FT-IR photoacoustic spectroscopy

Neubert, R. Collin, B. 8t Wartewig, S., Direct determination of drug content in semisolid formulations using step-scan FT-IR photoacoustic spectroscopy Pharm. Res. 1997, 14, 946-948. 

Further recent developments in DSC and IR techniques, with respect to the study of SC barrier properties, include step-scan FT-IR photoacoustic spectroscopy [195] and combined microscopic differential calorimetry-Four-ier transform infrared (DSC-FTIR) spectroscopy [196]. The former allows depth profiling of the membrane the latter enables the simultaneous detection of calorimetric and structural modifications during a thermal transition. Technological advances in DSC and IR will, no doubt, continue to expand the application of these techniques to the study of skin barrier function. 

JE McClelland, RW Jones, and SJ Bajic. FT-IR Photoacoustic Spectroscopy. In JM Chahners and PR Griffiths, eds. Handbook of Vibrational Spectroscopy. Chichester John Wiley, 2002, pp. 1231-1251. 

Yang, C.Q. Bresee, R.R. Fateley, W.G. "Near Surface Analysis and Depth Profiling with FT-IR Photoacoustic Spectroscopy" Appl. Spectrosc., in press. 

FT-IR photoacoustic spectroscopy (PAS) is rapidly gaining acceptance as a useful technique for the study of gases, liquids and solids. Most of the earlier references to the work on the PAS technique have been reviewed by Krishnan (11). Some of the earlier FT-IR PAS spectra have been presented by Vidrine (12). 

C. Deeley, J. Sellors and R. Spragg, A Comparison of FT Near IR Raman Spectroscopy, with FT-IR Photoacoustic and Reflection Measurements of Polymers, Perkin Elmer Infrared Spectroscopy Applications 14.3, Perkin Elmer Corporation, Norwalk, CT, USA, 1988. 

Sowa, M.G. and Mantsch, H.H, (1994) FT-IR photoacoustic depth profiling spectroscopy of enamel Calcif. Tissue Int, 54 (6), 481-485. 

Microphonic Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) has emerged as a useful tool for characterizing fractions of a monolayer of organic species adsorbed on opaque, high surface area samples. Such a study of calcined and sulfided hydrodesulfurization catalysts will be discussed. 

The technique employed is IR-FT photothermal beam deflection spectroscopy (PBDS). It is an off-shoot of photoacoustic spectroscopy (PAS) [1] and is based on the "mirage detection of the photothermal effect invented by Boccara et al. [2] and shown to result in a spectroscopic technique of remarkable versatility and utility. Some applications of "mirage spectroscopy," mainly in the visible, and theoretical treatments, have been described [3 6]. The method has now been developed for use in the IR. The spectrometer and techniques are described in detail elsewhere [7], but it will be useful to give a brief outline of the principles. 

ATR FT-IR spectroscopy has also been employed to monitor the solid-phase synthesis of substituted benzopyranoisoxazoles [180]. Finally, Huber et al. [181] have also reported that this technique is particularly suitable for the characterization of supported molecules in combinatorial chemistry, as well as for the identification of side products and for Photoacoustic (PA) FT-IR. 

Fourier transform infrared/photoacoustic spectroscopy (FT-IR/PAS) can be used to evaluate the secondary structure of proteins, as demonstrated by experiments on concanavalin A, hemoglobin, lysozyme, and trypsin, four proteins having different distributions of secondary... 

However, the improved sensitivity of FT-IR allows one to obtain better sensitivity using the conventional sampling accessories and expand the range of sampling techniques. Emission, diffuse reflectance and photoacoustic spectroscopy represent new areas where FT-IR reduces the difficulty of the techniques considerably. Greatly improved results are also achievable from reflection spectroscopy. Special effects such as vibrational circular dichroism can be observed using FT-IR instrumentation. 

Vibrational spectroscopy is a very versatile and, chemically, well-resolved technique for the characterization of carbon-oxygen functional groups. The immense absorption problems of earlier experiments seems to be overcome in present times with modem FT-IR, DRIFTS or photoacoustic detection instruments. 

Although the applications of photoacoustic FT-IR spectroscopy have shown several pi i] ir features in various sampling situations, the... 

Modulated infrared energy is absorbed by the sample. The material heats and cools in response to modulated infrared light. This response is converted into a pressure wave, which communicates with a surrounding gas. The pressure change is detected by an acoustic detector in the enclosed sample chamber. The necessary amount of sample material is less than 10 mg. The measuring time is about a few minutes, and the quality of the spectra is similar to that of the DRIFTS and ATR methods. The costs for the equipment are higher. A comparison of photoacoustic spectroscopy with all various FT-IR methods for the use in combinatorial chemistry was made by Yan et al. [12,13]. 

A variety of cellulose textile materials, including sized cotton yarns and chemically treated cotton fabrics were studied with fourier transform Infrared photoacoustic spectroscopy (FT-IR/PAS) in our laboratory. The distribution of chemical additives into cotton yarns and fabrics was determined using FT-IR/PAS. It is concluded that FT-IR/PAS is a non-destructive and information-rich analytical technique which is uniquely suitable to the near-surface characterization of a variety of cellulose textile materials. The fundamentals of FT-IR/PAS are also reviewed. 

Fourier Transform Infrared Photoacoustic Spectroscopy (FT-IR-PAS) has been developed recently. In this technique the standard... 

PAS-FTIR spectroscopy measurements were carried out on the JIR-SI X200 FT-IR spectrometer (JEOL Co. Ltd. Japan) equipped with a MTEC 300 photoacoustic cell (MTEC... 

Orlando, FL., Fall 1996, p.39-40. 012 HIGH-PRESSURE PHOTOACOUSTIC STEP-SCAN FT-IR SPECTROSCOPY OF POLYMERS Pennington B D Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science Engng.)... 

Dallas, Tx., Spring 1998, p.20-1. 012 STEP SCAN PHOTOACOUSTIC FT-IR SPECTROSCOPY AND STRATIFICATION PROCESSES IN THERMOPLASTIC OLEFINS (TPO)... 

Photoacoustic spectroscopy Mid-infrared spectra may be recorded by photoacoustic FT-IR spectroscopy from solids having a wide range of physical forms with minimal requirement for any sample preparation. 

Routine methods of chemical analysis can be applied to water-based coatings. For example, the nature of the binder can be determined by infrared spectroscopy. Water-resistant plates, such as KRS5 or zinc selenide, must be used if capillary films are cast from the aqueous dispersion. Dried films can be analyzed by surface-sensitive techniques such as attenuated total reflection (ATR) or photoacoustic spectroscopy (PAS). Both these techniques require the use of Fomrier transform infrared (FT IR) instruments to obtain spectra in a reasonable time. 

Jurdana LE, Ghiggino KP, Leaver IH, and Cole-Clarke P (1995) Application of FT-IR step-scan photoacoustic phase modulation methods to keratin fibres. Applied Spectroscopy 49 361-366. 

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