Bacteriostatic Water Lot Number: What It Means for Your Research
A bacteriostatic water lot number pins a 10 mL vial to a single production batch of 0.9 % benzyl alcohol in Type I borosilicate glass. The code lives on the label, the QR tag, and the Certificate of Analysis (CoA) that ships with each lot. Scan the QR and the lot-specific CoA appears instantly, showing USP <71> sterility results, USP <85> endotoxin limits, and an HPLC-UV benzyl alcohol assay. For a catalog of 10 mL vials, visit BAC Water Depot's 10 mL vial catalog.
What a Lot Number Does and Does Not Tell You
A lot number is a batch identifier, not a code to decode. Vendors use their own schemes, and the digits do not reliably reveal a production date or line. What the lot number reliably does is connect the vial in your hand to one Certificate of Analysis: the sterility, endotoxin, microbial and benzyl alcohol results that were measured on that batch. Upon receipt, the lab tech should match the vial’s lot number with the packing list and the CoA stored in the lab’s records.
A QR code sits on the vial’s back label. Scanning it with a smartphone or a lab-grade scanner opens a secure URL hosted by BAC Water Depot, where the per-lot CoA is offered as a PDF. The CoA lists:
- Sterility test – USP <71> membrane filtration, 14-day incubation, no growth.
- Bacterial endotoxin – USP <85> LAL assay, ≤ 0.25 EU/mL.
- Microbial analysis – validated PCR assay, no detectable microbial DNA.
- Benzyl alcohol content and identity – HPLC-UV, 0.90 % ± 5 %.
- Container closure integrity – USP <1207>.
Because the QR resolves to that lot’s CoA page, a later deviation review or reproducibility audit can retrieve the same analytical data the lab saw on the day the vial was received.
For deeper insight into lot-level documentation, see our buying guide and the knowledge base.
Step-by-Step Workflow for Recording Lot Numbers in the Lab Notebook
Accurate lot-number logging underpins reproducibility. Follow this numbered workflow, which folds the QR-code CoA into routine notebook entries:
- Receive and inspect the shipment. Verify an intact QR code and a legible lot number on each vial.
- Scan the QR code with a phone or lab scanner; save the CoA to the shared drive under Bacteriostatic Water – CoA.
- Record the lot number in the notebook exactly as printed on the label.
- Note the expiration date and storage conditions (15–30 °C unopened, 2–8 °C after puncture, discard after 28 days).
- Link the CoA: write the file path or attach a printed copy beside the experimental details.
- Cross-reference the water lot with any reagents that will be reconstituted (peptides, lyophilized antibodies).
- Sign and date the entry, confirming the correct lot was used.
| Step | Action | Documentation |
|---|---|---|
| 1 | Visual inspection | Packing list, vial label |
| 2 | QR-code scan | CoA saved to the lab’s records |
| 3 | Notebook entry | Lot number as printed on the label |
| 4 | Storage note | 15–30 °C unopened |
| 5 | CoA attachment | File path or printout |
| 6 | Reagent linkage | Cross-referenced with peptide batch |
| 7 | Sign-off | Investigator initials & date |
Log the entry at the bench, not at the end of the day: lot numbers copied from memory are the most common traceability error we hear about.
Why QR-Code Access to the Certificate of Analysis Helps
The QR tag on each vial opens the lot-specific CoA at bacwaterdepot.com/coa/<lot-number>. In practice that removes several friction points:
- Rapid verification – a technician reads the lot’s results in seconds instead of searching for a paper insert.
- No detached paperwork – the CoA stays reachable from the vial itself, even after the shipping box is gone.
- Audit readiness – an auditor can scan the vial on the spot and see the data for that batch.
- Consistency – everyone in the lab reads the same document for the same lot.
Every lot is tested by an independent third-party laboratory, and the results published on that lot’s CoA cover USP <71> sterility, USP <85> bacterial endotoxin, microbial analysis by PCR, benzyl alcohol content and identity by HPLC-UV, pH, subvisible particulates and container closure integrity.
Which BAC Water Depot SKU fits this use case? Scenario A – Small-scale peptide reconstitution (≤10 vials): 10-pack $74.99 · $7.49/vial Scenario B – Medium-scale cell-culture work (10-25 vials): 25-pack $174.99 · $6.99/vial Scenario C – High-throughput screening labs (≥50 vials): Bulk program /bulk from $6.49/vial
Citing the Lot Number in Methods and Records
When publishing, disclose every reagent’s lot number in the Materials and Methods section. For bacteriostatic water, the recommended citation reads:
“Bacteriostatic water (0.9 % w/v benzyl alcohol, Type I borosilicate glass, 10 mL) was obtained from BAC Water Depot (lot number as printed on the vial; CoA available via QR code).”
Naming the exact water lot in the methods section lets any later variability be attributed correctly, especially when the study reconstitutes lyophilized peptides or proteins with it.
Central inventory systems can store the lot number alongside SKU and expiration date. Linking the inventory entry to the QR-code URL creates a “digital twin” of the vial, enabling automated alerts when a lot nears its discard window (28 days after puncture) or expiration date.
Common Mistakes to Avoid
- Assuming lot numbers are interchangeable between manufacturers; each vendor uses its own schema.
- Ignoring the QR code and relying solely on printed CoA, which may detach from the vial.
- Recording only the expiration date without the lot number, breaking traceability.
- Keeping a punctured vial past 28 days, or leaving it at room temperature instead of 2–8 °C.
- Failing to cross-reference the water lot with peptide or antibody batch numbers, obscuring sources of experimental variance.
People Also Ask
What does a bacteriostatic water lot number indicate? It identifies the production batch and links the vial to that batch’s Certificate of Analysis, including the USP <71> sterility and USP <85> endotoxin results.
How can I access the Certificate of Analysis for a specific lot? Scan the QR code printed on the vial; it opens the per-lot CoA page showing the sterility, endotoxin, microbial and benzyl alcohol results for that batch.
Is the lot number the same as the product number? No. A lot number identifies one production batch; a catalog or product number identifies the product itself and stays the same from batch to batch.
Why is it important to log the lot number in my lab notebook? Logging ties experimental results to the exact vial batch used, so a result can be checked against that batch’s Certificate of Analysis later.
Can I reuse a bacteriostatic water vial after 28 days? No. Once punctured, the vial should be refrigerated at 2–8 °C and discarded after 28 days.
Does BAC Water Depot test each lot for endotoxin? Yes. Every lot undergoes USP <85> LAL testing, with results documented in the QR-code linked CoA.
About BAC Water Depot: Research-grade bacteriostatic water for qualified research institutions and laboratory buyers. ISO 9001:2015 registered US facility, verified by an independent testing laboratory, per-lot Certificate of Analysis. Same-day US shipping before 2 pm CT. Browse the catalog → · For research and laboratory use only — not for human or veterinary use.
Last reviewed: 2026-10-06