MassQC Help > Metrics > MS1 > Ion Inject Time          
MS1 Ion Inject Time

The Ion Inject Time is the time in milliseconds that it takes to fill the ion trap.

Short Ion Inject Times correspond to high signal levels or low threshold settings.

The Ion Inject Time metric is the median time spent collecting ions for precursor spectra.

Units:

Milliseconds (ms)

Optimal:

Lower: Overall lower times may indicate an abundance of ions.

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 Ion Inject Time measures how fast ions are being introduced into the ion trap. The ions are injected until either the trap is full, or until a time threshold is reached. If lots of ions are being injected, then the Ion Inject Time will be short. This may be caused by a high amount of sample injected.

If only a small amount of sample is being injected, then more than half the precursor ions take more than the threshold time to fill the trap and the Ion Inject Time will be pinned at its maximum value.

A gradual drift upward over time in the Ion Inject Time may mean that the ion optics are dirty and thus are hindering the amount of signal reaching the detector. Or it could mean that the ion detectors may need to be examined and recalibrated.

Related Metrics:

The MS1 Ion Inject Time measures the MS1 signal strength. Other measures of the signal strength are the Dynamic Range, the Peak Intensity, and the Total Ion Current.

Related Troubleshooting Topics:
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