HPLC vs. Mass Spectrometry: What Each Method Actually Tells You

HPLC and mass spectrometry answer different questions, and a complete analytical record uses both.

High-performance liquid chromatography answers: how much of the sample is the target compound? The instrument separates a dissolved sample across a column; compounds elute at characteristic times and register as peaks. The target peak's share of total peak area is the reported purity.

Mass spectrometry answers: is the target compound actually what it claims to be? By measuring the mass-to-charge ratio of ionized molecules, MS confirms the molecular weight of the principal component against the theoretical weight of the stated sequence.

A COA reporting only HPLC purity tells you how clean the material is, but not what it is. A COA reporting only MS confirms identity but says nothing about purity. When reviewing documentation, look for both.

This is why Vial Drop Labs documentation lists the analytical method alongside each published result, and why product pages link to the current lot's full record rather than a single number.