Mass spectroscopy aromatic compound

Air Monitoring. The atmosphere in work areas is monitored for worker safety. Volatile amines and related compounds can be detected at low concentrations in the air by a number of methods. Suitable methods include chemical, chromatographic, and spectroscopic techniques. For example, the NIOSH Manual of Analytical Methods has methods based on gas chromatography which are suitable for common aromatic and aHphatic amines as well as ethanolamines (67). Aromatic amines which diazotize readily can also be detected photometrically using a treated paper which changes color (68). Other methods based on infrared spectroscopy (69) and mass spectroscopy (70) have also been reported. 

Similar studies were carried out with benzoic acid on porous palladium electrodes [150]. The objective of this work was to investigate the adsorption processes and the reactivity of benzoic acid on different noble metals, in order to compare these results with those obtained for related aromatic compounds. On-line mass spectroscopy analysis of volatile products revealed that the adsorption of benzoic acid is irreversible at platinum while it is mainly reversible on palladium. Accordingly, different catalytic activity of platinum and palladium was found in the electrooxidation. 

The meta photocycloaddition of cis-cyclooctene to benzene was one of the first examples of this reaction reported, and the addition of this cycloalkene to low molecular weight polystyrene and mono- and di-aromatic model-compounds has now been described. The results were analysed by mass spectroscopy, and it was reptorted that for polymers having up to six styrene units, more than one phenyl group in each chain had reacted. In the 2 1... 

The presence of unsymmetrical dialkyl ditcllurium and unsymmetrical diaryl ditellurium" compounds in solution was confirmed by Te-NMR spectroscopy H-NMR spectroscopy , and mass spectroscopy . Cyclohexyl methyl ditellurium was claimed to have been isolated from a reaction mixture obtained by sequential addition of cyclohexyl bromide and methyl iodide to a solution of tetratelluride anions in dimethylformamide . The chromophoric Te —Te group in the aliphatic and aromatic ditellurium compounds imparts a characteristic orange to red color caused by an absorption maximum at approximately 400 nm. Most of the aromatic ditellurium derivatives are stable as solids toward atmospheric agents, but oxidize slowly when dissolved. The short-chain aliphatic ditellurium compounds are distillable red liquids having an obnoxious odor that clings to skin and clothes. Ditellurium compounds with more than ten carbon atoms in each aliphatic group are low melting solids that can be handled in air. 

In this study the USBM-API separation procedure was modified slightly. Monoaromatic and diaromatic compound types were eluted with specific solvents from an adsorption column. A three- to four-ring aromatic fraction was also desorbed with a stronger eluant. These fractions were separated on the basis of the carbon number of alkyl substituents by GPC. The subfractions obtained from LC and GPC separations were analyzed by mass spectroscopy. This technique provides a method of determining the chemical structure of coal liquids, which is complementary to NMR techniques (9). 

There is indirect evidence for the presence of nitrogen ring systems in coal— the following compounds have been identified by mass spectroscopy as being present in coal tar pitch pyridines, pyrroles, quinolines, azapyrenes, benzacridines, dibenzacridines, and substituted carbazoles. Allowances must be made for any structural alterations during the thermal production of the pitch as well as for aromatization of any hydroaromatic ring systems. 

The evolved gas analyses were conducted on FTIR and mass spectroscopy (MS) devices, coupled to the TG apparatus. The main volatile compounds released below 350 °C were carbon dioxide and water vapours, which increased during the whole thermal decomposition process. Alcohol traces and aromatic structured compounds were also identified. Volatile structures containing carbonyl groups were found in the gaseous mixture at temperature values above 350 °C. Ammonia evolvement was also found in the gaseous mixture. The MS spectra were in good correlation with the findings from the FTIR spectra data. 

Ephedra spp. roots are known as major source of ephedrine and derivatives alkaloids, but this plant species also contains an imidazole derivative, feruloylhistamine (12), which was identified in methanolic extract of the drug in 1983 [19, 20]. After column chromatography and crystallization procedures, feruloylhistamine was characterized by and NMR and mass spectroscopy. A molecular ion peak was observed at miz 287 consistent to a C15H17N3O3 fragment, and the NMR spectrum revealed signals for aliphatic and aromatic carbons and also one carbonyl group. The synthetic derivative was also obtained and afforded the same physical data as the natural compound [19]. 

Some aromatic amines resulting from the reduction of azo dyes have been identified by FTIR (Franciscon et al. 2009 Pielesz 1999). However, FTIR by itself is not always sufficient, so Mass spectroscopy. Gas and/or Liquid chromatography are techniques currently being used as complementary ones for compounds identification. 

The QCM is a well-established piezoelectric mass transducer which can be used to measure mass changes lower than those of a nanogram order. It was reported that the (3-CD/T102 film imprinted with bisphenol A was prepared for the specific detection of bisphenol by QCM and cyclic surface-polarization impedance (cSPI) [67]. The thin y-CD/T102 film with a QCM transducer was used for selective detection of nitro aromatic compounds [68]. The detection was carried out via cyclic surface-polarization impedance spectroscopy. It was also established that (3-CD may be used for functionalization of the mesoporous silica film in order to improve the sensing of gases such as benzene and ethanol by QCM [69]. 

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