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Isotope Ratio Mass Spectrometric Method for the On‐line Determination of Oxygen‐18 in Organic Matter
Author(s) -
Koziet J.
Publication year - 1997
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199701)32:1<103::aid-jms463>3.0.co;2-9
Subject(s) - chemistry , oxygen , organic matter , isotope , isotopes of oxygen , environmental chemistry , radiochemistry , analytical chemistry (journal) , chromatography , organic chemistry , nuclear chemistry , nuclear physics , physics
A method for the on‐line determination of oxygen‐18, at a naturally occurring level, in organic material is presented. After pyrolysis of the samples to form carbon monoxide, which is performed at 1300°C in a vitreous carbon tube, the pyrolysis products are transported by a stream of helium gas. Using an open split, a small part of the effluent is transferred to the ion source of an isotope ratio mass spectrometer. The ratio is obtained from a measurement of the ion current intensities at m / z 30 and 28 ( 12 C 18 O and 12 C 16 O). The method was tested with the secondary water standard GISP (Greenland Ice Sheet Precipitation) and the carbonate standard NBS 19. The values obtained were ‐24.8 ‰ and 27.3 ‰ vs . VSMOW (Vienna Standard Mean Ocean Water) (IAEA reference values are ‐24.8 ‰ and 28.7 ‰ vs . VSMOW). The potential of the method was demonstrated by measuring the 18 O content of samples of beet and cane sucrose and also samples of vanillin extracted from vanilla pods or of synthetic origin. © 1997 by John Wiley & Sons, Ltd.