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A reactor for high‐temperature pyrolysis and oxygen isotopic analysis of cellulose via induction heating
Author(s) -
Evans Michael N.
Publication year - 2008
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.3603
Subject(s) - chemistry , analytical chemistry (journal) , pyrolysis , cellulose , blank , oxygen , chromatography , materials science , composite material , organic chemistry
A reactor for converting cellulose into carbon monoxide for subsequent oxygen isotopic analysis via continuous flow isotope ratio mass spectrometry is described. The system employs an induction heater to produce temperatures ≥1500°C within a molybdenum foil crucible positioned by boron nitride (BN) spacers within a quartz outer sleeve. For samples of a homogeneous working standard cellulose between 300 and 400 µg in size, the blank/signal ratio is <5%, and the long‐term precision is 0.30‰ (N = 232). For samples of 30 to 100 µg in size, a gas pressure sintered silicon nitride (Si 3 N 4 ) outer sleeve replaces the quartz sleeve, the BN spacers are not used, and 6.0‐grade carrier He must be used to minimize the blank signal. With these modifications a blank/sample ratio of <5% and long‐term precision of 0.30‰ (N = 144) are obtained. These results are similar to those achieved using standard high‐temperature furnaces, but the reactor is simpler to pack, the system is more economical to run, and samples as small as 30 µg cellulose may be measured. For both reactors memory is significant in the subsequent sample and is believed to be due to exchange with reactor oxygen at temperatures above 1000°C. Further applications might include online preparation of other materials requiring temperatures of 1500–2600°C. Copyright © 2008 John Wiley & Sons, Ltd.