Quantitative Analysis By Fourier Transform Infrared Photoacoustic Spectroscopy.

1988 ◽  
Author(s):  
P S. Belton ◽  
A M. Saffa ◽  
R H. Wilson
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Photoacoustic Spectroscopy ◽  
Fourier Transform Infrared ◽  
Infrared Photoacoustic Spectroscopy

Quantitative Analysis of a Binary Mixture by Fourier Transform Infrared Photoacoustic Spectroscopy

1981 ◽  
Vol 35 (2) ◽  
pp. 185-186 ◽  
Author(s):  
Mark G. Rockley ◽  
Dennis M. Davis ◽  
Hugh H. Richardson
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Binary Mixture ◽  
Photoacoustic Spectroscopy ◽  
Fourier Transform Infrared ◽  
Isotopic Shift ◽  
Infrared Photoacoustic Spectroscopy

The isotopic shift of the v2 NO3−1 absorption of mixtures of K15NO3 and K14NO3 at 800 and 825 cm−1 has been used to demonstrate that Fourier transform infrared photoacoustic spectroscopy is a technique which is useful for quantitative analysis of solid mixtures.

Quantitative Determination of Catalytic Surface Adsorption Sites by Fourier Transform Infrared Photoacoustic Spectroscopy

1983 ◽  
Vol 37 (2) ◽  
pp. 131-133 ◽  
Author(s):  
Joseph A. Gardella ◽  
Da-Zhen Jiang ◽  
Edward M. Eyring
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Calibration Curve ◽  
Photoacoustic Spectroscopy ◽  
Surface Adsorption ◽  
Fourier Transform Infrared ◽  
Catalytic Surface ◽  
Adsorption Sites ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

The use of Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) as a method for quantitative analysis of surface adsorption sites is demonstrated. Mid-IR information about the amount of adsorption is available with the sampling advantages of PAS: ability to analyze opaque materials with minimal sample preparation, qualitative information about both gas [CO(g)] phase and adsorbed [CO(ads)] species, a sealed sample environment for control of the gas phase in contact with the sample, and the ability to monitor in situ reaction kinetics. In this study a calibration curve is constructed for the amount of CO(g) in the sample cell with a silica internal reference. This calibration curve is utilized to calculate the amount of CO(ads) by subtraction on a catalytic surface where both CO(g) and CO(ads) exist at equilibrium. Using standard parameters from gas titration/volume uptake studies, the surface covered and the percentage of active sites on the surface are determined. This analysis combines the qualitative analytical capabilities of PAS with quantitative analysis, thus demonstrating another facet of the usefulness of FT-IR/PAS in addressing unusual problems.

Depth Profile Study of Large-Sized Coal Samples by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (2) ◽  
pp. 214-217 ◽  
Author(s):  
Tiziana Zerlia
Keyword(s):  
Fourier Transform ◽  
Depth Profile ◽  
Photoacoustic Spectroscopy ◽  
Modulation Frequency ◽  
Fourier Transform Infrared ◽  
Qualitative Description ◽  
Difference Spectra ◽  
Compositional Depth Profile ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

A multidisciplinary approach is demonstrated to elucidate coal weathering at a molecular level. Fourier Transform Infrared Photoacoustic Spectroscopy (FT-IR/PAS) provides a technique for a compositional depth profile of coal by simply varying the modulation frequency (mirror velocity) of the light impinging upon the solid surface. In order that the potential of this technique in this field could be evaluated, large-sized coal samples were examined. The PA difference spectra obtained from the spectra taken at different modulation frequencies (i.e., different depths), on a sample aged in air, demonstrate the appearance of negative features in the CH infrared absorption which are indicative of a coal alteration. Therefore, different coal layers can be distinguished by FT-IR/PAS. The application of the same technique to the study of a coal sample heated in air at 200°C allows the detection of different oxidation mechanisms operating inside and outside the coal. Although quantitative results are difficult to obtain, the technique can be successfully proposed for a qualitative description of coal weathering.

Determination of the Orientation of Silanes on Silica Surfaces by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (4) ◽  
pp. 513-519 ◽  
Author(s):  
Marek W. Urban ◽  
Jack L. Koenig
Keyword(s):  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Surface Coverage ◽  
Silica Surface ◽  
Fourier Transform Infrared ◽  
Coupling Agents ◽  
Surface Hydroxyl ◽  
Silica Surfaces ◽  
Quantitative Surface Analysis ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic spectroscopy has been used for quantitative surface analysis of silica treated with trifunctional coupling agents such as γ-Methacryloxypropyltriethoxysilane (γ-MPS), γ-Glycidoxypropyltrimethoxysilane (γ-GPS), and γ-Aminopropyltri-ethoxysilane (γ-APS). The calibration curves are obtained for several characteristic bands of the coupling agents. Using a highly polarizable gas in the photoacoustic cell and comparing the spectra with a nonpolarizable coupling gas, it is possible to evaluate orientation of the coupling agents on the silica surface. The type of orientation is a function of the extent of surface coverage. At low surface coverage, coupling agents tend to take a perpendicular orientation with respect to the surface, and increasing surface coverage leads to parallel orientation. Increasing the coupling agent concentration also causes orientational changes of the species which form chemical bonds with the silica surface (hydroxyl, water, and carbonyl groups).

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