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Cryoflow: Cryofocusing Nanomole Amounts of CO 2 , N 2 , and SO 2 from an Elemental Analyzer for Stable Isotopic Analysis
Author(s) -
Fry Brian,
Garritt Robert,
Tholke Kris,
Neill Christopher,
Michener Robert H.,
Mersch F. J.,
Brand Willi
Publication year - 1996
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/(sici)1097-0231(19960610)10:8<953::aid-rcm534>3.0.co;2-0
Subject(s) - chemistry , spectrum analyzer , elemental analysis , chromatography , analytical chemistry (journal) , inorganic chemistry , electrical engineering , engineering
A manual "cryoflow' system is described for measuring C, N and S isotopic compositions of small gas samples in the 10–1000 nmol range. Using a continuous flow system with helium as the carrier gas, sample gases are injected or produced via combustion in an elemental analyzer, purified, separated and collected in separate traps with cryogens, then degassed into a slowly flowing helium stream (1–4 mL/min) for measurement with an isotope rato mass spectrometer. Blanks associated with combustion of organics in an elemental analyzer were 5–20 nmol for N and C, and not detectable for S, so that samples of >50 nmol C, N or S could be routinely analyzed with a precision of better than 0.3‰ after blank correction. In some cases, slow degassing of sample gases from traps over several minutes gave broad, low‐amplitude peaks that yielded high‐precision measurements (e.g., <0.05‰ δ 13 C differences between replicates). Work with this manual prototype showed that it is possible to routinely obtain high precision isotope measurements for C, N and S isotopes from the same small sample.