Worth separating two things that post #4 runs together.
Specificity: the method can distinguish the intended compound from related impurities and degradation products. Tested by comparing results on pure compounds, mixtures of compounds, and degraded samples.
I read post #15 twice before replying, because I had assumed the opposite.
Specificity: the method can distinguish the intended compound from related impurities and degradation products. Tested by comparing results on pure compounds, mixtures of compounds, and degraded samples.
Stability-indicating method: one that can separate a compound from its degradation products. Critical for assay methods that claim to measure actual degradation (as opposed to purity, which is orthogonal).
I read post #22 twice before replying, because I had assumed the opposite.
Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own records is not any individual result; it is that they are dated and consecutive.
post #37 is right about the mechanism and I think understates the practical bit.
Linearity: the detector response is proportional to compound concentration across the working range. Demonstrated by running standards at multiple concentrations and showing R-squared values typically ≥0.99.
Specificity: the method can distinguish the intended compound from related impurities and degradation products. Tested by comparing results on pure compounds, mixtures of compounds, and degraded samples.
Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.
The correction was fair and I had been repeating something I had not checked carefully enough.
Specificity: the method can distinguish the intended compound from related impurities and degradation products. Tested by comparing results on pure compounds, mixtures of compounds, and degraded samples.
Read the full topic (59 posts)
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An inter-laboratory comparison on one lot, tabulated
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About the Method validation category
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+1 | 5 | 468 | 5mo |
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+47 | 51 | 40k | 10mo |
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When to suspect the method rather than the sample
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+109 | 115 | 63k | 15mo |
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When to suspect the method rather than the sample
When to suspect the method rather than the sample — that is the question, and I have not found it answered plainly anywhere I have looked. Posting the method first, because I know what the first three replies…
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+109 | 115 | 63k | 15mo |
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Reflectance and photometric devices: precision in practice
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2 | 2.2k | 10mo | |
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About the Method validation category
Specificity, linearity, precision, accuracy, robustness, system suitability, and why two labs disagree. This post is a community wiki: any member at trust level 3 or above can edit it, and every edit is…
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+1 | 5 | 468 | 5mo |
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+4 | 8 | 25k | 22mo |