Bridge Labs
Purity tells you how much of a sample is the intended compound. It does not tell you which compound that is. Identity confirmation answers the second question: is this the molecule the label says it is?
What an identity check confirms
We use mass spectrometry, which ionises the sample and measures the mass-to-charge ratio of the ions — a direct readout of molecular mass. For peptides, the measured mass is compared with the value calculated from the stated sequence. A match within the method’s tolerance supports the claimed identity; a mismatch flags a different compound, a modification or a substitution. The report states the declared compound, the expected mass and the measured mass side by side.
Why identity matters alongside purity
A chromatography purity result can show a single, clean peak and still describe the wrong substance — purity measures proportion, not identity. Two peptides with similar behaviour can elute at comparable times, so a high purity figure alone does not prove the sample is the intended molecule. Run together, identity confirms what the compound is and purity confirms how much of the sample it accounts for.
To arrange testing, see submit a sample.