Cross-section

Semax 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 Semax, with a class minimum gradient of 15 min, the method is a live explanation.

216 recordsmedian 99.46 %spec 98.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	99	30min	High	99.51	+0.00	99.51	ADEQUATE
PeptideMeter	39	28min	High	99.27	-0.05	99.32	ADEQUATE
Medutest	31	25min	Unit	99.66	+0.08	99.58	ADEQUATE
VendorInvestigate	21	32min	High	99.09	-0.11	99.20	ADEQUATE
Nordanalyt	16	35min	High	99.59	+0.02	99.57	ADEQUATE
Kestrel	10	15min	Unit	99.46	+0.24	99.22	ADEQUATE

Figure. Semax 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.