate by replica stamping to an IR-transparent ZnSe carrier. IR spectra of the replicas on the carrier were recorded using an IR microscope coupled to an IR spectrometer, and identification was performed by comparison to reference spectra. The method was tested by using small model libraries comprising reference spectra of 45 strains from 9 genera and 13 species, recorded with both FT-IR microspectroscopy and FT-IR macrospectroscopy. The results show that identification by FT-IR microspectroscopy is equivalent to that achieved by FT-IR macrospectroscopy but the time-consuming isolation of the organisms prior to identification is not necessary. Therefore, this method also provides a rapid tool to analyze mixed populations. Furthermore, identification of 21 Debaryomyces hansenii and 9 Saccharomyces cerevisiae strains resulted in 92% correct identification at the strain level for S. cerevisiae and 91% for D. hansenii, which demonstrates that the resolution power of FT-IR microspectroscopy may also be used for yeast typing at the strain level.

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Pasieczna-Patkowska, Sylwia, and Jarosław Madej. "Comparison of photoacoustic, diffuse reflectance, attenuated total reflectance and transmission infrared spectroscopy for the study of biochars." Polish Journal of Chemical Technology 20, no. 4 (December 1, 2018): 75–83. http://dx.doi.org/10.2478/pjct-2018-0057.

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Abstract Four infrared spectroscopic techniques - photoacoustic (PAS), diffuse reflectance (DRS), attenuated total reflectance (ATR) and transmission (TS) - were evaluated for the qualitative analysis of the biochar obtained from willow feedstock during pyrolysis. Increase in pyrolysis temperature resulted in more aromatic and carbonaceous structure of biochars. These changes could easily be detected from Fourier transform infrared (FT-IR) spectral differences. The comparison of the spectra obtained by the four FT-IR techniques allowed to conclude that there are differences in the spectra acquired using different IR technique caused by different signal acquisition. PAS and ATR were the best techniques used in order to obtain spectra with smooth and sharp peaks, in contrast to TS, where bands were less-separated. DRS turned out to be the weakest of all techniques, due to poor spectral quality and poor separation of the bands.

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41

Reffner, John A. "The Commercial Development of FT-IR Microspectroscopy." Microscopy Today 1, no. 3 (April 1993): 6–7. http://dx.doi.org/10.1017/s155192950006658x.

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Pittcon ‘93 marked the 10th anniversary of the introduction of a microscope attachment designed specifically for Fourier transform infrared microspectroscopy. The first commercial microscope developed for FT-IR spectroscopy was designed by Spectra-Tech, Inc., under the direction of then-owner D. W. Sting, in fulfillment of a contract with C. T. Foskett of the Digilab Division of BioRad. Digilab recognized a growing interest in the market for an FT-IR microscope and contracted with Spectra-Tech to design and build a microscope accessory for Digilab's FT-IR spectrometers. This microscope was introduced at the 1983 Pittsburgh Conference.Linking microscopy with Fourier transform spectroscopy was a very significant event, but the foundation of infrared microspectroscopy can be traced back to 1949. The explosive growth in the use of infrared-absorption spectroscopy following World War II led researchers R. Gore (in the U.S.A.), and R. Barer, A. R. Cole, and H. W. Thompson (in England), to investigate (in 1949) the possibility of recording infrared spectra of microscopic samples.

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Lange, Andrew J., and Peter R. Griffiths. "Use of Buffered Solvent Systems with Concentric Flow Nebulization Liquid Chromatography/Fourier Transform Infrared Spectrometry." Applied Spectroscopy 47, no. 4 (April 1993): 403–10. http://dx.doi.org/10.1366/0003702934335047.

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Identifiable Fourier transform infrared (FT-IR) spectra of species eluting from a high-performance liquid Chromatograph (HPLC) in buffered mobile phases are shown. The spectra are measured with the use of an online solvent-elimination HPLC/FT-IR interface based on direct-deposition concentric flow nebulization. Both volatile and nonvolatile buffers were used, in mobile phases consisting of 63–100% water. Examples of spectra of components separated by microbore HPLC using these buffered systems are shown. For the systems using nonvolatile buffers, spectral subtraction is needed to obtain analyte spectra, and absorption bands due to the buffer are rarely completely eliminated. For systems using volatile buffers, very little or no spectral subtraction is needed at low buffer concentrations. Minimum identifiable quantities in the low-nanogram range were achieved.

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43

Beduhn, Donald L., and Robert L. White. "Advantages of Dual-Beam Interferometry in Fourier Transform Infrared Spectrometry." Applied Spectroscopy 40, no. 5 (July 1986): 628–32. http://dx.doi.org/10.1366/0003702864508520.

