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Rapid online equilibration method to determine the D/H ratios of non‐exchangeable hydrogen in cellulose
Author(s) -
Filot Marc S.,
Leuenberger Markus,
Pazdur Anna,
Boettger Tatjana
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2743
Subject(s) - chemistry , cellulose , hydrogen , nitration , isotope ratio mass spectrometry , deuterium , analytical chemistry (journal) , fractionation , mass spectrometry , chromatography , organic chemistry , physics , quantum mechanics
An improved method for the determination of deuterium‐to‐hydrogen (D/H) ratios of non‐exchangeable hydrogen in cellulose is presented. The method is based on the equilibration reaction of the hydroxyl hydrogen of cellulose and water vapour of known isotopic composition. The equilibrated cellulose is pyrolysed and the total D/H ratio determined by subsequent online isotope ratio mass spectrometry (IRMS). With a mass balance system the D/H ratio of non‐exchangeable hydrogen is recalculated after an empirical calibration has been performed, yielding a mean exchangeability of 0.239 and an equilibrium fractionation factor of 1.082 between the hydroxyl hydrogen of cellulose and water hydrogen at 110°C. Equilibration takes 10 min per sample. Results obtained by this online equilibration method agree very well with values obtained by the nitration technique (R 2 = 0.941). The uncertainty of the equilibration method is ±4‰ resulting from a single standard deviation of ±2.8‰ for the equilibration determined by standard cellulose and 2.8‰ from the variable exchangeability of the hydroxyl hydrogen in cellulose due to crystalline areas. The latter uncertainty may be lowered by minimising the crystallinity of the cellulose. Advantages of this new technique are (i) the considerably reduced sample amount required (as low as 0.2 mg, ideally 0.5 mg compared with 20 mg for the conventional nitration technique); (ii) an approximately 100‐fold reduced process time; and (iii) no need for the hazardous chemicals used in the nitration technique. Copyright © 2006 John Wiley & Sons, Ltd.