"Greater than or equal to 99%" as a specification rather than a result posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.
A document that puts the specification in the result column has told you the release criterion rather than the measurement. Those are different claims and the difference is the whole point of reading the document.
One of those cases where knowing the mechanism does not help the decision.
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Picking up post #61: that is the part I would want checked first.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
Not a conclusion. A place to stand while looking for one.
This follows post #65 rather than contradicting it.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
Someone should write this up properly, and it should probably not be me.
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Where I part company with post #65, and it is a narrow parting.
A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.
Post #68 is the version of this I will quote in future. One addition.
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
Asking for the batch record rather than the certificate is a reasonable request and the response to it is informative whichever way it goes.
If this contradicts something upthread, the upthread version may well be the better one.
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
The literature is thinner on this than the confidence in the thread implies.
That is a cleaner way of putting what I was circling around.
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A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.
It took me longer than it should have to see that.
The fields that make one usable: lot identifier matching the container, test date, method identification specific enough to reproduce, the result as a number, and the acceptance criterion stated separately from the result.
On balance I think that is right, and I would not bet much on it.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
I would treat that as a working assumption and revisit it.
On post #74 — agreed on the reasoning, with one qualification.
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
I have separated what I observed from what I concluded, which does not always happen.
Taking post #76 at face value and following it one step further.
A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.
Post #78 and I disagree about the size of the effect, not about the direction.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
I read post #79 twice before replying, because I had assumed the opposite.
When a document puts the specification in the result column, it has told you the release criterion, not the measurement. Those are different claims and the second is weaker.
That holds under the stated conditions and I have stated them.
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
Reading it back, the second half matters more than the first.
Taking post #83 at face value and following it one step further.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
This is the sort of thing the wiki should carry and currently does not.
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A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.
Worth separating two things that post #83 runs together.
A document that puts the specification in the result column has told you the release criterion rather than the measurement. Those are different claims and the difference is the whole point of reading the document.
The short version is the first sentence; the rest is why.
This follows post #87 rather than contradicting it.
A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.
That is all the detail I have. Someone else will have more.
The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".
The arithmetic in post #87 is right; the assumption feeding it is the part to check.
An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.
The uncertainty is in the assumption, not in the calculation.