Understanding HPLC & Mass Spectrometry Purity Analysis in Research Compounds

Analytical Validation of Research Peptides

High-quality peptide synthesis requires strict verification to distinguish authentic full-length target peptides from deletion sequences, truncated fragments, and protecting-group adducts.

Reverse-Phase HPLC (RP-HPLC)

RP-HPLC separates peptide molecules based on their hydrophobic interactions with a C18 bonded stationary silica phase under high pressure:

• Chromatogram Retention Time: Each peptide elutes at a characteristic retention time based on its amino acid hydrophobicity gradient (acetonitrile/water with 0.1% TFA).
• Area Under the Curve (AUC): Purity is quantified by integrating the main absorption peak against minor background noise peaks at UV wavelength 214 nm or 220 nm (the peptide bond absorption spectrum).
• Target Standard: USA Peptide Depot guarantees a minimum threshold of >99.0% chromatographic purity across all research lots.

Electrospray Ionization Mass Spectrometry (ESI-MS)

While HPLC confirms chromatographic homogeneity, Mass Spectrometry confirms the exact chemical identity and molecular formula weight:

• Mass-to-Charge Ratio (m/z): Measures protonated molecular ions ([M+H]^+), ([M+2H]^{2+}), and ([M+3H]^{3+}).
• Deconvolution: Reconstructs the exact observed monoisotopic molecular weight and validates it within $pm 0.5$ Da of theoretical molecular weight.