MassQC Help > Metrics > Ion Source > Percent +3H          
Percent +3H

Percent +3H is the percentage of all spectra that have a charge of +3.

Higher Percent +3H indicates that the mass spectrometer may favor long peptides.

Percent +3H is calculated by looking at the charge state of all spectra that match to a peptide


Percent (%)



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:

A high Percent +3H means that there are an unusual number of plus 3 ions. This might mean that the electrospray is behaving erratically.

Related Metrics:

Large Percent +3H means that the other charge states don't get as many ions. The metrics Percent +1H and Percent +4H also report the ion's charge state. Any ions that are not charge +1, +3, or +4 are probably charge +2.

If the distribution of charge differs, it may affect the size of the peptides that are detected. Another way to look at this is with the metric Precursor m/z.


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