Dwell Time effect on Sensitivity

[John Thaden, Ph.D.]

Hi all, a theory question:

If I double the dwell time for a particular ion, does theory predict
that my signal-to-noise will increase by 1.414 (square root of 2)? I
need to know this to make rational allocations of my scan cycle to
different ions of interest.

Background:

- I'm doing LC-MS with a transmission quadrupole mass spec.

- The change in dwell causes no change in scan cycle time, overall
(some other ion is scanned less long).

- There are 20 scans across a well shaped chromatographic peak.

- The MS mode Q1 scan mode.

- A 'micro-scan' occurs for each ion of interest, +/- 0.35 amu around
its monomolecular mass.

Thank you,
-John