Bacteriostatic water is sterile water containing a small amount of preservative that limits microbial growth, which makes it well suited to reconstituting peptides whose solutions will be stored and sampled over time. This guide explains it.
What is in it?
It is water for laboratory use with a low concentration of a preservative (commonly benzyl alcohol). The preservative does not sterilize the solution but slows the growth of microorganisms, hence "bacteriostatic."
How it differs from sterile water
Sterile water is free of microorganisms at the moment it is sealed but has no ongoing protection once opened and sampled. Bacteriostatic water's preservative gives a solution some resistance to contamination over repeated use.
When to use it
Use bacteriostatic water when a reconstituted peptide solution will be kept and drawn from more than once. For a single-use preparation, sterile water can suffice. For the complete lab guide to composition, vial sizes, stock-concentration math and storage, see bacteriostatic water for peptides.
Handling
Store cold, keep the vial sealed between uses, and follow the peptide's solubility guidance; if the peptide is basic and does not dissolve cleanly, a dilute acetic acid solution may be needed instead.
Related research guides
- Bacteriostatic water for peptides: the full lab guide
- How to reconstitute lyophilized peptides
- Choosing a reconstitution solvent
- Why some peptides won't dissolve
Research-use note
All materials discussed are supplied for in vitro laboratory research use only.
