AssayIndex
Mass spectrometry

Mass accuracy

Difference between measured and theoretical mass, in ppm of the theoretical value. A relative measure — the same ppm is a different absolute error at different masses.

Related terms

ppm
Parts per million. Used for mass accuracy: ppm = (observed − theoretical)/theoretical × 10⁶.
see also Mass accuracy
Rule AX-R01
Mass accuracy outside the class limit. Records identity as not established rather than failed, because most instances are calibration problems.
see also Mass accuracy

Where this term appears

The glossary exists to make record pages readable without a chemistry degree. Every technical term on a report resolves here.