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A dual-beam Fourier transform infrared spectrometer (FT-IR) is described. Sensitivity improvement, photometric accuracy, and instrument stability are evaluated by comparing dual-beam spectra with conventional single-beam spectra. Dual-beam FT-IR data acquisitions require an order of magnitude less measurement time than single-beam acquisitions for spectra of comparable signal-to-noise ratios. Application of dual-beam FT-IR for analysis of a highly transmitting sample is discussed. Single fiber analysis without masking and without an infrared microscope is described.

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Jaakkola, P., J. D. Tate, M. Paakkunainen, J. Kauppinen, and P. Saarinen. "Instrumental Resolution Considerations for Fourier Transform Infrared Gas-Phase Spectroscopy." Applied Spectroscopy 51, no. 8 (August 1997): 1159–69. http://dx.doi.org/10.1366/0003702971941683.

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Instrumental resolution has a significant effect on the performance of Fourier transform infrared (FT-IR) spectrometers used for gasphase analysis. Low-resolution FT-IR spectroscopy offers some valuable advantages compared with the traditional high-resolution FT-IR gas-phase spectroscopy, especially in nonlaboratory environments. First, high signal-to-noise ratio (SNR) spectra can be acquired in field conditions without the use of traditional liquid nitrogen-cooled detectors. Second, the dynamic range for quantitative analysis is larger for low-resolution spectroscopy than for high-resolution due to the lower absorbance values and lower noise levels. Third, spectral analysis speed is increased and data storage requirements are substantially reduced. The purpose of this study was to investigate the effect of instrumental resolution on FT-IR gas-phase analysis. The effects of spectral resolution on sensitivity, selectivity, accuracy, precision, spectral overlap, dynamic range, and nonlinearity are separately discussed.

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45

Richardson, Robert L., Husheng Yang, and Peter R. Griffiths. "Evaluation of a Correction for Photometric Errors in FT-IR Spectrometry Introduced by a Nonlinear Detector Response." Applied Spectroscopy 52, no. 4 (April 1998): 565–71. http://dx.doi.org/10.1366/0003702981943888.

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For strongly absorbing bands measured with a Fourier transform infrared (FT-IR) spectrometer, the effects of a nonlinear detector response must be eliminated before Beer's law linearity can be achieved. An empirical method for greatly reducing the effect of detector nonlinearity on FT-IR Beer's law spectra measured by using an FT-IR spectrometer equipped with a mercury-cadmium-telluride (MCT) detector is investigated. This first-order analytical function has been applied to correct nonlinear vapor-phase spectra and statistically evaluated for validity for spectral regions above the detector cutoff. In addition, a series of second-order functions has been evaluated to investigate the possibility that the transmittance scale is slightly nonlinear even after the first-order correction has been applied. Any improvement caused by the second-order functions was not statistically significant.

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Perut, Francesca, Gabriela Graziani, Laura Roncuzzi, Nicoletta Zini, Sofia Avnet, and Nicola Baldini. "FT-IR Spectral Signature of Sensitive and Multidrug-Resistant Osteosarcoma Cell-Derived Extracellular Nanovesicles." Cells 11, no. 5 (February 23, 2022): 778. http://dx.doi.org/10.3390/cells11050778.

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Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents. Despite aggressive treatment regimens, the outcome is unsatisfactory, and multidrug resistance (MDR) is a pivotal process in OS treatment failure. OS-derived extracellular vesicles (EVs) promote drug resistance to chemotherapy and target therapy through different mechanisms. The aim of this study was to identify subpopulations of osteosarcoma-EVs by Fourier transform infrared spectroscopy (FT-IR) to define a specific spectral signature for sensitive and multidrug-resistant OS-derived EVs. EVs were isolated from sensitive and MDR OS cells as well as from mesenchymal stem cells by differential centrifugation and ultracentrifugation. EVs size, morphology and protein expression were characterized. FT-IR/ATR of EVs spectra were acquired in the region of 400–4000 cm−1 (resolution 4 cm−1, 128 scans). The FT-IR spectra obtained were consistently different in the EVs compared to cells from which they originate. A specific spectral signature, characterized by a shift and a new band (1601 cm−1), permitted to clearly distinguish EVs isolated by sensitive and multidrug-resistant OS cells. Our data suggest that FT-IR spectroscopy allows to characterize and define a specific spectral signature for sensitive and MDR OS-derived EVs.

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Mouwen, D. J. M., M. J. B. M. Weijtens, R. Capita, C. Alonso-Calleja, and M. Prieto. "Discrimination of Enterobacterial Repetitive Intergenic Consensus PCR Types of Campylobacter coli and Campylobacter jejuni by Fourier Transform Infrared Spectroscopy." Applied and Environmental Microbiology 71, no. 8 (August 2005): 4318–24. http://dx.doi.org/10.1128/aem.71.8.4318-4324.2005.

