Purity Says How Much, Identity Says What: Training New Laboratory Assistants to Read Both
A new laboratory assistant usually arrives with a sensible instinct: trust the number. The number in question is the purity percentage, and it is hard to miss. Research Sciences publishes ≥99% Verified Purity on its homepage, and its FAQs describe peptides typically supplied at ≥99% purity by HPLC, with the exact figure stated on the batch CoA. That headline is a useful starting point, but it is not a substitute for identity testing, and a training programme that treats it as one will produce assistants who can quote a figure without being able to defend it.
Purity and identity answer different questions. A purity percentage describes the proportion of signal attributed to the target under a specific method — column, gradient, wavelength, integration parameters — and it can shift when the...