Cross-section

PT-141 (Bremelanotide) 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 PT-141 (Bremelanotide), with a class minimum gradient of 22 min, the method is a live explanation.

200 recordsmedian 99.31 %spec 98.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	94	30min	High	99.22	+0.00	99.22	ADEQUATE
Medutest	33	25min	Unit	99.58	+0.08	99.50	ADEQUATE
PeptideMeter	31	28min	High	99.24	-0.05	99.29	ADEQUATE
Nordanalyt	18	35min	High	99.31	+0.02	99.29	ADEQUATE
Kestrel	14	15min	Unit	99.93	+0.24	99.69	BELOW CLASS MINIMUM
VendorInvestigate	10	32min	High	99.03	-0.11	99.14	ADEQUATE

Figure. PT-141 (Bremelanotide) 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.