HPLC Method Questions to Ask a Peptide Supplier
A purity percentage without a method is an assertion. The questions that separate a supplier who ran an analysis from one who bought a number.
Bacteriostatic Water vs Sterile Water: What the Labels Mean
Bacteriostatic water is sterile water with 0.9% benzyl alcohol; sterile water has no additive. What each label means and where it matters.
Research Peptide Glossary: Terms Every Buyer Should Know
Plain definitions of the terms that appear on specifications and certificates, written for people evaluating a supplier rather than writing a synthesis.
What Is a Lyophilized Peptide? Reading the Powder in the Vial
The appearance of a lyophilized peptide is weak evidence about quality and strong evidence about process. Here is how to read it, and how not to over-read it.
TFA vs Acetate: Why Peptide Counter-Ions Change the Numbers
The counter-ion on a synthetic peptide is not a footnote. It contributes mass, it can affect assays, and it belongs in your notes alongside the sequence.
Why Two Suppliers Report Different Purity for the Same Peptide
Two honest laboratories can analyse the same peptide and publish different numbers. The gap is usually method rather than misconduct.
Mass Spectrometry for Peptide Identity: What It Proves
A matching mass is strong evidence of identity and weak evidence of purity. Knowing the difference stops a mass spectrum doing the wrong job.
Common Peptide Synthesis Impurities and How to Spot Them
Synthetic peptides do not fail cleanly. The characteristic by-products of SPPS are near-relatives of the target, which is exactly why they are hard to see.
Reverse-Phase HPLC for Peptide Purity: How It Works
Why RP-HPLC became the default method for assessing synthetic peptide purity, where the method is strong, and where it is genuinely blind.
What Should a Peptide Certificate of Analysis Contain?
Most documents sold as a COA are a purity number on letterhead. Here is what a genuinely useful analytical record contains, and what its absence tells you.