AssayIndex
Cross-section

L-Carnosine 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 L-Carnosine, with a class minimum gradient of 15 min, the method is a live explanation.

26 recordsmedian 99.58 %spec 99.0 %
LaboratoryReportsGradientMS resolutionMedian purity %Published bias (pp)Bias-adjustedMethod suitability
Janoshik1330minHigh99.46+0.0099.46ADEQUATE
Medutest6 n=625minUnit99.82+0.0899.74ADEQUATE
PeptideMeter5 n=528minHigh99.56-0.0599.61ADEQUATE
VendorInvestigate2 n=232minHigh98.20, 99.30-0.11—ADEQUATE
Nordanalyt035minHigh—+0.02—ADEQUATE
Kestrel015minUnit—+0.24—ADEQUATE
98.198.498.799.199.499.7100.1JanoshikJanoshik: Q1 99.16, median 99.46, Q3 99.72, n=13n=13PeptideMeterPeptideMeter: Q1 99.46, median 99.56, Q3 99.62, n=5outlier 99.18outlier 99.88n=5MedutestMedutest: Q1 99.64, median 99.82, Q3 99.91, n=6outlier 98.95n=6VendorInvestigateVendorInvestigate: Q1 98.47, median 98.75, Q3 99.03, n=2n=2 Purity (% area)
Figure. L-Carnosine 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.