Horizontal attenuated total reflection

HATR Horizontal attenuated total reflectance infrared spertroscopy... 

The bisphenol A contents of PVC stretch films for food packaging were investigated. Major components were identified by FTIR and horizontal attenuated total reflectance. Migration of bisphenol A from these materials was determined by HPLC using both fluorescence and UV detection. 33 refs. 

A method of horizontal attenuated total reflectance (HATR) by Fourier transform infrared spectroscopy (FTIR) is considered more useful for infrared spectroscopic analysis of leather samples. By this method, the sample is simply put on the flat plate of ZnSe crystal or KRS-5 crystal of the HATR accessory. The Fourier transformation of the interferogram is converted by the computer into a plot of absorption against wave number that resembles the usual IR spectrum (William and Fleming, 1998). 

Eerrao, M.E. and Davanzo, C.U. (2005) Horizontal attenuated total reflection applied to simultaneous determination of ash and protein contents in commercial wheat flour A aZ Chim Acta, 540 (2), 411-415. 

The second sample appeared to be black sooty metallic shavings. Following solvent extractions of this material with xylene and Freon, the solvents were evaporated, and the residues were analyzed by FTIR spectrometry. Because chlorinated solvents attack the epoxy that secures the zinc selenide crystal to the horizontal attenuated total reflectance (HATR) boat. Freon was air dried from the residue. The residue was resolvated in acetone for mounting purposes. 

Use of a horizontal attenuated total reflectance (HATR) accessory detection range = 0.3 M to 1.0 M... 

Figure 15.7. Horizontal attenuated total reflection (HATR) accessory with a trapezoidal internal reflection element. (Courtesy of PIKE Technologies.)...

If the sample is placed in good contact with the surface of an optical device of high refractive index (such as a prism of KRS-5) and illuminated through the prism by IR, the beam passes into the layers in contact and is attenuated before being totally internally reflected by the system, as shown in Figure 5(b). This is called attenuated total reflectance or ATR. If the beam interacts several times, then we have multiple internal reflectance (MIR) and if the surface is horizontal, which is an advantage in setting up the sample, then it is horizontal attenuated total reflectance (HATR). 

Raman spectroscopy has a definite advantage for biological systems in that absorption bands due to water do not present a problem. However, fluorescence may present a major problem for some samples when examined by Raman techniques and photochemical interactions may need to be borne in mind. The use of horizontal attenuated total reflectance techniques has become more popular for the study of aqueous solutions of biological samples. 

Using internal reflection, also known as attenuated total reflection (ATR), an official ATR-FTIR method (AOCS, 1999a AOAC International, 2000) was recently developed (Mossoba et al., 1996, 2001b Adam et al., 2000) to rapidly (5 min) measure the 966 cm-1 trans band as a symmetric feature on a horizontal baseline (Fig. Dl.7.1 A). The experimental aspects of this ATR infrared official method are far less complex than those involving the conventional transmission measurements. This approach entails (1) ratioing the trans test sam-... 

The attenuated total reflection (ATR) method measures the reflection coefficients of vertically and horizontally polarized light reflected from a polymer layer adsorbed on a transparent surface63. These coefficients allow the thickness of the adsorbed layer and the polymer concentration in it to be determined. 

NMR spectra were recorded using Bruker Biospin AV200 spectrometer (at 200 MHz for protons). Infrared spectra were recorded on a Bio-Rad FTS-40 attenuated total reflection Fourier transform IR (ATR-IR) using a horizontal ATR apparatus with a cadmium selenide crystal. Surface roughness was measured by an interferometerom-eter, which generates a 3D profile (Veeco WYKO NTllOO optical profiler). 

Fourier transform infrared spectroscopy (FT-IR) is useful for identifying organic and inorganic compounds by comparison with library references. Perkin Elmer System 2000 offers near IR, mid IR, far IR 15,000-15,030 cm, transmittance (T), specular reflectance (SR Ref. 6) and diffuse reflectance (DR), horizontal and vertical attenuated total reflectance (ATR) microscope (>10-gm spot, 10,000-10,580 cmy ... 

Infrared spectra were taken using a Nicolet Nexus 670 Fourier transform infrared (FTIR) spectrometer equipped with a single horizontal golden gate attenuated total reflectance fATR) cell. Spectra were recorded using a spectral width ranging from 600 to 4000 cm with 2 cm resolution and an accumulation of 20 scans. 

Figure 1 shows two spectra from two sections of a modern painting. The damage to the picture might have been caused by a heterogeneous application of oil or the poor conservation of the picture. A non-homogeneous distribution of oil over the surface was made evident when two sections of the picture were analysed. As it was possible to use part of the picture from under the frame, the amount of sample was sufficient to allow use of the attenuated total reflectance horizontal accessory. 

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