Spectroscopy attenuated total reflectance

The depth of penetration in ATR spectroscopy is a function of the wavelength (X), the refractive index of the crystal and the angle of incident radiation (9). The depth of penetration, for a nonabsorbing medium is given by the following formula  

The crystals used in ATR cells are made from materials which have low solubility in water and are of very high refractive index. Such materials include zinc selenide (ZnSe), germanium (Ge) and thallium/iodide (KRS-5). The properties of these commonly used materials for ATR crystals are summarised in Table 3.3. Different designs of ATR cells allow both liquid and solid samples to be examined. 

It is also possible to set up a flow-through ATR cell by including both an inlet and an outlet arrangement in the apparatus. This allows for the continuous flow of solutions through the cell and thus permits spectral changes with time to be monitored. 

1 KRS-5 (thallium/iodide) 17000-250 2.4 Soluble in bases slightly soluble in water insoluble in acids soft highly toxic (handle with gloves) 

ZnSe 20000-500 2.4 Insoluble in water, organic solvents, dilute acids and bases 

Fundamentals. A plane wave of electromagnetic radiation (i.e. light) impinging upon an interface between two media of different optical density from the medium with the higher refractive index will be reflected totally (internally) pro- 

Instrumentation. A setup employing an ITO-coated glass sheet as the working electrode and ATR element as shown in Fig. 5.12 has been proposed for studies of thin films deposited on the ITO layer [64]. Light is piped through an optical fiber to 

For further details, see the corresponding section in Sect. 5.1.2 on infrared spectroscopy. 

Spectral information is gathered from species within the range of the evanescent wave penetration length at the ITO-solution interface. The reported cell design 

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Attenuated total reflectance spectroscopy and reflection-absorption infrared spectroscopy... 

M. W. AT2rs1, Attenuated Total Reflectance Spectroscopy of Polymers Theory and Practice, American Chemical Society, Washington, D.C., 1996. 

While electron or ion beam techniques can only be applied under ultra-high vacuum, optical techniques have no specific requirements concerning sample environment and are generally easier to use. The surface information which can be obtained is, however, quite different and mostly does not contain direct chemical information. While with infra-red attenuated total reflection spectroscopy (IR-ATR) a deep surface area with a typical depth of some micrometers is investigated, other techniques like phase-measurement interference microscopy (PMIM) have, due to interference effects, a much better surface sensitivity. PMIM is a very quick technique for surface roughness and homogeneity inspection with subnanometer resolution. 

In infra-red attenuated total reflection spectroscopy (IR-ATR) and grazing incidence reflection IR spectroscopy (IR-GIR) the evanescent wave of a totally... 

In another study, ATPase reconstituted into liposomes was analyzed by infrared attenuated total reflection spectroscopy and the secondary-structure elements of the molecule were determined from the spectra obtained by Fourier self-deconvolution [42]. Gratifyingly, essentially identical secondary-structure estimates for the ATPase were obtained by this entirely different approach, suggesting quite strongly that these secondary-structure estimates are reasonably accurate. Thus, any future models for the structure of the H -ATPase must take this information into account. 

F.M. Mirabella, Attenuated total reflection spectroscopy, in Modem Techniques in Applied Molecular Spectroscopy, F.M. Mirabella, Fd., Wiley Scientific, New York, 1998, Chap. 4, pp. 127-184. 

Solymar, L. and Walsh, D. 1998. Electrical Properties of Materials. Oxford University Press, New York. Turi, E. 1997. Thermal Characterization of Polymeric Materials, 2nd ed. Academic Press, Orlando, PL. Urban, M. 1996. Attenuated Total Reflectance Spectroscopy of Polymers. Oxford University Press, New York. 

A variety of eell designs for internal reflection or attenuated total reflection spectroscopy have been reported, demonstrating the flexibility of the technique. In the following, we describe only a few examples in some detail. 

Urban, M.W., Attenuated Total Reflection Spectroscopy of Polymers." American Chemical Society, Washington, DC, 1996. 

Mossoba, M.M., Yurawecz, M.P., and McDonald, R.E. 1996. Rapid determination of the total trans content of neat hydrogenated oils by attenuated total reflection spectroscopy. J. Am. Oil Chem. Soc. 73 1003-1009. 

Urban MW (1996) Attenuated Total reflectance spectroscopy of polymers polymer surfaces and interfaces series. ACS, Washington DC... 

