Sterile Water is preservative-free water for laboratory dilution: no bacteriostat, no buffer and no tonicity agent, supplied in small single-entry volumes. It is the diluent to use when anything added to the water would confound the measurement.
About Sterile Water
The specification is defined by what is absent. There is no benzyl alcohol, so nothing absorbs in the ultraviolet range that would distort a spectrophotometric concentration reading, and nothing in the vial is cytotoxic to cultured cells. There is no buffer, so the pH of the final solution is set entirely by the compound being dissolved and by anything else deliberately added. There are no salts, so the solution is hypotonic unless tonicity is supplied separately.
The trade-off is protection. Without a bacteriostat the water offers no resistance to microbial growth once the closure has been entered, so a vial is treated as single-entry and the remainder discarded rather than kept. Where a stock solution needs to survive repeated sampling over days, bacteriostatic water is the better-matched diluent.
What the research covers
Preservative-free water is the default diluent for work where the solvent must contribute nothing: cell-based assays, UV and HPLC quantification of a reconstituted peptide, mass-spectrometry sample preparation, and any experiment in which a preservative would appear as a peak, a cytotoxic effect or an unexplained absorbance. It is also the correct starting point when a buffer or saline is being made up to a defined composition, since the water itself adds no ions.
Further reading in the Amino Club library: peptide reconstitution supplies sets out the choice between preservative-free and bacteriostatic diluents and the handling that follows from it.
Sterile Water specification
- Strengths available: 3ml, 10ml
- Presentation: supply
- Purity: ≥99% by HPLC, identity confirmed by mass spectrometry
- Released against: the Certificate of Analysis for its own batch
Handling Sterile Water
Store the sealed vial at room temperature, out of direct sunlight, and do not freeze. Inspect before use and discard any vial that is not clear and colourless or whose seal is compromised. Because there is no bacteriostat, laboratories draw once and discard the remainder rather than returning a part-used vial to storage; stocks made up in preservative-free water are themselves kept cold and treated as short-lived.
Certificates, delivery and terms
This batch ships with the Certificate of Analysis carrying the batch number printed on its label; how that is tested and released is set out on the lab testing page. Delivery, customs and returns are covered on the shipping page, common questions on the FAQ, and quantity pricing through bulk and wholesale. Supplied for in-vitro laboratory research only: not a medicine, not a supplement, not for human or veterinary use, and no dosing or administration guidance is provided — see the research use policy.
