Surface Selection Rule of Infrared Diffuse Reflection Spectrometry for Analysis of Molecular Adsorbates on a Rough Surface of a Nonabsorbing Medium

Seiya Morimine; Shingo Norimoto; Takafumi Shimoaka; Takeshi Hasegawa

doi:10.1021/ac5005025

Surface Selection Rule of Infrared Diffuse Reflection Spectrometry for Analysis of Molecular Adsorbates on a Rough Surface of a Nonabsorbing Medium

Analytical Chemistry ◽

10.1021/ac5005025 ◽

2014 ◽

Vol 86 (9) ◽

pp. 4202-4208 ◽

Cited By ~ 4

Author(s):

Seiya Morimine ◽

Shingo Norimoto ◽

Takafumi Shimoaka ◽

Takeshi Hasegawa

Keyword(s):

Rough Surface ◽

Selection Rule ◽

Diffuse Reflection ◽

Molecular Adsorbates ◽

Nonabsorbing Medium ◽

Diffuse Reflection Spectrometry

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Accurate Wavelength Measurements of a Putative Standard for Near-Infrared Diffuse Reflection Spectrometry

Applied Spectroscopy ◽

10.1366/000370203321535097 ◽

2003 ◽

Vol 57 (2) ◽

pp. 176-185 ◽

Cited By ~ 14

Author(s):

Tomas Isaksson ◽

Husheng Yang ◽

Gabor J. Kemeny ◽

Richard S. Jackson ◽

Qian Wang ◽

...

Keyword(s):

Near Infrared ◽

Diffuse Reflection ◽

Center Of Mass ◽

Baseline Correction ◽

Peak Picking ◽

Beam Path ◽

Polynomial Fit ◽

Vibration Rotation ◽

Rotation Spectrum ◽

Diffuse Reflection Spectrometry

The diffuse reflection (DR) spectrum of a sample consisting of a mixture of rare earth oxides and talc was measured at 2 cm−1 resolution, using five different accessories installed on five different Fourier transform near-infrared (FT-NIR) spectrometers from four manufacturers. Peak positions for 37 peaks were determined using two peak-picking algorithms: center-of-mass and polynomial fitting. The wavenumber of the band center reported by either of these techniques was sensitive to the slope of the baseline, and so the baseline of the spectra was corrected using either a polynomial fit or conversion to the second derivative. Significantly different results were obtained with one combination of spectrometer and accessory than the others. Apparently, the beam path through the interferometer and DR accessory was different for this accessory than for any of the other measurements, causing a severe degradation of the resolution. Spectra measured on this instrument were removed as outliers. For measurements made on FT-NIR spectrometers, it is shown that it is important to check the resolution at which the spectrum has been measured using lines in the vibration-rotation spectrum of atmospheric water vapor and to specify the peak-picking and baseline-correction algorithms that are used to process the measured spectra. The variance between the results given by the four different methods of peak-picking and baseline correction was substantially larger than the variance between the remaining five measurements. Certain bands were found to be more suitable than others for use as wavelength standards. A band at 5943.13 cm−1 (1682.62 nm) was found to be the most stable band between the four methods and the six measurements. A band at 5177.04 cm−1 (1931.61 nm) has the highest precision between different measurements when polynomial baseline correction and polynomial peak-picking algorithms are used.

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Reference Materials in Extended near Infrared Diffuse Reflection Spectrometry—The Misuse of Polytetrafluoroethylene

Journal of Near Infrared Spectroscopy ◽

10.1255/jnirs.81 ◽

1996 ◽

Vol 4 (1) ◽

pp. 107-110

Author(s):

Nathan C. Chaffin ◽

Peter R. Griffiths

Keyword(s):

Reference Material ◽

Reference Materials ◽

Near Infrared ◽

Diffuse Reflection ◽

Infrared Reflection ◽

Diffuse Reflection Spectrometry

This work reports that inherent absorption by polytetrafluoroethlyene precludes its use as a near infrared or extended near infrared reflection reference material. The effect of this inherent absorption on certain analyte bands is shown. The effectiveness of a previously published method for removing moisture and hydrocarbons from the surface of polytetrafluoroethylene is shown. It is suggested that diffuse gold should be used as the reflection reference material for all measurements made below 5000 cm−1.

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Diffuse reflection from a rough surface. I

Journal of Applied Spectroscopy ◽

10.1007/bf00607882 ◽

1967 ◽

Vol 7 (6) ◽

pp. 603-605 ◽

Cited By ~ 1

Author(s):

A. S. Toporets ◽

M. M. Mazurenko

Keyword(s):

Rough Surface ◽

Diffuse Reflection

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Role of Scattering Coefficients in Extended Near-Infrared Diffuse Reflection Spectrometry

Applied Spectroscopy ◽

10.1366/0003702981943527 ◽

1998 ◽

Vol 52 (2) ◽

pp. 218-221 ◽

Cited By ~ 9

Author(s):

Nathan C. Chaffin ◽

Peter R. Griffiths

Keyword(s):

Near Infrared ◽

Diffuse Reflection ◽

Index Of Refraction ◽

Scattering Coefficient ◽

Fresnel Reflection ◽

Scattering Coefficients ◽

The Matrix ◽

Bulk Scattering ◽

Diffuse Reflection Spectrometry

The role of the bulk scattering coefficient in extended near-infrared diffuse reflection (DR) spectrometry of materials with similar or identical absorption coefficients is demonstrated. Spectral differences that arise from intraclass variation in scattering coefficient strongly affect the ability to interpret certain spectral regions. Profound intraclass differences in both band intensities and band shapes in the DR spectra of both polyethylene and polystyrene samples are shown. The effects of saturation and Fresnel reflection are discussed. The enhancement of absorption by the matrix and other analytes in DR spectrometry through the addition of a liquid with an index of refraction which matches that of the matrix is also demonstrated.

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