Specification in the result column: why that is a meaningful error posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
I read post #60 twice before replying, because I had assumed the opposite.
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 want a second opinion before relying on that.
Taking post #62 at face value and following it one step further.
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.
I am describing what is, rather than arguing for what should be.
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.
That is all the detail I have. Someone else will have more.
Grateful for the specificity. Vague answers to this question are what sent me looking.
Building on post #66 rather than restating it.
A certificate of analysis is a statement by its issuer that a defined test was performed on a defined lot and produced a defined result. That is all it is, and it is not nothing. What makes it usable: lot identifier matching the container, test date, method identification specific enough to reproduce, the actual result as a number, and the acceptance criterion stated separately from the result.
Post #64 put the caveat in the right place and I want to underline it.
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 seen it go both ways, which is why I hedge.
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".
Stating my assumptions rather than smuggling them in.
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.
The right answer here may simply be that it has not been measured.
Answering the question post #67 raises rather than the one it answers.
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.
A test date preceding a manufacturing date is a clerical error until somebody explains otherwise, and asking is cheap. Most such things are transcription.
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".
Marking that as an opinion rather than a finding.
A certificate is a statement by its issuer that a defined test was performed on a defined lot and produced a defined result. That is all it is, and it is not nothing.
The reasoning is more useful than the number, which is why I have shown it.
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.
Someone will know this better than I do and I hope they say so.
Post #75 is the version of this I will quote in future. One addition.
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.
I checked the source rather than the summary, and they differ.
Method identification means enough to reproduce: column chemistry, dimensions, gradient, flow, wavelength. A method name alone identifies a family of methods.
Where I would look next, rather than where I would stop.
This is the answer, and the reason it is the answer is the more useful part.
Answering the question post #78 raises rather than the one it answers.
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.
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 checking against a second source before it gets quoted onward.
"Not less than 98 per cent" is a specification. "98.3 per cent" is a result. A certificate carrying only the first has not told you what was measured.
Happy to expand any of that if it is the useful part.
Adding the measurement that post #84 says would settle it.
What fields matter on a certificate: lot number matching the vial, test date, the analytical method stated specifically, the measured result as a number, and the acceptance limit stated separately. A certificate missing any of these is weaker.
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".
Second-hand, so weight it accordingly.
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.
Posting it because the silence on this was starting to look like agreement.
Where I part company with post #86, and it is a narrow parting.
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.
A test date preceding a manufacturing date is a clerical error until somebody explains otherwise, and asking is cheap. Most such things are transcription.
I have left out the parts I could not verify.
"Not less than 98 per cent" is a specification. "98.3 per cent" is a result. A certificate carrying only the first has not told you what was measured.
Reading it again, the caveat matters more than the finding.