A laboratory-water certificate needs its formulation, chemical measurements and microbiological tests read separately. The supplied example below includes two unresolved questions: the TOC sample basis and the sterility-test dates.
Identify the formulation and sample stage
The supplied 3 mL report is MA-WFI-0047, revision 01, lot WFI-47-ADP. It describes bacteriostatic water containing 0.9% benzyl alcohol. Keep the stated formulation separate from unspecified water, and establish whether each result concerns starting water or the finished formulation.Water report (PDF) (opens in a new tab)
Keep every result and unit separate
| Attribute | Result | Stated requirement |
|---|---|---|
| Benzyl alcohol | 0.90% | 0.85–0.95% |
| pH | 5.6 | 4.5–7.0 |
| Conductivity at 25 °C | 0.82 µS/cm | ≤1.3 µS/cm |
| Total organic carbon | 0.18 mg/L | ≤0.50 mg/L |
| Bacterial endotoxins | <0.25 EU/mL | ≤0.25 EU/mL |
| Sterility | No growth | No growth |
| Fill volume | 3.04 mL | ≥3.00 mL |
This transcription does not confirm the validity of the results. The less-than endotoxin entry is a bound, not an exact zero. Keep the original concentration notation for benzyl alcohol; if its percentage basis is needed, obtain that definition rather than silently converting between mass-per-volume and volume-per-volume.Water report (PDF) (opens in a new tab)
Conductivity responds to ionic contributions and depends on temperature. Preserve the report’s 25 °C condition and ask which sample stage was measured. Conductivity is not a count of every dissolved constituent.USGS — Conductivity and water (opens in a new tab)
Leave the TOC basis unresolved
USP’s public introduction describes total organic carbon as an indirect measure of organic material expressed as carbon. TOC is a separate analytical question from endotoxin and microbial tests.USP TOC introduction (opens in a new tab)
The supplied report places 0.90% benzyl alcohol beside 0.18 mg/L TOC. Benzyl alcohol is an organic compound, so this raises a sample-basis question: does TOC describe starting water, the finished formulation or a specifically processed or corrected sample? The report does not explain the relationship.Water report (PDF) (opens in a new tab)USP TOC introduction (opens in a new tab)
Clarify the test timeline
The report records receipt on 4 September, analysis on 5–6 September and approval on 7 September 2026, alongside a USP <71> “No growth” result. USP’s public <1071> introduction describes at least 14 days of incubation for conventional growth-based <71> tests. The apparent interval therefore needs clarification.Water report (PDF) (opens in a new tab)USP sterility-test context (opens in a new tab)
Ask for the complete test start and finish dates and the actual method. The listed dates might be incomplete, or other records might apply; the PDF alone does not answer this. Do not describe it as independently verified evidence of a completed conventional <71> test or substitute a guessed date.Water report (PDF) (opens in a new tab)USP sterility-test context (opens in a new tab)
Request a linked clarification
A useful response identifies the sample stage for each chemical result, the full sterility-test timeline and any corrected report version. Preserve both the original document and the issuer’s explanation so the unresolved points remain traceable.Water report (PDF) (opens in a new tab)
Sources and further detail
- Supplied bacteriostatic water 3 mL certificate (opens in a new tab)
MA-WFI-0047, revision 01; task TJK2ADP; lot WFI-47-ADP. TOC sample basis and sterility-test timing remain unresolved; see the article. The cited PDF was re-read on 3 October 2026 to check this transcription; its issuer and findings were not independently authenticated.
- USP — General chapter <643>, public introduction (opens in a new tab)
Public 2021 chapter preview, not the full current subscribed standard. Supports the definition of TOC and its separation from microbiological control.
- USP — General chapter <1071>, public introduction (opens in a new tab)
Public 2025 chapter preview. Its introduction identifies the minimum 14-day incubation of the conventional growth-based <71> tests; the full current subscribed standard was not accessed.
- USGS — Conductivity and water (opens in a new tab)
Official explanation of ionic contributions and temperature dependence.
Revised from the existing source dossier on 3 October 2026. Supplied-report values are document transcriptions, not independent authentication or new measurements. Source notes identify the scope of each reference; this article has not undergone independent scientific peer review.