Research supplies & diluents
Sterile Laboratory Water
Sterile water is water that has been sterilised and contains no preservative, no buffer and no tonicity agent. The absence of a preservative is the defining property: it keeps the diluent analytically and biologically neutral, and it means a vial is conventionally treated as single-use once entered. VaultLabs supplies it in 3 ml and 10 ml vials as a laboratory reagent for in vitro reconstitution work.
Research use only. For in vitro research use only. Not for human or animal consumption. Not for human consumption, medical use, or personal application.
Reviewed by VaultLabs Research Editorial Desk · Last updated 2026-09-13
Key facts
- Sterile water contains nothing but water — no benzyl alcohol, no buffer, no tonicity agent.
- Because nothing suppresses growth after the closure is pierced, an opened vial is conventionally treated as single-use.
- It is the usual choice for cell-based work and for analytical methods where a preservative peak or UV absorbance would confound the measurement.
- It is not "purer" than bacteriostatic water; the two differ in preservative content, not in water quality.
- Reconstitution arithmetic is identical whichever diluent is used — a 10 mg vial taken to 2 ml is 5 mg/ml.
- Material type
- Unpreserved aqueous diluent
- CAS number
- Not applicable — supplied as a sterile aqueous diluent
- Water component
- Water, CAS 7732-18-5 (H₂O, 18.02 g/mol)
- Preservative
- None
- Appearance
- Clear, colourless aqueous solution in a sealed vial
- Catalog presentations
- 3 ml and 10 ml vials
- Storage
- 15–25 °C sealed, protected from contamination
- Supply status
- Research use only — not for human or animal use
What sterile water is
Sterile water is exactly what the name says: water that has been sterilised, with nothing added. No preservative, no buffer, no salt. In a reconstitution workflow that neutrality is the whole point — whatever ends up in the analysis came from the peptide and the method, not from the diluent.
It has no CAS number as a supplied article because it is water in a container; the substance itself is water, CAS 7732-18-5. There is no second component to declare, which is why a sterile water certificate is shorter than a bacteriostatic water certificate.
As with the preserved material, the compendial pharmaceutical article of a similar name is a licensed drug product with its own regulatory status. VaultLabs supplies research-grade sterile laboratory water as a reagent, and does not supply that drug product.
When to choose it over bacteriostatic water
The trade-off runs one way. Sterile water gives you a clean background and costs you multi-draw shelf life; bacteriostatic water gives you multi-draw shelf life and costs you a clean background.
Pick sterile water when the SOP mandates single-use preparation, when the work is cell-based (benzyl alcohol is documented as cytotoxic to cultured cells above low concentrations), or when an analytical method would register the preservative — a preservative peak in a reversed-phase chromatogram or added UV absorbance is a real artefact, not a theoretical one.
Pick preserved water when the same preparation vial will be entered several times over days and nothing in the method cares about benzyl alcohol. A side-by-side breakdown is on BAC water vs sterile water.
Volume, documentation and lot control
Because the material is conventionally single-use once entered, vial size should track how much a single preparation consumes rather than how much a week consumes. A laboratory that routinely uses under 2 ml per preparation wastes less with the 3 ml vial; one preparing larger volumes in a single session may still prefer 10 ml.
Record the diluent lot next to the peptide lot. Where a certificate has been published for a VaultLabs lot, check the number against batch verification or find it through COA search before the vial is opened. How to read a peptide COA explains the fields, and the COA receiving checklist is the bench-side version.
Concentration arithmetic does not change with the diluent. The peptide reconstitution calculator converts vial strength and water volume into concentration per unit volume; reconstitution basics covers the underlying method.
Handling and storage
Sealed vials sit at 15–25 °C, protected from light and contamination. Refrigeration is unnecessary for the unopened material. UAE ambient storage rooms can drift above the labelled range in summer, which is worth measuring rather than assuming — see the research peptide storage guide.
After first entry there is no preservative doing anything, so residual volume should be handled per your SOP; most quality systems will treat the vial as spent. Do not use a vial that arrived with a compromised seal or visible particulate.
VaultLabs sterile water is supplied for in vitro laboratory research only — not for human or animal use. Catalogue SKUs are grouped at sterile water.
Research interest areas
Single-use reconstitution
Short-duration analytical prep
Diluent qualification
Storage information
15–25 °C (room temperature, sealed)
Keep sealed vials at labelled room-temperature storage. Once opened, treat unused volume per your SOP — this is typically a single-use material.
Stability notes
Opened-vial hold time is defined by the receiving laboratory’s SOP. Do not use a vial that arrived with a compromised seal.
Selected literature
Named papers behind the statements on this page. Each entry resolves on PubMed and through its DOI, so you can read the source rather than take our summary of it. Inclusion describes the research record and is not a claim about this material’s suitability for any use.
Role of benzyl alcohol in the unfolding and aggregation of interferon α-2a
Bis RL, et al. · Journal of Pharmaceutical Sciences · 2015
Evidence that the preservative in bacteriostatic water can act on protein conformation, supporting the unpreserved-diluent choice.
Mechanisms underlying benzyl alcohol cytotoxicity (triamcinolone acetonide preservative) in human retinal pigment epithelial cells
Chang YS, et al. · Investigative Ophthalmology & Visual Science · 2011
In vitro cytotoxicity of benzyl alcohol in cultured human cells, the standard reason cell-based protocols specify preservative-free water.
Databases and verification
Registry and database entries for independent identity checks. These are standing searches rather than fixed records, so they stay current as new work is indexed.
- Water — CAS Registry record (7732-18-5) — CAS Common Chemistry
- Water compound record — PubChem
- Benzyl alcohol preservative effects on protein formulations — PubMed
FAQ
As a neutral diluent for reconstituting lyophilised research material, where the absence of a preservative keeps the analysis free of a component the diluent introduced. It carries no active substance of its own.
Neither is better; they solve different problems. Sterile water gives an analytically clean background but no multi-draw shelf life once entered. Bacteriostatic water gives multi-draw shelf life but introduces benzyl alcohol, which absorbs in the UV and is cytotoxic to cultured cells above low concentrations.
Nothing in the vial suppresses growth after the closure is pierced, so most quality systems treat it as single-use. Hold time, if any, is defined by the receiving laboratory's SOP rather than by a VaultLabs specification.
Because benzyl alcohol, the preservative in bacteriostatic water, is documented in the in vitro literature as cytotoxic to cultured human cells above low concentrations. Removing it removes a variable the experiment did not intend to introduce.
It can, depending on the molecule. Published formulation work reports benzyl alcohol promoting unfolding and aggregation of specific recombinant proteins in reconstituted lyophilised preparations. Those findings are protein-specific rather than universal, but they are why methods sensitive to aggregation state generally specify unpreserved water.
No. It is a research-use laboratory diluent supplied for in vitro work only. VaultLabs does not supply materials for human or animal consumption or administration.