A novel high‐temperature combustion interface for compound‐specific stable isotope analysis of carbon and nitrogen via high‐performance liquid chromatography/isotope ratio mass spectrometry. (29th February 2016)

• Record Type: Journal Article
• Authors: Federherr, E.; Willach, S.; Roos, N.; Lange, L.; Molt, K.; Schmidt, T. C.
• Is Part Of: Rapid communications in mass spectrometry. Volume 30:Number 7(2016)
• Page Start: 944
• Page End: 952
• Publication Date: 2016-02-29
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.7524
• Languages: English
• ISSNs: 0951-4198

Abstract

Abstract: Rationale: In aqueous samples compound‐specific stable isotope analysis (CSIA) plays an important role. No direct method (without sample preparation) for stable nitrogen isotope analysis ( δ 15 N SIA) of non‐volatile compounds is known yet. The development of a novel HPLC/IRMS interface based on high‐temperature combustion (HTC) for both δ 13 C and δ 15 N CSIA and its proof of principle are described in this study. Methods: To hyphenate high‐performance liquid chromatography (HPLC) with isotope ratio mass spectrometry (IRMS) a modified high‐temperature combustion total organic carbon analyzer (HTC TOC) was used. A system to handle a continuously large amount of water (three‐step drying system), favorable carrier and reaction gas mix and flow, an efficient high‐temperature‐based oxidation and subsequent reduction system and a collimated beam transfer system were the main requirements to achieve the necessary performance. Results: The proof of principle with caffeine solutions of the system succeeded. In this initial testing, both δ 13 C and δ 15 N values of tested compounds were determined with precision and trueness of ≤0.5 ‰. Further tests resulted in lower working limit values of 3.5 μgC for δ 13 C SIA and 20 μgN for δ 15 N SIA, considering an accuracy of ±0.5 ‰ as acceptable. Conclusions: The development of a novel HPLC/IRMS interface resulted in the first system reported to be suitable for both δ 13 C and δ 15 N direct CSIA of non‐volatile compounds. This highly efficient system will probably open up new possibilities in SIA‐based research fields. Copyright © 2016 John Wiley & Sons, Ltd.