Analytics · Mass spectrometry · continued

What a 2 ppm match establishes, and what it does not posts 61–61

Analytics › Mass spectrometry high-resolution MS charge states LC-MS MALDI-TOF

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

FairweatherTL2Member19 Oct 2025 · edited#61

Mass accuracy is expressed in parts per million. It is the difference between observed and theoretical mass divided by theoretical mass, multiplied by a million. A high-resolution instrument in good calibration achieves low single-digit ppm on a peptide of this size.

Written from notes rather than memory, which is why the numbers are specific.

19 likes 9mo

This topic was referenced in

Mass error in ppm: the arithmetic and the caveatAnalytics › Mass spectrometry · 125 replies
Mass error in ppm: the arithmetic and the caveat — a second datasetAnalytics › Mass spectrometry · 24 replies

Moved from HPLC & UHPLC by hana.sato. Category placement is not obvious from outside and getting it wrong is expected. This topic will get better answers here. The move is recorded in the public log citing R7.

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