An update on my earlier Batch numbers post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.
On the subject in the title: Batch numbers that do not match the vial label — what changed since Working notes rather than a conclusion.
What changes if the standard account of Batch numbers is wrong? I ask because I have been treating it as settled and I noticed this week that I could not say why.
Working through the consequences rather than the evidence, since others here are better placed on the evidence.
Where the same certificate image appears with different lot numbers, that is a documentation finding worth reporting with the images attached.
I would rather be precise about what I do not know than vague about what I do.
Coming back to the opening post, because the follow-up matters more than the original answer.
Keep the two claims separate. "The result on this lot did not match the certificate" is a report that can be checked. "This supplier is dishonest" is an allegation about intent and nothing in a chromatogram supports it.
Filing this under things that are true until someone shows me otherwise.
An update on my earlier Batch numbers post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.
Saving this. It is the version I will quote when the question comes round again.
Post #5 answers the question as asked. The question underneath it is different.
Prices well below the rest of the market are a fact rather than a finding. They are worth noting and they do not establish anything on their own.
I would treat that as a working assumption and revisit it.
Reporting something here requires the batch, the date, the method and the document, which is exactly what makes the reports worth reading two years later.
A supplier changing batch nomenclature is not a warning sign, and it does make historical comparison harder until a mapping exists.
I have deliberately not rounded that, because the rounding is where the argument starts.
Understood. Thank you for being specific about the limits of it.
Picking up post #11: that is the part I would want checked first.
Careful with the language on Batch numbers. "Not detected" and "not present" are different findings and the first is a statement about the method.
Where somebody posts a concern, ask what would resolve it before arguing about it. Half of these threads end with a document nobody had asked for.
I would put this at better than even and not much better.
Patterns that reliably precede a problem: underdosing (less active material than stated, documented by independent testing), mislabelling (wrong compound, wrong strength, or wrong batch on the label), and failure to provide documentation when asked.
Old habit: I write down the expected answer before I calculate it.
Everything in post #15 holds. The case it does not cover is the one I have.
The strongest single signal available cheaply is what happens when you ask a technical question. A quantitative answer inside a working day is difficult to fake at scale.
The short version is the first sentence; the rest is why.
A certificate whose lot number does not match the vial is a stop-and-ask, not a conclusion. Most such things are warehouse paperwork.
Someone will know this better than I do and I hope they say so.
Narrowing post #20, because the general version has more than one answer.
Offering a way to settle Batch numbers rather than another opinion about it. Two measurements, taken the same way, a fortnight apart. If the difference is within the noise, the question was not answerable at this precision.
Everything in post #22 holds. The case it does not cover is the one I have.
The most useful contribution to this subcategory is a resolved case written up with the resolution, because the unresolved ones are all anyone remembers.
Worth checking against a second source before it gets quoted onward.
Evasion when asked: if a supplier does not clarify when asked specifically for method details, counter-ion form, or batch origin, that itself is a red flag worth documenting.
Patterns that reliably precede a problem: underdosing (less active material than stated, documented by independent testing), mislabelling (wrong compound, wrong strength, or wrong batch on the label), and failure to provide documentation when asked.
Post #24 answers the question as asked. The question underneath it is different.
My position on Batch numbers is current rather than settled. I have revised it once already and I expect to again, so treat it accordingly.
Post #27 is the version of this I will quote in future. One addition.
A note on how Batch numbers gets discussed rather than on Batch numbers itself: the confident posts get the replies and the careful ones get ignored, and the careful ones have been right more often.