Volatile compounds generated from

Gamliel A, Stapleton JJ (1997) Improvement of soil solarization by volatile compounds generated from organic amendments. Phytoparasitica 25(S) 315-385 Gamliel A, Hadar E, Katan J (1989) Soil solarization to improve yield of gypsophila in monoculture systems. Acta Hortic. (ISHS) 255 131-138... 

Chen J, Wang M, Ho CT (1998) Volatile compounds generated from the thermal degradation ofN-acetylglucosamine. J Agric Food Chem 46, 3207-3209. 

Table I. Volatile Compounds Generated from the Thermal Reaction of WGH, DWGH and AWGH with Glucose...

Volatile Compounds Generated from Thermal Interactions of Inosine-5 -monophosphate and Alliin or DeoxyaUiin... 

The gas chromatographic profiles of the volatile compounds generated from the model reaction systems are shown in Fig. 1. The identification and quantification of the volatile compounds generated from the model systems of IMP and alliin as well as IMP and deoxyalliin are listed in Tables II and III, respectively. As shown in Fig. 1 (C), in the absence of alliin or deoxyalliin, thermal degradation of IMP produced only a few trace components. 

The comparison of the yields of volatile compounds generated from the model systems is shown in Table IV. The major differences between these two systems were that the formation of thiazoles was favorable in the IMP and alliin system and the IMP and deoxyalliin system favored the formation of allylthio-containing compounds. 

Table IV. Comparison of the Yields of Volatile Compounds Generated from IMP + Alliin, and BMP + Deoxyalliin Model Reaction Systems...

Yu, T.H. Ho, C.-T. 1995. Volatile compounds generated from thermal reaction of methionine and methionine sulfoxide with or without glucose. J. Agric. Food Chem. 1995, 43, 1641—1646. 

These results indicate that the production of nearly all volatile compounds generated from wounding of whole plant tissues in addition to those generated via LOX action is enzymatically controlled. 

The primary use of DEMS is for the determinahon of vola-hle hydrophobic compounds generated from an electrode leachon. It is based on an uncannily simple principle When a porous hydrophobic membrane is placed between an electrochemical cell and a diffeienhally pumped mass spectrometer, all species that are simultaneously hydrophobic and volatile will be drawn out from the cell and directed into the mass analyzer where they can be identified based on mass-to-charge rahos and/or fragmentahon patterns. 

In addition to comonomers, nylons are frequently used in blends. The pyrolysis of blends typically shows little interaction between the compounds generated from the individual blend components. However, a study on the co-pyrolysis of several polyamides in the presence of PVC showed interactions [40]. The study was done on nylon-12, nylon-6,6 and poly(1,4-phenylene terephthalamide) (Kevlar) in the presence of poly(vinyl chloride). Polyamide-PVC mixtures (typical mass ratio 1 1) were pyrolyzed at 700 and 900°C. It was found that the presence of PVC promoted the hydrol ic decomposition routes of amide groups and volatile nitrile formation from all examined polyamides due to the hydrogen chloride eliminated from PVC under pyrolysis. In the presence of PVC, an elevated yield of alkenenitriles was observed from nylon-12. For Kevlar in the presence of PVC, it was noticed the evolution of benzeneamine, benzoic acid, benzenenitrile and benzeneisocyanate. At 900°C in the presence of PVC, an enhanced evolution of HCN from nylon-12 and nylon-6,6 was noticed. 

The purpose of this presentation is to review procedures for the analysis of volatile compounds generated through biological processes. Numerous techniques have been proposed to separate the volatile chemicals from the nonvolatile materials and water, and to concentrate them. After sample preparation, the complex aroma sample can be separated into its individual components by high resolution gas chromatography and the aroma chemicals then structurally identified by spectral techniques. 

Chun H.K. and Ho C.T. (1997) Volatile N-containing compounds generated from Maillard reactions under simulated deep-fat frying conditions. J. Food Lipids 4 (4), 239—44. 

As shown in Table II, some volatile compounds identified from the thermal interaction of IMP and alliin were derived from the thermal degradation of alliin (II, 13), and the others were generated from the interactions of IMP and alliin. 

Static headspace GC/MS. The partitioning of volatile and semivolatile compounds between two phases in a sealed container. An aliquot of the headspace gas generated is injected onto a gas chromatographic column. This is followed by mass spectrometric analysis of compounds eluting from the gas chromatograph. 

About 100 gal of process wastewater is typically generated from 1 t of coke produced.15 These wastewaters from byproduct coke making contain high levels of oil and grease, ammonia nitrogen, sulfides, cyanides, thiocyanates, phenols, benzenes, toluene, xylene, other aromatic volatile components, and polynuclear aromatic compounds. They may also contain toxic metals such as antimony, arsenic, selenium, and zinc. Water-to-air transfer of pollutants may take place due to the escape of volatile pollutants from open equalization and storage tanks and other wastewater treatment systems in the plant. 

The instrument used to generate the data shown in Figures 1 and 2 (LECO Pegasus III GC x GC-ToF-MS) has a modulator at the end of the first 30 mx 0.25 mm non-polar column (HP-5MS, 0.25 pm film thickness). As compounds elute from this column, the modulator concentrates them over a short period to focus them and then sends them down the second, shorter and narrower 2 m x 0.10 mm, polar column (BPX-50, 0.10 pm film thickness) situated in its own oven compartment within the main oven. This operation is repeated throughout the analytical run. Having the two columns coupled in this way allows compounds to be separated by volatility on the first analytical column and by polarity on the second column. Hence for complex mixtures, peaks with a similar (or identical) retention on the first column can be separated by the second column. Non-polar compounds emerge before polar components. 

Relatively little work has been done on the flash photolysis of gas phase metal carbonyls, partly because of the low volatility of many of the compounds. Early work by Callear (41,42) provided some evidence for Ni(CO)3 generated from Ni(CO)4 in the gas phase (41) and Fe atoms produced from Fe(CO)5 (42). This latter process has even been used as the basis of an Fe atom laser (43). More recently Breckenridge and Sinai (44) studied the flash photolysis of Cr(CO)6. Their results, interpreted largely on the basis of data from matrix isolation experiments, were in broad agreement with Kelly and Bonneau s solution work (JJ). In particular, they found no evidence for loss of more than one CO group [Eqs. (4) and (5)]. 

---