Unable to use MQL to target z=6 (or higher) precursors

[Ivo Hendriks]

Hi all,

This is actually a bug (or missing feature) I ran into quite a few months ago, and just remembered to report. I also expect you might be aware of this since the default maximum charge state in MQL is z=5.

When increasing the maximum charge state higher than 5 (for large LysC-digested peptides), any scans that are targeted at z=6 or higher are rejected by the MS (Q-Exactive HF-X) and interrupt MQL for 5-10 seconds. It does resume afterwards, but causes a lot of 'gaps' in the RAW file because it temporarily reverts to Xcalibur control meaning it just makes idle 'magic scans'. This is while using the TopN app.

Best regards,

Ivo Hendriks