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United States Department of Agriculture

Agricultural Research Service

Title: Pyrolysis-Gc-Ms Analysis of Forages: What Happens to the Protein Fractions?

Authors
item Reeves Iii, James
item Francis, Barry

Submitted to: Federation of Analytical Chemistry and Spectroscopy Societies Final Program
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 1997
Publication Date: N/A

Technical Abstract: The objective of this work was to try to improve the results obtained by pyrolysis for the protein fraction of forages. Pyrolysis-GC-MS has been extensively used to analyze the composition of organic materials such as soils, polymers and forages. It has been shown to be very useful in the analysis of forages, particularly for analysis of the lignin fraction. While analysis of carbohydrates is less straight forward than for lignin, the analysis is again extremely useful and informative. Pyrolysis of forages, however, does not produce an abundance of information on the proteins in forages, even for forages containing almost 30% protein by weight. This is a problem and is true despite the fact that pyrolysis of isolated proteins produces an abundance of products. For example, the only products generally reported as originating from the pyrolysis of forages are indole, methylindole, a methylphenol and methanethiol. Unfortunately these products are produced in relatively low amounts and methanethiol is not resolvable from other low molecular weight products such as CO2 and acetic acid, which are produced in large amounts. Recent efforts have demonstrated that NH3 is produced from proteins and can be detected using mass spectrometry, but like methanethiol, it is not resolvable from other low molecular weight products. Efforts with pyrolysis of proteins treated with trimethylammonium hydroxide demonstrated that, like the treatment of lignin and carbohydrates, such treatment results in a different mix of products from that obtained by pyrolysis of untreated proteins. The similar treatment of forages may offer a method for improving the pyrolysis results for proteins in forages.

Last Modified: 7/30/2014
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