Pyrolysis gas chromatography mass spectrometry analysis of starch-based ion-exchangers

The pyrolysis-gas chromatography-mass spectrometry (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-hydroxypropyltrimethyl-ammonium 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-hydroxymethylfuraldehyde, 3-methoxy-5-methyl-2(5H)-furanone, 1,4-dideoxy-D-glycero-hex-1-en-pyranose-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 analysed material. Only indirect proof of linkage can be concluded from the dramatic decrease of degradation products from starch in the modified starch samples. (C) 1997 Elsevier Science B.V.