On Line Infrared Identification of Gas Chromatography Effluents

1975 ◽  
Vol 29 (1) ◽  
pp. 24-28 ◽  
Author(s):  
B. Katlafsky ◽  
M. W. Dietrich
Keyword(s):  
Gas Chromatography ◽  
Functional Groups ◽  
Infrared Spectra ◽  
Functional Group ◽  
Fold Increase ◽  
Polar Compounds ◽  
Signal Averaging ◽  
On Line ◽  
Averaging Techniques

On-line infrared spectra obtained with the Norcon RS-1 gas chromatographic identifier are of sufficient quality for qualitative identification of functional groups, chemical classes, or chemical entities. Identification limits for chemical entities vary between 20 and 200 µg, polar compounds having higher sensitivities. Functional group identifications can be made with correspondingly smaller samples. A 5-fold increase in sensitivity was demonstrated using signal-averaging techniques.

Effect of functional group conformation on the infrared spectra of some gem difunctional phenylethylene derivatives

1969 ◽  
Vol 47 (17) ◽  
pp. 3147-3152 ◽  
Author(s):  
D. J. Currie ◽  
C. E. Lough ◽  
F. K. McClusky ◽  
H. L. Holmes
Keyword(s):  
Absorption Band ◽  
Functional Groups ◽  
Infrared Spectra ◽  
Functional Group ◽  
Plane Deformation ◽  
Carbonyl Groups ◽  
Deformation Bands ◽  
Or Groups ◽  
Out Of Plane ◽  
Stretching Vibrations

Except for the benzalmalononitriles, two functional group stretching vibrations occur in the infrared (i.r.) spectra of the β,β-difunctional-styrenes with similar functional groups. For geometrically homogeneous compounds with dissimilar functional groups only one absorption band occurs for each functional group. The two bands for similar functional groups have been ascribed to S-cis- and S-trans-conformations of the carbonyl groups with respect to the ethylene and variation in the frequencies of each of these oriented carbonyls to rotation of the functional group or groups out of the plane of the ethylene by steric factors.Frequencies for ethylenic C—H out of plane deformation bands for β-monofunctional styrenes accorded with those already assigned to this vibration. A similar assignment could not be made for the difunctional analogues.

scholarly journals Review on stationary phases and coating methods of MEMs gas chromatography columns

2020 ◽  
Vol 39 (1) ◽  
pp. 247-259
Author(s):  
Liu Yang ◽  
Molin Qin ◽  
Junchao Yang ◽  
Genwei Zhang ◽  
Jiana Wei
Keyword(s):  
Gas Chromatography ◽  
Microelectromechanical Systems ◽  
Stationary Phases ◽  
Preparation Methods ◽  
Site Analysis ◽  
Advantages And Disadvantages ◽  
Coating Methods ◽  
On Line ◽  
Inorganic Adsorbents ◽  
Gas Chromatography Columns

Abstract Gas chromatography (GC) is an important and widely used technique for separation and analysis in the field of analytical chemistry. Micro gas chromatography has been developed in response to the requirement for on-line analysis and on-site analysis. At the core of micro gas chromatography, microelectromechanical systems (MEMs) have the advantages of small size and low power consumption. This article introduces the stationary phases of micro columns in recent years, including polymer, carbon materials, silica, gold nanoparticles, inorganic adsorbents and ionic liquids. Preparation techniques ranging from classical coating to unusual sputtering of stationary phases are reviewed. The advantages and disadvantages of different preparation methods are analyzed. The paper introduces the separation characteristics and application progress of MEMs columns and discusses possible developments.

scholarly journals Resilience of Epiphytic Lichens to Combined Effects of Increasing Nitrogen and Solar Radiation

2021 ◽  
Vol 7 (5) ◽  
pp. 333
Author(s):  
Lourdes Morillas ◽  
Javier Roales ◽  
Cristina Cruz ◽  
Silvana Munzi
Keyword(s):  
Global Change ◽  
Solar Radiation ◽  
Functional Groups ◽  
Physiological Response ◽  
Functional Group ◽  
Environmental Drivers ◽  
Combined Effects ◽  
Environmental Stressor ◽  
Comprehensive Understanding ◽  
Direct Sunlight

Lichens are classified into different functional groups depending on their ecological and physiological response to a given environmental stressor. However, knowledge on lichen response to the synergistic effect of multiple environmental factors is extremely scarce, although vital to get a comprehensive understanding of the effects of global change. We exposed six lichen species belonging to different functional groups to the combined effects of two nitrogen (N) doses and direct sunlight involving both high temperatures and ultraviolet (UV) radiation for 58 days. Irrespective of their functional group, all species showed a homogenous response to N with cumulative, detrimental effects and an inability to recover following sunlight, UV exposure. Moreover, solar radiation made a tolerant species more prone to N pollution’s effects. Our results draw attention to the combined effects of global change and other environmental drivers on canopy defoliation and tree death, with consequences for the protection of ecosystems.

Sign in / Sign up

Export Citation Format

Share Document