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ABSTRACT Fourier transform infrared spectroscopy (FT-IR) has been used together with pattern recognition methodology to study isolates belonging to the species Campylobacter coli and Campylobacter jejuni and to compare FT-IR typing schemes with established genomic profiles based on enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Seventeen isolates were cultivated under standardized conditions for 2, 3, and 4 days to study variability and improve reproducibility. ERIC-PCR profiles and FT-IR spectra were obtained from strains belonging to the species Campylobacter coli and C. jejuni, normalized, and explored by hierarchical clustering and stepwise discriminant analysis. Strains could be differentiated by using mainly the first-derivative FT-IR spectral range, 1,200 to 900 cm−1 (described as the carbohydrate region). The reproducibility index varied depending on the ages of the cultures and on the spectral ranges investigated. Classification obtained by FT-IR spectroscopy provided valuable taxonomic information and was mostly in agreement with data from the genotypic method, ERIC-PCR. The classification functions obtained from the discriminant analysis allowed the identification of 98.72% of isolates from the validation set. FT-IR can serve as a valuable tool in the classification, identification, and typing of thermophilic Campylobacter isolates, and a number of types can be differentiated by means of FT-IR spectroscopy.

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Petibois, Cyril, Georges Cazorla, and Gérard Déléris. "Triglycerides and Glycerol Concentration Determinations Using Plasma FT-IR Spectra." Applied Spectroscopy 56, no. 1 (January 2002): 10–16. http://dx.doi.org/10.1366/0003702021954377.

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FT-IR spectrometry was used for plasma triglyceride and glycerol concentration measurements, based on their most characteristic IR absorbances within the 1200–800 cm−1 interval. Plasma samples from 68 sportsmen were taken at rest and after an endurance exercise that induced important lipolysis. After subtraction of glucose and lactate absorbances from exercise plasma FT-IR spectra, triglyceride concentration was accurately determined using the spectral window centered at 1106 cm−1 (0.86 ± 0.19 vs. 0.84 ± 0.17 mMol/L; r = 0.97, P < 0.01; SEP = 0.14 mMol/L). Total glycerol concentration (sum of glycerol and glyceryl residue concentrations) was determined using the spectral window centered at 926 cm−1, which was found common to triglycerides and glycerol (0.306 ± 0.057 vs. 0.326 ± 0.051 mMol/L; r = 0.98, P < 0.01; SEP = 0.02 mMol/L). Glycerol concentration could be determined using the spectral window centered at 852 cm−1 (0.216 ± 0.039 vs. 0.231 ± 0.048 mMol/L; r = 0.95, P < 0.01; SEP = 0.03 mMol/L). However, weak glycerol concentration could be only indirectly determined by subtracting glyceryl residue concentration from total glycerol concentration that had been determined using the spectral window centered at 926 cm−1 (0.191 ± 0.061 vs. 0.176 ± 0.051 mMol/L; r = 0.90, P < 0.05; SEP = 0.02 mMol/L). Indeed, FT-IR spectrometry appears to be an accurate method for multiple biomolecular concentration determination on plasma samples.

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Singh, P. K., Tanveer Hasan, Onkar Prasad, Leena Sinha, Kanwal Raj, and Neeraj Misra. "FT-IR spectra and vibrational spectroscopy of Andrographolide." Spectroscopy 20, no. 5-6 (2006): 275–83. http://dx.doi.org/10.1155/2006/463204.

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A complete normal coordinate analysis was performed for andrographolide in terms of the calculation by using Wilson's G-F matrix method and Urey Bradley force field. Normal coordinate analysis has been carried out to understand the dynamical behaviour of the bioactive labdane diterpenoid of the medicinally useful terrestrial plant Andrographis paniculata. The structural elucidation of a novel, biologically active natural product followed by its total synthesis lays the groundwork for investigations into its biological mechanism of action including putative cellular receptor isolation.

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Kopani, Martin, Milan Mikula, Daniel Kosnac, Jan Gregus, and Emil Pincik. "Morphology and FT IR spectra of porous silicon." Journal of Electrical Engineering 68, no. 7 (December 1, 2017): 53–57. http://dx.doi.org/10.1515/jee-2017-0056.

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AbstractThe morphology and chemical bods of p-type and n-type porous Si was compared. The surface of n-type sample is smooth, homogenous without any features. The surface of p-type sample reveals micrometer-sized islands. FTIR investigation reveals various distribution of SiOxHycomplexes in both p-and n-type samples. From the conditions leading to porous silicon layer formation (the presence of holes) we suggest both SiOxHyand SiFxHycomplexes in the layer.

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Journal articles on the topic 'FT-IR spectra'

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