HPLC purity
High-performance liquid chromatography shows how much of a peptide sample is the intended molecule. It is one of the measurements we are building our models on, so it is worth knowing what it says and what it does not.
Measured for every batch in our loop
Summary
Every batch in our loop is analysed by HPLC in an independent laboratory. The method separates the components of a sample and measures each of them, so the result describes the batch itself rather than a specification on paper.
How HPLC works
A small amount of the dissolved peptide is pumped at high pressure through a column packed with very fine particles. Different molecules interact with the column material to different degrees and leave it at different times. A detector at the end, usually measuring UV absorbance, records each component as a peak.
For peptides, reversed-phase HPLC is the standard approach. The column material is water-repellent, and a gradient from water to an organic solvent releases the molecules one after another, according to how hydrophobic they are.
Reading the chromatogram
The result is a chromatogram: signal over time. The largest peak is normally the target peptide. Smaller peaks are related substances, for example shorter sequences from incomplete synthesis steps or modified forms of the peptide.
Purity is calculated as the area of the main peak divided by the total area of all peaks. It is a relative measure: it describes how clean the sample is, not how much peptide a vial contains.
What purity does not tell you
HPLC purity does not confirm identity on its own: a peak shows that something is there, not which molecule it is. Identity is confirmed with other methods, such as mass spectrometry. Purity also says nothing about bacterial contamination, which is why every batch is tested for endotoxins as well.
From chromatogram to data
A chromatogram holds more than a single number: the position, shape and size of every peak. We are building tools that keep chromatograms as structured data, so each batch can be compared with earlier ones and with the design it came from. This is the kind of data our models are meant to learn from.
Working on peptides and data?
We are looking for research, data and laboratory partners who want to build the loop with us. Tell us what you are working on.
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