Peptides are shipped as a lyophilized powder and should be stored at -20°C upon receipt. Allow peptides to warm to room temperature before opening the vial to prevent condensation of atmospheric moisture onto the peptide, making it easier to handle and weigh. It is recommended to dissolve only the required amount into a buffer. The remainder of the stock should be stored dry at -20°C. Storage in buffer is not recommended. Peptides in solution are only stable for up to one week when stored at 4°C. If peptides are to be used frequently, solubilize and aliquot, then store frozen at -20°C to avoid freeze-thaw cycles. Typically the peptide will remain stable for several months. For short term storage (up to 2 months), freeze at -20°C; for long term storage -80°C is recommended.
Ideally, vials for peptide storage should be high-density, polypropylene tubes, airtight, well sealed with a screw cap with an O-ring. Avoid storing or making up peptide solutions in polystyrene containers as they adsorb peptide material to their surface.
Peptides containing Cys, Trp or Met are susceptible to oxidation. It is advisable to blanket the peptide with argon or nitrogen when the vial is opened. Buffers used to dissolve these peptides should be degassed. These peptides have limited stability; long-term storage is not recommended.
Hygroscopic peptides containing several charged residues (D, E, K, R, H) may take up water when exposed to air. To prevent this, argon or nitrogen may be used to blanket the peptide when the vial is opened. If inert gases are unavailable, then storage in a desiccator is a viable alternative. Before use, bring samples to room temperature in a desiccator.
thinkpeptides is a brand of ProImmune