MassQC Help > Metrics > Dynamic Sampling > MS2 Spectra          
MS2 Spectra

MS2 Spectra is a simple count of the number of MS2 spectra.

A consistent number of MS/MS spectra acquired indicates instrument stability.

The MS2 Spectra metric is the number of MS2 spectra taken during the Retention Spread, the middle elution period during which most peptides elute.

Units:

Count

Optimal:

More MS2 spectra indicate more sampling.

The most reproducible LC-MS performance is when this metric remains in a narrow range over a series of runs. Wide variability in any metric means your process is not reproducible.

What the Metric Detects

The MS2 Spectra metric indicates the effective speed of sampling over the most information-rich section of the chromatogram. If there is insufficient signal to reach the target threshold, or the dynamic exclusions settings are not working as expected, the numbers of MS2 spectra may vary substantially between technical replicates.

Related Metrics:

The MS1 Spectra metric measures the number of MS1 spectra (or number of MS1 scans) over the same Retention Spread time period. The Peptides per Minute metric tells how many peptides were detected in the same time period. The Peaks per Spectrum metric tells how many fragment ions result from the MS2 spectra.

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