Use the chromatographic peak Apex Detection filter to trigger data-dependent scans. You obtain the highest quality data in the shortest period of time by deferring data acquisition until near the apex of a chromatographic peak.
The use of apex detection provides numerous benefits for data-dependent LC/MS/MS, including the following:
- Improved MS/MS quality and signal levels
- Shorter ion injection times
- Reduced MS/MS acquisition of chemical background
- Less dependence on static or dynamic exclusion lists
- Reduced re-triggering of scans on tailing chromatographic peaks
The following table describes the parameters in the Apex Detection Properties pane.
Parameter | Description |
|---|---|
Expected peak width (FWHM, s) | The expected peak width (in seconds, full-width half-maximum [FWHM]) of the expected chromatogram peak. Range: 1–60; default: 30 |
Desired Apex Window (%) | The desired apex triggering window (as a percentage of the peak width). The MS fits Gaussian functions to the extracted ion chromatograms and from them and the expected peak width, determines whether the chromatogram is within the triggering window. If it is and the signal is above the threshold, the MS performs a data-dependent scan on that ion. Range: 0–100; default: 30 |