FTIR microscopy

Synchrotron radiation can be used as a source of IR for FTIR imaging it is hundreds or thousands of times brighter than the standard benchtop source it and is also pulsed and polarized [309], The extra brightness allows fast data collection at the diffraction-limited resolution 

A prime example of the use of FTIR microscopy is in the examination of polymers, a very important class of engineering materials. The physical properties of polymers are very dependent on their molecular structure. The presence of impurities, residual monomers, degree of crystallinity, size, and orientation of crystalline regions (the microstructure of a polymer) greatly affects their mechanical behavior. FTIR microscopy can identify polymers, additives, and determine the presence of impurities. 

In forensic science, FTIR microscopy has been used to examine paint chips from automobile accidents. An example of a paint chip spectmm is shown in Fig. 4.29. Hit-and-run drivers frequently leave traces of paint on cars with which they collide. Identification of the paint can help to identify the car. Other uses of an IR microscope in forensic analysis include the examination of hbers, dmgs, and traces of explosives. 

IR microscopy is used in the characterization of pharmaceuticals, catalysts, minerals, gemstones, adhesives, composites, processed metal surfaces, semiconductor materials, fossils, and artwork. Biological samples such as plant leaves and stems, animal tissue, cells, and similar samples can be imaged. Frequently, such information cannot be obtained by any other means. A microscope that combines both IR and Raman measurements will be discussed in the section on Raman spectroscopy. 

Reflectance slider b Objective Cassegrain Sample position Condenser Cassegrain View/IR mirror 

Q- Urethane alkyd 1 Match 77.00 Molecular formula 1 Sample prep film/KBr 

Other uses of an IR microscope in forensic analysis include the examination of fibers, drugs, and traces of explosives. For example, oxidation of hair can occur chemically or by sunlight oxidation of cystine to cysteic acid can be seen in hair fibers by FTIR microscopy (Robotham and Izzia). Excellent examples in full color of FTIR imaging microscopy can be found on the websites of companies like PerkinElmer and Thermo Fisher Scientific. Our limitations in use of gray scale make many of the examples unsuited for reproduction in the text. A novel IR microscope combined with atomic force microscopy, the nanoIR platform from Anasys Instruments (www.anasysinstruments.com), permits nanoscale IR spectroscopy, AFM topography, nanoscale thermal analysis, and mechanical testing. 

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The two most useful supplementary techniques for the light microscope are EDS and FTIR microscopy. Energy dispersed x-ray systems (EDS) and Eourier-transform infrared absorption (ETIR) are used by chemical microscopists for elemental analyses (EDS) of inorganic compounds and for organic function group analyses (ETIR) of organic compounds. Insofar as they are able to characterize a tiny sample microscopically by PLM, EDS and ETIR ensure rapid and dependable identification when appHed by a trained chemical microscopist. 

The FTIR technique has also the advantage of being easily associated to other techniques. For instance, the FTIR microscopy, which couples the visible image of the samples to the corresponding infrared spectra, allows the selection of microareas of interest, and thus an easy determination of the crystalline forms corresponding to different regions, in samples in which more than one polymorph is present [103]. 

Figure 3 FTIR microscopy absorbance spectra (100 pm aperture) recorded from a microtomed section through a defect area of a PES film. The upper spectrum is characteristic of the base film the lower spectrum is representative of the defect area. The difference in relative intensity of the band at 760 cm 1 can be clearly seen this band is attributable to the aryl-Cl end group. The consequence of this difference was the aryl-Cl end group deficient material processed differently giving rise to a gel-like feature in the polymer film. Reproduced with permission from Chalmers and Everall [1]. Copyright Wiley-VCH Verlag GmbH Co. KGaA.

Figure 16 (a) Schematic for obtaining a thin microtomed cross-section for FTIR microscopy... 

Microscopy-ftir technique, 79 564-565. See also Fourier transform infrared (Ftir) microscopy... 

Zolhfank, C. and Wegener, G. (2002). FTIR microscopy and ultrastructural investigation of sUylated solid wood. Hol orschung, 56(1), 39-42. 

The homogeneity of both the hydroperoxidation and grafting was confirmed by FTIR microscopy across a cross section of the films10. 

