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Simultaneous δ 15 N, δ 13 C and δ 34 S measurements of low‐biomass samples using a technically advanced high sensitivity elemental analyzer connected to an isotope ratio mass spectrometer
Author(s) -
Hansen T.,
Burmeister A.,
Sommer U.
Publication year - 2009
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.4267
Subject(s) - chemistry , isotope , analytical chemistry (journal) , isotope analysis , stable isotope ratio , sulfur , tracer , mass spectrometry , natural abundance , isotopes of carbon , radiochemistry , carbon fibers , environmental chemistry , chromatography , total organic carbon , nuclear physics , ecology , physics , materials science , organic chemistry , composite number , composite material , biology
Conventional simultaneous CNS stable isotope abundance measurements of solid samples usually require high sample amounts, up to 1 mg carbon, to achieve exact analytical results. This rarely used application is often impaired by high C:S element ratios when organic samples are analyzed and problems such as incomplete conversion into sulphur dioxide occur during analysis. We introduce, as a technical innovation, a high sensitivity elemental analyzer coupled to a conventional isotope ratio mass spectrometer, with which CNS‐stable isotope ratios can be determined simultaneously in samples with low carbon content (<40 µg C corresponding to ∼100 µg dry weight). The system includes downsized reactors, a temperature program‐controlled gas chromatography (GC) column and a cryogenic trap to collect small amounts of sulphur dioxide. This modified application allows for highly sensitive measurements in a fully automated operation with standard deviations better than ±0.47‰ for δ 15 N and δ 34 S and ±0.12‰ for δ 13 C (n = 127). Samples collected from one sampling site in a Baltic fjord within a short time period were measured with the new system to get a first impression of triple stable isotope signatures. The results confirm the potential of using δ 34 S as a stable isotope tracer in combination with δ 15 N and δ 13 C measurements to improve discrimination of food sources in aquatic food webs. Copyright © 2009 John Wiley & Sons, Ltd.