Inter-laboratory Comparison of Stable Carbon and Nitrogen Isotopic Composition Data Using Elemental Analyzer-isotope Ratio Mass Spectrometers

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Research article

Journal of the Korean Society for Environmental Analysis 2018;21(4):229-236.

김정현¹, 강수진², 봉연식³, 박광규⁴, 강태우⁵, 박용세⁶, 김다해¹, 최승현³, 주영지¹, 최보형², 남승일¹, 이상모⁶, 신경훈²

¹한국해양과학기술원 부설 극지연구소
²한양대학교
³한국기초과학지원연구원
⁴한국해양과학기술원
⁵국립환경과학원
⁶서울대학교

Abstract

In this study, inter-laboratory comparison was done using elemental analyzer-isotope ratio mass spectrometers (EA-IRMSs) to determine carbon and nitrogen contents as well as stable carbon and nitrogen isotopic compositions (δ13C and δ15N) of five environmental samples containing lake and marine sediments, higher plant leaves, and fish muscle, and one organic analytical standard (Protein (Casein) Standard OAS). Five national laboratories participated in this comparison study, and each laboratory analyzed all five samples and the analytical standard. Results showed that variations in total organic carbon (TOC) and total nitrogen (TN) contents as well as δ13CTOC and δ15NTN values among the laboratories were large compared to the analytical uncertainties. The results highlighted the inhomogeneity of the test samples and thus, the need to select suitable standard reference materials for future inter-laboratory studies. Further inter-laboratory comparison exercises could promote good measurement practices in the acquisition of stable carbon and nitrogen isotopic composition data.

Key Words: Inter-laboratory comparison, Stable carbon isotope (δ13C), Stable nitrogen isotope (δ15N)