Forensic applications of IR infrared microscopic internal reflection spectroscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1528-1529
Author(s):  
Edward G. Bartick ◽  
John A. Reffner
Keyword(s):  
Specular Reflection ◽  
Forensic Analysis ◽  
Attenuated Total Reflection ◽  
Internal Reflection ◽  
Standard Size ◽  
Ir Microscopy ◽  
Ir Analysis ◽  
Plastic Explosives ◽  
Internal Reflection Spectroscopy ◽  
Reflectance Measurements

Since the introduction of commercial Fourier transform infrared (FTIR) microscopic systems in 1983, IR microscopy has developed as an important analytical tool in research, industry and forensic analysis. Because of the frequent encounter of small quantities of physical evidence found at crime scenes, spectroscopic IR microscopes have proven particularly valuable for forensic applications. Transmittance and reflectance measurements have proven very useful. Reflection-absorption, specular reflection, and diffuse reflection have all been applied. However, it has been only very recently that an internal reflection (IRS) objective has been commercially introduced.The IRS method, also known as attenuated total reflection (ATR), has proven very useful for IR analysis of standard size samples. The method has been applied to adhesive tapes, plastic explosives, and general applications in the analysis of opaque materials found as evidence. The small quantities or uncontaminated areas of specimens frequently found requiring forensic analysis will often be directly applicable to microscopic IRS analysis.

The Structure of Lipids and Proteins Studied by Attenuated Total-Reflection (ATR) Infrared Spectroscopy

1972 ◽  
Vol 27 (7) ◽  
pp. 780-796 ◽  
Author(s):  
U. P. Fringeli ◽  
H. G. Müldner ◽  
Hs. H. Günthard ◽  
W. Gasche ◽  
W. Leuzinger
Keyword(s):  
Hexagonal Structure ◽  
Attenuated Total Reflection ◽  
Internal Reflection ◽  
Bilayer Structure ◽  
Reflection Spectroscopy ◽  
Langmuir Blodgett ◽  
Hydrocarbon Chains ◽  
Methylene Groups ◽  
Increasing Temperature ◽  
Internal Reflection Spectroscopy

The structure of tripalmitin multilayers prepared by the Langmuir-Blodgett technique has been investigated within room temperature and 62°C using infrared internal reflection spectroscopy (ATR). It was found that the bilayer structure exhibits crystalline features with pseudo hexagonal structure. The methylene groups of the hydrocarbon chains are in the all-trans-zig-zag conformation, oriented perpendicularly to the germanium internal reflection plate. Increasing temperature produces at first a continuous conformational change in the glycerol part of the molecule. This process is extended over nearly 10° and followed by sudden melting (disordering) of the hydrocarbon chains within 1°.In comparison microcrystalline tripalmitin shows an identical infrared spectrum and analogous behaviour at increased temperatures. This indicates that the bilayer structure (head-head, tail-tail) also exicts in the crystal.

scholarly journals Effect of SiO2 and TiO2 Nanoparticles on the Performance of UV Visible Fluorescent Coatings

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 928
Author(s):  
Sanja Mahović Poljaček ◽  
Tamara Tomašegović ◽  
Mirjam Leskovšek ◽  
Urška Stanković Elesini
Keyword(s):  
Tio2 Nanoparticles ◽  
Degradation Process ◽  
Bending Stiffness ◽  
Attenuated Total Reflection ◽  
Surface Coatings ◽  
Accelerated Ageing ◽  
Sem Images ◽  
Structural Surface ◽  
Uv Visible ◽  
Reflectance Measurements

In the present research, the properties of ultraviolet (UV) visible (daylight invisible) fluorescent coatings modified by the addition of SiO2 and TiO2 nanoparticles were studied. Structural, surface, and mechanical properties and changes in the coatings caused by accelerated ageing were analyzed. The results showed that the addition of nanoparticles caused the changes in unaged and aged printed coatings. Reflectance measurements of modified coatings showed that addition of TiO2 nanoparticles improved the visual effect of the unaged coatings. Furthermore, results have shown that the addition of SiO2 did not diminish the reflectance of the modified coatings after ageing. The results of roughness measurements showed that the addition of SiO2 decreased roughness after the ageing process, probably due to the degradation process indicated by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy. The roughness of the coatings with TiO2 nanoparticles was increased after the ageing on the samples with higher concentrations of TiO2 due to the agglomerates of plastisol formed on the surface of the coatings, visible in SEM images. Surface analysis of coatings showed that TiO2 caused an increase in the polarity of the surface coatings. Results of the bending stiffness showed that the addition of the nanoparticles to the coating, especially of SiO2, significantly improved the bending stiffness of the unaged samples.

Infrared spectroscopy of highk thin layer by multiple internal reflection and attenuated total reflection

2003 ◽  
Vol 0 (8) ◽  
pp. 2961-2965 ◽  
Author(s):  
N. Rochat ◽  
K. Dabertrand ◽  
V. Cosnier ◽  
S. Zoll ◽  
P. Besson ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Thin Layer ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Internal Reflection

scholarly journals Chemical Changes of Flattened Enamel Surfaces with in Vitro Weak Acid Demineralization

1971 ◽  
Vol 50 (6) ◽  
pp. 1589-1593 ◽  
Author(s):  
David J. Krutchkoff ◽  
Nathaniel H. Rowe
Keyword(s):  
Surface Chemistry ◽  
Weak Acid ◽  
Internal Reflection ◽  
Reflection Spectroscopy ◽  
Chemical Changes ◽  
Internal Reflection Spectroscopy

Infrared internal reflection spectroscopy (IRS) was used to study changes in surface chemistry of enamel after in vitro weak acid demineralization. Hypotheses that relate previous histomorphologic observations to current IRS findings are discussed.

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