Two methods, different information
Chromatography separates components under a specified method. Mass spectrometry measures mass-to-charge signals. They can be combined in one workflow, but their results are not interchangeable. Start by defining whether the question concerns separation, identity, assay or an impurity.
A concrete research example
In the 2012 TB-500 characterization paper, high-performance liquid chromatography and high-resolution mass spectrometry were used to identify an acetylated thymosin beta-4 fragment. It is a useful example of complementary analytical tools being applied to a specific material.
Why a percentage is not the complete report
A reported chromatographic percentage depends on what was measured and how the method was applied. Ask for the method, result definition and supporting records before comparing percentages across suppliers. ICH Q2(R2) provides a framework for evaluating analytical procedures against their intended purpose.
Ask the laboratory these questions
- What question was the method validated to answer?
- How was the target separated from relevant components?
- Which result supports the stated identity?
- What limitations accompany the reported measurement?
Read both reports together
Review sample identifiers and batch numbers before combining results. An identity result for one sample and a purity report for another should not be treated as a matched analytical package. Follow up with the laboratory when results or report descriptions appear inconsistent.