Attenuated total reflectance infrared microspectroscopy of coal

Fuel ◽  
2000 ◽  
Vol 79 (6) ◽  
pp. 685-691 ◽  
Author(s):  
J. Thomasson ◽  
C. Coin ◽  
H. Kahraman ◽  
P.M. Fredericks
Keyword(s):  
Attenuated Total Reflectance ◽  
Total Reflectance ◽  
Infrared Microspectroscopy

Rapid Differentiation of Bacillus Strains Using Hydrophobic Grid Membranes and Attenuated Total Reflectance Infrared Microspectroscopy

2009 ◽  
Vol 72 (9) ◽  
pp. 1909-1915 ◽  
Author(s):  
ELIZABETH M. GRASSO ◽  
AHMED E. YOUSEF ◽  
LUIS A. RODRIGUEZ-ROMO ◽  
LUIS E. RODRIGUEZ-SAONA
Keyword(s):  
Food Industry ◽  
Strain Level ◽  
Attenuated Total Reflectance ◽  
Bacillus Species ◽  
Total Reflectance ◽  
Infrared Microspectroscopy ◽  
Molecular Identification Methods ◽  
Ir Microspectroscopy ◽  
Multivariate Pattern

Bacillus species may be resistant to processing and sanitation procedures, making their control an important issue in the food industry. The objective of this study was to develop a rapid method for the differentiation of Bacillus cells at the strain level using infrared microspectroscopy and multivariate pattern recognition techniques. Aliquots (10 ml) of vegetative cells (~103 CFU/ml) from four strains of each of three Bacillus species (B. cereus, B. mycoides, and B. thuringiensis) were filtered onto hydrophobic grid membranes. The membranes were placed on tryptic soy agar and incubatedat 42°C for 24 h and then removed from the agar and dried, and the biomass of individual vegetative colonies was directly measured by attenuated total reflectance infrared (ATRIR) microspectroscopy. Soft independent modeling of class analogy models generated from second derivative transformed spectra in the 1,300 to 900 cm−1 region exhibited clusters that permitted accurate strain-level classification of all isolates. Major discrimination was related to the signal from phosphate-containing compounds, likely phospholipids. Results indicate that a simple ATR-IR microspectroscopy technique combined with multivariate analysis could provide the food industry with a rapid and reagent-free screening procedure to complement more elaborate molecular identification methods.

Crack analysis of unfilled natural rubber using infrared microspectroscopy

1996 ◽  
Vol 54 ◽  
pp. 256-257
Author(s):  
L. A. Neumeister ◽  
J. L. Koenig
Keyword(s):  
Natural Rubber ◽  
Cross Section ◽  
Crack Tip ◽  
Molecular Structures ◽  
Attenuated Total Reflectance ◽  
Spectroscopic Methods ◽  
Total Reflectance ◽  
Infrared Microspectroscopy ◽  
Molecular Scale

Several spectroscopic methods are available for characterizing the crack tip region of natural rubber on the molecular scale to develop a material with fatigue resistant properties. Attenuated total reflectance or ATR-IR has been used to characterize the structure of many different polymers, including rubbers. Transmission has also been well established as a viable technique for the molecular characterization of transparent materials including thin films of unfilled natural rubber.Unfilled natural rubber was stretched to 629% elongation until cracks appeared in the surface. A cross section of the sample containing a crack was then microtomed at -85°C into slices approximately 0.5 µm thick. Similarly, samples were cut with a razor and microtomed under the same conditions. The crack tip region was mapped using the IRμs™/SIRM Molecular Microanalysis System. The map consisted often spectra taken in the x and y directions as shown in Figure 1. The same region was analyzed for orientation of molecular structures. Points were selected along the crack tip, crack edges, and the bulk. Dichroic ratios of all prominent peaks were calculated. ATR was used to verify the results of the mapping experiments for both stressed and unstressed material.

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