Attenuated total internal reflection infrared spectroscopy

Attenuated Total Internal Reflection Infrared Spectroscopy (ATR)... 

The formulation of a sulfur-vulcanized styrene-butadiene rubber (R2) mainly contains the rubber polymer and precipitated silica as filler the rest of the components are minor in amount, but they are important to impart adequate vulcanization and protect the rubber from the degradation under use (mainly paraffin wax). The paraffin wax acts as a physical protecting agent against ozone by migration to the rubber surface (Romero-Sanchez and Martin-Martinez 2004). O Figure 43.6 shows the attenuated multiple total internal reflection-infrared spectroscopy (ATR-FTIR) spectrum of the R2 bulk. The main bands correspond to rubber (styrene and butadiene) and silica, and the presence of CH2 moieties are minor corresponding to the paraffin wax. However, the ATR-FTIR spectrum of the R2 surface shows the main bands due... 

Attenuated total refectance (ATR) infrared spectroscopy has been used to identify chemical species that are adsorbed to a germanium internal reflection element (IRE). We have described a method for depositing thin... 

Because infrared spectroscopy is an optical technique, the sample must be transparent in the spectral region of interest. Infrared spectroscopy can be used for heterogeneous samples and adsorbates on catalyst surfaces [11, 17]. If the sample cannot be made thin enough to be transparent, special probing techniques such as attenuated total internal reflectance can be use to monitor the concentration. 

Surface characterization by spectroscopic techniques yields information on the functional groups and elemental composition on the surface of polymeric biomaterials. The most common spectroscopic tools used for biomedical polymers are X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), and Fourier transform infrared spectroscopy (FTIR) (diffuse reflectance and attenuated total internal reflectance modes). Each of these techniques is discussed in the succeeding text. 

Applying attenuated total reflection Fourier transform infrared and total internal reflection fluorescence spectroscopy, the same group studied the secondary structure and aggregation properties of different proteins that are adsorbed onto planar PAA brushes (Hollmann, Steitz, Czeslik, 2008 Reichhart Czeslik, 2008). They found... 

Kun, R. Fendler, J. H. 2004. Use of attenuated total internal reflection-Fourier transform infrared spectroscopy to investigate the adsorption of and interactions between charged latex NPs. J. Phys. Chem. B 108 3462-3468. 

Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy. Attenuated total redectance (atr) ftir spectroscopy is based on the principle of total internal redection (40). Methods based on internal redection in the uv and visible regions of the spectmm are also common in addition to those in the ir region. The implementation of internal redection in the ir region of the spectmm provides a means of obtaining ir spectra of surfaces or interfaces, thus providing moleculady-specific vibrational information. 

Adam, M., Mossoba, M.M., and Lee, T. 2000. Rapid determination of total trans fat content by attenuated total reflection infrared spectroscopy An international collaborative study. J. Am. Oil Chem. Soc. 77 457-462. 

Infrared spectroscopy (IR) is a fairly simple in situ method. Since the absorption coefficients of molecular vibrations are rather low, it is impossible to detect the IR absorption of a molecule adsorbed or bonded to the semiconductor surface, merely by an ordinary vertical transmission measurement. This problem was solved by using attenuated total reflection (ATR) spectroscopy, as introduced by Harrick [17], and first applied to semiconductor-liquid junctions by Beckmann [18,19]. In this technique, the incident IR light beam is introduced via a prism into a semiconductor, at such an angle that total internal reflection occurs at the semiconductor-liquid interface, as illustrated... 

Numerous books cover the topic of sampling methods in infrared spectroscopy (see, e.g., references [10-12]), and a detailed description of all the various alternatives is beyond the scope of this chapter. Instead, we will focus on the two sampling methods that are most commonly employed in food analysis applications, namely, the use of transmission cells for recording the spectra of solutions and the total internal reflection technique, also known as attenuated total reflectance (ATR). Readers who wish to learn about the techniques not covered here may consult the references cited above. 

ATR-FTIR spectroscopy (attenuated total reflectance Fourier transform infrared spectroscopy)—IR spectroscopy uses the absorption of infrared radiation to probe the vibrational frequency of molecular motions. Attenuated total reflectance method uses a crystal of high refractive index to channel the infrared light (using total internal reflectance) into the crystal and causes only a thin layer of a sample in contact with the exterior of the crystal to be sensitively detected. 

Adsorption dynamics Ruorescence spectroscopy and microscopy (including immunofluorescence, total internal reflection fluorescence) Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) Quartz crystal microbalance (Spectroscopic) eUipsometry Reflectometric interference spectroscopy... 

Attenuated total reflection (ATR) spectroscopy is one of the most widely used techniques for surface infrared analysis. Although the phenomenon of total internal reflection of light was described by Newton in the early 17th century, it was not until much later that Harrick and, independently, Fahrenfort were to exploit this phenomenon to obtain absorption spectra and develop the ATR technique. When applied to the study of in situ kinetics of adsorption and reaction of species at liquid/ solid interfaces, ATR spectroscopy can yield valuable surface-chemical data. Such studies have been carried out in a variety of research and technological areas, including biomembranes, biofilms, thin film structure and reactivity, and electrochemistry. ... 

When light traversing an optically dense medium approaches an interface with a more optically rare medium at an angle exceeding a critical value, Bent = sin (rerare/ dens), total internal reflection occurs and an evanescent wave of exponentially deca5ung intensity penetrates the rarer medium. This phenomenon is at the heart of certain spectroscopic methods used to probe biomolecules at interfaces (199). In total internal reflection fluorescence (TIRF) spectroscopy (200-202), the evanescent wave excites fluorescent probes attached to the biomolecules, and detection of the emission associated with their decay provides information on the density, composition, and conformation of adsorbed molecules. In fourier transform infrared attenuated total reflection (FTIR-ATIR) spectroscopy (203,204), the evanescent wave excites certain molecular vibrational degrees of freedom, and the detected loss in intensity due to these absorbances can provide quantitative data on density, composition, and conformation. 

Attenuated Total Infrared Internal Reflectance (ATR) Spectroscopy (Spectra-Tech)... 

In materials investigations surface-sensitive techniques are of special interest. The major contribution of infrared spectroscopy to this field is internal reflection spectroscopy (IRS), often called the "attenuated total reflection" (ATR) technique. To describe theory and principle, electromagnetic wave theory must be apphed [33]. 

---