Cross-section

MGF by laboratory

The same compound measured by different laboratories on different gradients. Where the medians differ, the question is whether the material differed or the method did — and for MGF, with a class minimum gradient of 15 min, the method is a live explanation.

32 recordsmedian 98.73 %spec 97.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	20	30min	High	98.73	+0.00	98.73	ADEQUATE
PeptideMeter	4 n=4	28min	High	98.84	-0.05	98.89	ADEQUATE
Medutest	3 n=3	25min	Unit	98.30	+0.08	98.22	ADEQUATE
Nordanalyt	2 n=2	35min	High	99.17, 99.04	+0.02	—	ADEQUATE
Kestrel	2 n=2	15min	Unit	99.04, 98.48	+0.24	—	ADEQUATE
VendorInvestigate	1 n=1	32min	High	97.64	-0.11	—	ADEQUATE

Figure. MGF purity by contributing laboratory. Any offset between rows has two possible sources — a real difference in the material each laboratory happened to receive, and the laboratory's own bias — and this figure cannot separate them. The paired analysis that can is on inter-lab agreement.