Lab Notes

Practical notes on testing, storing, and handling research peptides in the lab. For laboratory research use only.

• How to read a peptide certificate of analysis
  What each line on a peptide certificate of analysis means: identity by mass spec, purity by HPLC, lot numbers, test dates, and the red flags to look for.
• HPLC vs. mass spec: what peptide testing actually measures
  HPLC measures purity and mass spectrometry confirms identity. How each method works, what it can miss, and why a good COA uses both.
• Storing lyophilized peptides: temperature, light, and moisture
  Lab storage guidelines for freeze-dried research peptides: sealed vs. reconstituted, refrigerator vs. freezer, condensation, light, oxidation, and freeze-thaw cycles.
• Bacteriostatic water vs. sterile water in the lab
  The difference between bacteriostatic water and sterile water for reconstituting lyophilized research peptides: benzyl alcohol, multi-use vials, and assay compatibility.
• What “≥99% purity” means, and what it doesn't
  How peptide purity percentages are calculated, what the remaining 1% usually is, the difference between purity and net peptide content, and why the number matters for research.
• Why lot numbers matter for research peptides
  How lot numbers connect a vial to its certificate of analysis, why batch-to-batch variation matters in research, and what to record in your lab notes.