Time-resolved and fourier transform EPR studies of type I photochemical reaction. Direct determination of kinetic parameters of C−C bond cleavage

1996 ◽  
Vol 22 (2) ◽  
pp. 103-113 ◽  
Author(s):  
K. Akiyama ◽  
S. Tero-Kubota
Keyword(s):  
Fourier Transform ◽  
Kinetic Parameters ◽  
Photochemical Reaction ◽  
Bond Cleavage ◽  
Direct Determination ◽  
Type I ◽  
Time Resolved

Rheo-Optical Study of Polymers by Using Time-Resolved Soft-Pulse Compression Attenuated Total Reflection Step-Scan Fourier Transform Infrared Spectroscopy

2009 ◽  
Vol 63 (11) ◽  
pp. 1204-1210 ◽  
Author(s):  
Yuji Nishikawa ◽  
Tatsuhiko Nakano ◽  
Isao Noda
Keyword(s):  
Fourier Transform ◽  
Pulse Compression ◽  
Dynamic Compression ◽  
Pulse Frequency ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Type I ◽  
Type Ii ◽  
Time Resolved ◽  
2D Ir

A time-resolved soft-pulse dynamic compression attenuated total reflection (ATR) step-scan Fourier transform rheo-optical system has been developed. This system was used to observe different viscoelastic properties of polyethyleneterephthalate (PET) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx). Resonance features were observed in the dynamic compression ATR spectrum of PHBHx with 625 Hz soft-pulse frequency. In contrast, the dynamic compression ATR spectrum of PET showed no resonance features. The resonance feature of PHBHx was found at 1723 cm−1, which corresponds to the structural or morphological reorganization of a less ordered (Type II) crystalline form under compressive perturbation. The time-resolved evolution of infrared (IR) spectra was effectively analyzed by conventional generalized two-dimensional (2D) correlation analysis. The 2D-IR results indicate that the dynamic response of the well-ordered Type I crystalline state (1289 and 1261 cm−1) is faster than that of the Type II (1723, 1277, and 1228 cm−1). The present method shows promise for characterizing a wide variety of viscoelastic materials, including polymer alloys, blends, composites, and copolymers, and semicrystalline polymers.

Comparison of Univariate and Multivariate Strategies for the Determination of Sucrose in Fruit Juices by Automated Flow Injection Analysis with Fourier Transform Infrared Detection

1997 ◽  
Vol 51 (2) ◽  
pp. 227-235 ◽  
Author(s):  
R. Kellner ◽  
B. Lendl ◽  
I. Wells ◽  
P. J. Worsfold
Keyword(s):  
Fourier Transform ◽  
Flow Injection ◽  
Flow Injection Analysis ◽  
Fourier Transform Infrared ◽  
Fruit Juices ◽  
Enzyme Hydrolysis ◽  
Infrared Detection ◽  
Sample Treatment ◽  
Time Resolved

An automated technique for the determination of sucrose by flow injection analysis with Fourier transform infrared detection is presented. Two approaches to the quantitation of sucrose in synthetic and real sample matrices have been explored. The first was based on the on-line enzymatic hydrolysis of sucrose to α-d-glucose and β-D-fructose by β-fructosidase, with difference measurements being performed by using a flow injection manifold with two internally coupled injection valves. The manifold was optimized with time-resolved software and then automated with a custom-built TTL interface to transfer signals from the controlling program to the external apparatus. Univariate calibration was performed on the difference signals between the sucrose samples with and without enzyme hydrolysis. The second approach, using multivariate data analysis, negated the need for sample treatment and produced similar errors for the prediction of sucrose in different matrices within the established linear range of 0 to 100 mM. Both approaches have been successfully applied to the determination of sucrose in fruit juices.

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