Mechanism of error caused by isotope‐labeled internal standard: accurate method for simultaneous measurement of vitamin D and pre‐vitamin D by liquid chromatography/tandem mass spectrometry

Abstract

The use of an internal standard with labeling remote from the conjugated area eliminated the error source and gave accurate correction at all of the temperatures investigated. Heating may be used for rapid sample preparation as an alternative to overnight saponification at room temperature. This work not only describes the mechanism of an inaccurate internal standard correction, but also establishes a rapid LC/MS/MS method for simultaneous measurement of vitamin D and pre-vitamin D.