What should FIA peaks look like and how can the peak shape be improved?

What should FIA peaks look like and how can the peak shape be improved?

  1. The best peak shapes are obtained by avoiding unnecessary dead volumes (caused by valves or connection parts) and connecting the injector directly to the mass spectrometer. For this, red PEEK tubing is recommended.
  2. The FIA peaks must be located approximately in the middle of the data acquisition window, rather earlier than later. It is important that the peaks are not cut off or running out of the window.
  3. The peaks must not show “satellite” or large shoulder peaks.
  4. The peaks must have a defined beginning and ending without interruptions. They must not show huge valleys in between or be too jagged (stable spray).
  5. Jagged peaks are typically caused by an instable electrospray. In that case, rinse at high flow rate using different solvents or replace the ESI electrode.
  6. Huge and broad valleys can be caused by ion suppression. In that case, dilute the samples further.
  7. Refer to the user manual for more information and SST criteria.

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