In summary, these examples show that the combination of an ICP/Quad-filter/CCT/MC-MS instrument can significantly improve specificity for highly precise and accurate isotope abundance measurements of interfered sample material. As such it can greatly improve the ability for direct sample analysis with, for instance, laser ablation and without extended chemical preparation. Selecting certain mass windows covering at least the isotopes to be studied followed by a collision cell for fragmentation and/or charge exchange and/or mass shift reactions allow for significantly improved specificity for isotope ratio analysis.

As used herein, including in the claims, singular forms of terms are to be construed as also including the plural form and vice versa, unless the context indicates otherwise. Thus, it should be noted that as used herein, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

Throughout the description and claims, the terms “comprise”, “including”, “having”, and “contain” and their variations should be understood as meaning “including but not limited to”, and are not intended to exclude other components.

The present invention also covers the exact terms, features, values and ranges etc. in case these terms, features, values and ranges etc. are used in conjunction with terms such as about, around, generally, substantially, essentially, at least etc. (i.e., “about 3” shall also cover exactly 3 or “substantially constant” shall also cover exactly constant).