Trace Metals in Synthetic Peptides: The Impurity HPLC Misses
Why HPLC purity data cannot detect trace metals in synthetic peptides, where elemental impurities come from, and how ICP-MS testing is scoped.
ELSD and CAD: Detecting Compounds UV Cannot See
How ELSD and CAD detect compounds with no UV chromophore, their calibration and mobile phase limits, and how to read a purity figure from each.
What an ELISA Really Measures When You Quantify a Peptide
Explains what an ELISA really measures for peptides, where antibody cross-reactivity and standard curves mislead, and when HPLC is the better tool.
Co-elution in Peptide HPLC: How One Peak Can Hide Two Compounds
How co-elution hides impurities under a peptide’s main HPLC peak, why it always inflates purity, and which checks detect a shared peak.
Residual Solvents in Synthetic Peptides: The Part of the Vial HPLC Cannot See
Residual solvents in synthetic peptides: where acetonitrile and DMF come from, why HPLC misses them, and how headspace GC measures them.
When a Peptide Assay Result Will Not Reproduce: Tracing the Sources of Disagreement
Why peptide assay results fail to reproduce between labs: handling losses, net content, cell models and serum, plus what to record so work can be repeated.
HPLC Area Percentage: What a Peptide Purity Figure Actually Counts
What an HPLC area percentage measures for peptides, what it leaves out, and why 99% by HPLC is not 99% peptide by weight. A guide for analysts.
Moving an HPLC Method to a Second Laboratory: What Has to Travel With It
Moving an HPLC method between laboratories: why a copied peptide purity method can read higher, and how suitability criteria show it still works.
Reference Standards and Traceability in Peptide Analysis
Relative versus absolute peptide results, what reference standards and metrological traceability mean, and why HPLC purity is not a content value.
Monoisotopic vs Average Mass: Avoiding False Peptide Mass Mismatches
Monoisotopic and average peptide masses differ by up to several daltons. Learn why, which one your instrument reports, and how to avoid false mismatches.