Bacteriostatic Water
Laboratory Supplies
Available sizes: 3 ml, 10 ml
Sterile water with 0.9% benzyl alcohol
Bacteriostatic water is sterile water to which benzyl alcohol has been added at 0.9%. Benzyl alcohol is bacteriostatic rather than bactericidal — it suppresses bacterial multiplication rather than sterilising the contents — and that is precisely the property that matters for a multi-use vial.
Sterile water for injection has no preservative and is single-use for that reason: once the stopper is pierced, nothing prevents growth in what remains. The 0.9% addition is what permits repeated withdrawal from one vial over a working period.
When it is the right choice
It is the standard solvent for lyophilised peptides, and the right default unless something specific argues otherwise:
Reconstituting lyophilised peptide powder for laboratory use
Preparing working dilutions from a concentrated stock
Any protocol where a single vial of solvent will be drawn from more than once
It is not the right choice for peptides that are poorly soluble at neutral pH or that degrade there. Those are usually taken into solution with acetic acid water instead.
Handling
Store at controlled room temperature unless the batch documentation says otherwise, and keep the stopper intact and disinfected between withdrawals. The preservative limits growth; it does not compensate for contaminated technique.
Related supplies
Acetic Acid Water for peptides needing an acidic solvent, and Phosphate Buffered Saline where a physiological buffer rather than plain water is required.
Documentation and verification
Certificates of Analysis are published for tested products and batches. A certificate is a batch-specific record: it reports what was measured, by which method, on a stated date, against a batch identifier. It is evidence about the sample analysed at the time of analysis, and it is silent on attributes it does not list and on what has happened to the material since.
The batch number is the field that connects the document to a physical vial. Where the identifier on a vial does not appear on a certificate, the certificate does not describe that vial, however thorough the analysis behind it was. Batch records can be searched directly, and the guides below explain what each field establishes and what it does not.
- Verify a batchSearch a batch number for the certificate records published against it.
- How to read a certificate of analysisWhat each field reports, and the limits of what a certificate can establish.
- Certificate, specification and safety data sheetThree documents that answer three different questions.
- Storage and handlingWhat defined storage conditions mean, and why cold slows degradation.
- Batch numbers and traceabilityHow an identifier ties material to the analysis describing it.
Supplied for laboratory research use only. Not for human or veterinary use.