Accuracy, precision and the tolerance nobody states
Every instrument specification quoted in an advertisement is a best case obtained on a calibration mixture, not on a submitted vial.
Explainers in 2024
Page 5 of 5 of this archive, newest first.
Background rates, and why they matter for attribution
Rapid weight loss by any means raises gallstone risk. Separating that from a direct drug effect requires a comparator, and the trials have one.
The impurity hiding underneath the parent peak
An orthogonal method separates on a different physical principle, so that species co-eluting in the first are likely to resolve in the second. Two runs of the same method at…
Resolving power and mass accuracy are two different specifications
Every instrument specification quoted in an advertisement is a best case obtained on a calibration mixture, not on a submitted vial.
Deamidation, oxidation, and the two shifts worth memorising
What would be needed to catch each of these, and what it would cost.
A percentage is not a specification
Chromatographic purity is cheap, fast and comparable-looking. Those three properties, and not its usefulness, explain why it became the industry’s single figure of merit.
What orthogonal actually means, and what it does not
The most useful single addition to any purity determination is a second separation under a different pH or on a different stationary phase, and the second-most useful is a…
A needle is a single-use instrument
A needle blunts on first use. Reuse is uncomfortable, and it is a documented contributor to lipohypertrophy.
Attribution is the hard part
We give background rates alongside trial rates, because an event occurring during treatment is not thereby caused by it.