It is clear that the introduction of the IR FPA detector has brought Fourier transform infrared (FTIR) microscopy with a thermal source to a new and exciting stage of development. This is illustrated in the other chapters of this volume. Our purpose in this chapter is to address how IR FPA technology could be combined with the synchrotron source to advance IR spectroscopic imaging in ways that would prove quite difficult with a conventional thermal source. To address this question, we will need to understand the detailed nature of the synchrotron IR source, the optical... 

Loebbecke, C. S., Schweikert, W., Tuercke, T., Antes, J., Marioth, E., Krause, H., Applications of FTIR microscopy for process monitoring in silicon microreactors, in Proceedings of the VDE World Microtechnologies Congress, MICRO.tec 2000 (25-27 Sept. 2000),... 

Sommer AJ, Lang PL, Miller BS, Katon JE (1988) Application of molecular microspcctroscopy to paper chemistry. Prac Spectrosc 6 (Infrared Microspectrosc) 245-258 Sweeney KM (1989) FTIR microscopy of pulp and paper samples. Tappi J 72(2) 171-174 Wetzel DL (1983) Near-infrared reflectance analysis. Anal Chem 55 1165A-1176A Williams P, Norris K (1987) Near-infrared technology in the agricultural and food industries. 

Fourier transform infrared microscopy is the primary infrared technique for structural identification of materials at microquantities. The method is non-destructive and non-invasive. When using a proper transmittance sampling technique and a proper detector, the limit of detection can be as low as the picogram level. In the pharmaceutical industry, FTIR microscopy is used to analyze bulk drugs, excipients, and particulate contaminants. " Recent studies have shown that by coupling FTIR microscopy with GC, HPLC, SFC, or GPC systems, the detection limit of the method is substantially improved. ... 

In principle, operation of the FTIR microspectroscopy is the same as for a conventional FTIR instrument except the spectrum is obtained from a microscopic area or intensity distribution is mapped in the sample plane. A spectrum from an area in the order of 10 x 10 /im can be obtained. Mapping or FTIR imaging at micro-level resolution can be achieved by scanning a sample using a motorized sample stage. The resolution is primarily determined by the size of the focused IR beam and precision of motorized stage. Reflectance microspectroscopy is more widely used than the transmittance mode in FTIR microscopy because minimal sample preparation is required. 

De Miguel, Y., Shearer, A.R. and Alison, S. (2001) Infrared spectroscopy in solid-phase synthesis. Biotechnol. Bioeng. 71 119-129. Yan, B., Fell, J. B. and Kumaravel, G (1996) Progression of organic reactions on resin supports monitored by single bead FTIR microscopy. J. Org. Chem. 61 7467-7472. 

These experiments confirmed that IR spectroscopy indeed provides a promising means for the investigation of the uptake of binary mixtures into microporous materials and its kinetics. This successful experiment prompted us to start a systematic study on the adsorption and adsorption kinetics of some aromatics in zeolites by Fourier transform IR spectroscopy (FTIR) and FTIR microscopy or, more precisely, IR micro -spectroscopy. This topic is dealt with in Sect. 2, where the generally employed apparatuses and procedures are also described. In this context, it should be mentioned that micro-FTIR spectroscopy was also applied by Schiith and coworkers in studying the adsorption of guest molecules in microporous soHds [ 12-14]. 

Fig. 4 a Schematic setup for experimental studies of sorption and sorption kinetics by micro -FTIR spectroscopy (so-called FTIR microscopy), b Flow cell for micro-FTIR investigations of sorption and sorption kinetics in zeolites [30,31]... 

FTIR microscopy was discussed earlier in the chapter, and given the complementary nature of IR and Raman, it is reasonable that laboratories performing IR microscopy might well need Raman microscopy and vice versa. Two microscope systems were required and the sample had to be moved from one system to the other. The difficulty of relocating the exact spot to be sampled can be imagined. A new combination dispersive Raman and FTIR microscopy system was introduced in 2002. The system, called the LabRam-IR (JY Floriba, Edison, NJ), allows both Raman and IR spectra to be collected at exactly the same location on the sample. The resolution depends on the... 

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