A Comparison of Immersion Infrared Microspectroscopy to Attenuated Total Internal Reflection Microspectroscopy

Over the past several years many developments have taken place in the field of molecular spectroscopy. For Raman spectroscopy many of the improvements have arisen from technological innovations that include diode-based lasers, holographic notch filters and charged coupled detectors. In contrast, a majority of the developments in infrared spectroscopy have been in the area of new sampling accessories. A major emphasis has been placed on attenuated total internal reflection (ATR) accessories. The devices are allowing infrared spectroscopy to be employed in process control environments and quality control laboratories where the method is not only robust but has the advantages of limited sample preparation and/or in situ analysis.In the realm of microspectroscopy, ATR accessories have the added advantages of providing better spatial resolution, equal to or higher S/N for equivalent sample size compared to transmission measurements and most importantly the ability to collect spectra of small samples without the adverse effect of diffraction. One accessory which was developed several years ago is known as the Split-Pea.

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Attenuated Total Internal Reflection Infrared Mapping Microspectroscopy of Soft Materials

Applied Spectroscopy ◽

10.1366/0003702001949294 ◽

2000 ◽

Vol 54 (2) ◽

pp. 324-330 ◽

Cited By ~ 32

Author(s):

Lori L. Lewis ◽

André J. Sommer

Keyword(s):

Spatial Resolution ◽

Total Internal Reflection ◽

Soft Materials ◽

Diffraction Limit ◽

Internal Reflection ◽

Attenuated Total Internal Reflection ◽

Infrared Microspectroscopy ◽

Soft Samples ◽

Polymer Laminates

Attenuated total internal reflection (ATR) infrared mapping microspectroscopy of soft samples is reviewed and investigated by using cartridge-based germanium hemispheres. The study demonstrates the use of these devices for obtaining line scans or maps of soft pliable surfaces over an area of approximately 100 × 100 micrometers. An experimental determination of the spatial resolution by using a cross-sectioned polymer film showed a twofold improvement over transmission infrared microspectroscopy for sample sizes at the diffraction limit. Optical details of the devices are discussed in the context of ATR measurements in addition to their application for the study of polymer laminates often encountered in industry and forensics.

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Attenuated total internal reflection infrared microspectroscopy for the analysis of trace solutes in aqueous solutions

Vibrational Spectroscopy ◽

10.1016/s0924-2031(00)00082-5 ◽

2000 ◽

Vol 24 (1) ◽

pp. 93-100 ◽

Cited By ~ 5

Author(s):

André J Sommer ◽

Mark Hardgrove

Keyword(s):

Aqueous Solutions ◽

Total Internal Reflection ◽

Internal Reflection ◽

Attenuated Total Internal Reflection ◽

Infrared Microspectroscopy

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The Advantages of an Attenuated Total Internal Reflection Infrared Microspectroscopic Imaging Technique for the Analysis of Polymer Laminates

Microscopy and Microanalysis ◽

10.1017/s1431927615000410 ◽

2015 ◽

Vol 21 (3) ◽

pp. 626-636 ◽

Cited By ~ 1

Author(s):

Chen Ling ◽

André J. Sommer

Keyword(s):

Spatial Resolution ◽

Cross Sections ◽

Total Internal Reflection ◽

Imaging Technique ◽

Principal Component ◽

Internal Reflection ◽

Attenuated Total Internal Reflection ◽

Infrared Microspectroscopy ◽

Minimal Sample ◽

Polymer Laminates

AbstractUntil recently, the analysis of polymer laminates using infrared microspectroscopy involved the painstaking separation of individual layers by dissection or by obtaining micrometer thin cross-sections. The latter usually requires the expertise of an individual trained in microtomy and even then, the very structure of the laminate could affect the outcome of the spectral results. The recent development of attenuated total internal reflection (ATR) infrared microspectroscopy imaging has provided a new avenue for the analysis of these multilayer structures. This report compares ATR infrared microspectroscopy imaging with conventional transmission infrared microspectroscopy imaging. The results demonstrate that the ATR method offers improved spatial resolution, eliminates a variety of competing optical processes, and requires minimal sample preparation relative to transmission measurements. These advantages were illustrated using a polymer laminate consisting of 11 different layers whose thickness ranged in size from 4–20 μm. The spatial resolution achieved by using an ATR-FTIR (Fourier transform infrared spectroscopy) imaging technique was diffraction limited. Contrast in the ATR images was enhanced by principal component analysis.

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