Ensuring complete overlapping (coelution) of analyte and internal standard peaks can be critical for eliminating matrix effects in LC–MS/MS analysis.
We assessed a simple method based on recovery for the detection of matrix effects and two alternative methods for the rectification of matrix effects in LC–MS: standard addition and the coeluting internal standard method.
This article describes possible sources of error that may contribute to significant inaccuracy in peptide assay methods: The fi ltration material (cellulose) used in sample clean up and the vial material (glass and plastic) used in LC analysis. This study is based on ?-endorphin but has relevance for most peptide assays.
Likely sources of error are filtration and vial materials.