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.

152 recordsmedian 99.38 %spec 98.5 %

Laboratory	Reports	Gradient	MS resolution	Median purity %	Published bias (pp)	Bias-adjusted	Method suitability
Janoshik	68	30min	High	99.43	+0.00	99.43	ADEQUATE
PeptideMeter	30	28min	High	99.43	-0.05	99.48	ADEQUATE
Medutest	19	25min	Unit	99.00	+0.08	98.92	ADEQUATE
Nordanalyt	17	35min	High	99.27	+0.02	99.25	ADEQUATE
VendorInvestigate	11	32min	High	99.16	-0.11	99.27	ADEQUATE
Kestrel	7 n=7	15min	Unit	99.93	+0.24	99.69	BELOW CLASS MINIMUM

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.