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ARS Home » Research » Publications at this Location » Publication #83772
Title: PY-GC-MS ANALYSIS OF STARCH-BASED ION-EXCHANGERS

Author
item SIMKOVIC, IVAN - SLOVAK ACADEMY OF SCIENCE
item Reeves Iii, James

Submitted to: Journal of Analytical & Applied Pyrolysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Modified carbohydrates, such as starch, can be used for a variety of purposes, such as flame retardants and paper additives, but information is often required on their composition before determination of their usefulness can be made. Pyrolysis is a procedure in which materials are heated in an inert atmosphere (No oxygen present). The heat causes the material to break down into simpler compounds whose composition depends on the starting materials. When connected to instruments capable of separating the compounds produced (gas/chromatography or GC) and then to an instrument capable of identifying the separated compounds (mass/spectrometry or MS), the procedure can be used to rapidly provide information on the composition of various materials. Pyrolysis was carried out on a variety of modified starches to determine its usefulness in measuring their composition. The results showed differences in the composition of degradation products. The pyrolysis of unmodified starch produced predominantly products typical found when pyrolyzing carbohydrates,such as cellulose. These products were formed to a much lower extent by pyrolysis of starch derivatives and were not formed from samples prepared in the absence of starch. However, the exact nature of the changes induced in the modified starches could not be proved by this method. Only indirect proof of changes induced could be concluded from the dramatic decrease of degradation products from starch in the modified starch samples.

Technical Abstract: The PY-GC-MS analysis of ion-exchangers prepared from starch by crosslinking with epichlorohydrin (E) in the presence of NaOH and water, with or without NH4OH and 3-chloro-2 hydro- xypropyltrimethylammonium chloride (CHMAC) was performed. The data were compared with results run on polymers formed from E, NH4OH and CHMAC in the absence of starch. The total ion chromatograms showed differences in the composition of degradation products. The pyrolysis of unmodified starch produced predominantly 2-furaldehyde, 3,5-dihydroxy-2-methyl-4H-pyran-4-one, 5-hydroxy-methyl- furaldehyde,3-methoxy-5-methyl-2(5H)-furanone, 1,4-dideoxy-D-glycerohex 1-enopyranos-3-ulose,and levoglucosan. These products were formed to a much lower extent by pyrolysis of starch derivatives and were not formed from samples prepared in the absence of starch. However,the chemical linkage of the poly(hydroxypropyl) matrix to starch or to the quaternary ammonium groups could not be proved by this method because none of the identified products had this type of linkage or indicates the linkage in analyzed material. Only indirect proof of linkage can be concluded from the dramatic decrease of degradiation products from starch in the modified starch samples.