Stable isotopically labeled internal standards in quantitative bioanalysis using liquid chromatography/mass spectrometry: necessity or not?
Article first published online: 12 JAN 2005
Copyright © 2005 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 19, Issue 3, pages 401–407, 15 February 2005
How to Cite
Stokvis, E., Rosing, H. and Beijnen, J. H. (2005), Stable isotopically labeled internal standards in quantitative bioanalysis using liquid chromatography/mass spectrometry: necessity or not?. Rapid Commun. Mass Spectrom., 19: 401–407. doi: 10.1002/rcm.1790
- Issue published online: 12 JAN 2005
- Article first published online: 12 JAN 2005
- Manuscript Revised: 23 NOV 2004
- Manuscript Accepted: 23 NOV 2004
- Manuscript Received: 4 SEP 2004
It appears to be a general belief that stable isotopically labeled (SIL) internal standards yield better assay performance results for quantitative bioanalytical liquid chromatography/mass spectrometry (LC/MS) assays than does any other internal standard. In this article we describe our experiences with structural analogues and SIL internal standards and their merits and demerits. SIL internal standards are the first choice, but deuterium-labeled compounds may demonstrate unexpected behavior, such as different retention times or recoveries, than the analyte. In addition, a SIL internal standard with identical chemical properties as the analyte may cover up assay problems with stability, recovery, and ion suppression. Since SIL internal standards are not always available or are very expensive, structural analogues can be used, however, with consideration of several issues, which are usually displayed during method validation. Copyright © 2005 John Wiley & Sons, Ltd.