Referencing strategies and techniques in stable isotope ratio analysis

Stable isotope ratios are reported in the literature in terms of a deviatio n from an international standard (delta -values). The referencing procedure s, however, differ from instrument to instrument and are not consistent bet ween measurement facilities. This paper reviews an attempt to unify the str ategy for referencing isotopic measurements. In particular, emphasis is giv en to the importance of identical treatment of sample and reference materia l ('IT principle'), which should guide all isotope ratio determinations and evaluations. The implementation of the principle in our laboratory, the mo nitoring of our measurement quality, the status of the international scales and reference materials and necessary correction procedures are discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.