DiesselE, Willmann S, Kamphaus P, Kurte R, Damm U, Heise HM. Glucose quantification in dried-down nanoliter samples using mid-infrared attenuated total reflection spectroscopy. Applied Spectroscopy 2004, 58, 442-450. 

In an effort to gain a better understanding of the initial fouling step leading to bacterial attachment and biofilm formation, we have investigated the adsorption of protein and polysaccharides onto thin metallic films and uncoated internal reflection elements from flowing solutions using attenuated total reflectance spectroscopy. The preliminary results will be described in this paper. 

Y. Takeuchi, H. Yasukawa, Y. Yamaoka, Y. Kato, Y. Morimoto, Y. Fukomori, and T. Fukada, Effect of fatty acids, fatty amines and propylene glycol on rat stratum corneum hpids and proteins in vitro measured by Fourier Transformed Infrared/Attenuated Total Reflectance spectroscopy. Chem. Pharm. Bull. 40 1887-1892 (1992). 

ID IQ 2D 2D-NMR 2h2o 2Q 3Q 9BEN A1 ABS AC ACM ACN AFM Al-CSM ALMA-i5 Al-m-EPDM AN AO APT ASTM ATR ATR-IR B/S BABA Two-dimensional Single-quantum One-dimensional Deuteron solid-state NMR Deuterated water Double-quantum Triple-quantum 9 borobicyclo [3, 3, 1] nonane Amide 1 Acrylonitrile-butadiene-styrene terpolymer Accelerator Acrylate rubber Acrylonitrile Atomic Force Microscopy Aluminium salt of chlorosulfonate polyethylene Allyl-rf5 methacrylate Aluminium salt of maleated EPDM Acrylonitrile 1-Allyl oxyoctane Attached Proton Test American Standards for Testing and Materials Attenuated total reflectance spectroscopy Attenuated total reflectance-IR spectroscopy Butadiene/styrene Back-to-back... 

Fluctuations in the dielectric properties near the interface lead to scattering of the EW as well as changes in the intensity of the internally reflected wave. Changes in optical absorption can be detected in the internally reflected beam and lead to the well-known technique of attenuated total reflectance spectroscopy (ATR). Changes in the real part of the dielectric function lead to scattering, which is the main topic of this review. Polarization of the incident beam is important. For s polarization (electric field vector perpendicular to the plane defined by the incident and reflected beams or parallel to the interface), there is no electric held component normal to the interface, and the electric field is continuous across the interface. For p polarization (electric field vector parallel to the plane defined by the incident and reflected beams), there is a finite electric field component normal to the interface. In macroscopic electrodynamics this normal component is discontinuous across the interface, and the discontinuity is related to the induced surface charge at the interface. Such discontinuity is unphysical on the molecular scale [4], and the macroscopic formalism may have to be re-examined if it is applied to molecules within a few A of the interface. 

Mendes SB, Li LF et al (1996) Broad-band attenuated total reflection spectroscopy of a hydrated protein film on a single mode planar waveguide. Langmuir 12(14) 3374—3376... 

K. Sawara, T. Yasaka, S. Miyazaki, andM. Hirose, Atomic scale Harness of chemically cleaned silicon surfaces studied by infrared attenuated-total-reflection spectroscopy, Jpn. J. Appl. Phys. 31, L931, 1992. 

W. Theia, M. Wemke, and V. Offermaim, Depth profiling of porous silicon layers by attenuated total reflection spectroscopy. Thin Solid Films 255, 181, 1995. 

Fourier transform infrared spectroscopy (FTIR) and attenuated total reflectance spectroscopy can give information on adsorbed species. 

E. Zippel, M. W. Breiter, and R. Kellner, Fourier-transform Infrared, Attenuated Total Reflection Spectroscopy A Complementary Tool for the Ivestigation of the Adsorption of CO on Thin Metal Layers, J. Chem. Soc. Faraday Trans. 87, 637-642 (1991). 

Another technique that is important for optical immunosensor development is internal or attenuated total reflection spectroscopy (Fig. 126). A waveguide (slide or fiber) having a high refractive index is coated with a layer of immobilized antibody. The incident light... 

ATR (Attenuated Total Reflection) spectroscopy [27] was invented and applied mainly for investigations of surfaces.This method entails an experimental set-up which reflects the IR beam via a mirror system to a crystal with a high refraction index. Normally, germanium (refraction index n = 4), silver chloride (n = 2) or diamond (n = 2,4) crystals are used. The crystal is standing in direct contact with the surface of the sample (Fig. 16.3). 

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