The one-quarter rule, and the paper that took it apart
The gap between a defensible recommendation and a confident one is where most of the harm in this subject lives.
Laboratory Notebook in 2024
Page 5 of 5 of this archive, newest first.
What “LC-MS: conforms” tells a reader, which is almost nothing
None of what a checkable identity statement requires is commercially sensitive, and all of it is known to whoever produced the document.
The cold chain in this trade is a gel pack and an optimistic estimate
A gel pack has a finite thermal budget, and once it is spent the payload equilibrates with whatever is outside the box. The only question is how long that takes.
Units, millilitres, milligrams: three scales on one small object
A unit is a volume. A dose is a mass. The bridge between them is concentration, and concentration is a number somebody has to calculate.
Site selection when the tissue has already changed
A rotation scheme that is too complicated will not be followed. We describe the simple ones that are.
Lipohypertrophy, and the absorption it ruins
A rotation scheme that is too complicated will not be followed. We describe the simple ones that are.
What “LC-MS: conforms” tells a reader, which is almost nothing
A short audit procedure, usable by anyone holding a certificate and a calculator.
D-amino acids are invisible to mass spectrometry, and that is the whole problem
Stereochemical inversion changes the molecule, changes its biology, and changes its mass by exactly nothing.
How to read the silence on a certificate you already hold
Our position is about documentation practice. It is not an allegation about anybody’s honesty, and we are explicit about the difference.
Why a 0.036-dalton difference is the hardest number in peptide identity
Parts per million sound impressive until they are converted into daltons at the molecular weight of the thing being measured.