Research Library

The Quill Peptides Research Library is a plain-English reference for the researchers we supply: peptide chemistry fundamentals, laboratory handling procedures, and how to read purity and identity data. Everything here is written for laboratory and research use only — nothing on this page describes or endorses human or veterinary administration of any compound.

Fundamentals

What Are Peptides? Peptide chemistry, how research peptides are synthesized, what purity data means, and what “research use only” actually means. Read Guide → Peptide Glossary An A–Z of the chemistry, analytical and supply terms that appear on certificates of analysis and synthesis paperwork. Read Guide → Research Use Only, Explained What the classification is, what it does not cover, and what it asks of a buyer. A description of how the framing works, not legal advice. Read Guide →

Handling & Storage

How to Reconstitute Peptides Bacteriostatic vs. sterile water, calculating stock-solution concentration, sterile technique, and post-reconstitution storage. Read Guide → Peptide Storage and Handling Lyophilised vs. reconstituted stability, temperature, light, humidity and freeze-thaw — explained as degradation chemistry. Read Guide → Peptide Solubility Guide How net charge and hydrophobicity drive solvent choice, why some sequences need acetic acid or DMSO, and the order of addition that avoids precipitation. Read Guide →

Buying & Quality

How to Choose a Peptide Supplier A framework you can apply to any supplier: what purity figures claim, what a COA proves, batch vs. generic paperwork, and the red flags worth walking away from. Read Guide → How to Read a Peptide COA Every field on a certificate of analysis explained — identity block, lot number, HPLC purity, mass spec confirmation, and the omissions worth noticing. Read Guide → HPLC vs. Mass Spectrometry One measures how much of a sample is a single substance; the other establishes what that substance is. Why purity and identity are separate questions. Read Guide → Peptide Purity vs. Net Peptide Content A 99% purity figure and a 99% content figure are not the same claim. Counter-ions, salt mass and residual water, with the arithmetic worked through. Read Guide →

Compound Guides

BPC-157 vs. TB-500 Sequence, molecular weight, charge state, proline content and counter-ion mass compared. A structural comparison only. Read Guide → CJC-1295 vs. Sermorelin The four substitutions that separate the two, what the DAC linker is chemically, and the mass arithmetic that tells three molecules apart. Read Guide →