ISQ User Guide - Write Frame of Mind

3 Tuning the ISQ
Using ISQ Autotune
• EI Full Tune—This tune is used to completely retune the system. It takes the longest
amount of time to run, but the advantage of using it is that it re-optimizes nearly all the
parameters affecting the signal. This type of tune will perform a mass calibration, tune the
lenses and resolution, and perform a leak check. The detector gain will be calibrated to
generate 300,000 electrons for every ion that strikes the detector. You should run an EI
full tune when the daily tune or the daily tune check is not adequate, when the electron
multiplier is getting old (tuning to high electron multiplier voltages), or the first tune
after you replace the electron multiplier. Unless your SOP requires it, this is not the best
tune to use on a daily basis because of the length of time it takes to run it.
• CI- Tune—This tune is used to analyze samples with negative CI. The standard NCI
tune performs a mass calibration, then tunes the lenses and sets the resolution. This type
of tune assumes you are using methane as the CI reagent gas and tunes the system with a
1.0 mL/min flow. This tune does not set the detector gain.
Note Chemical ionization tunes are very different from the electron ionization tunes. You
should not use a CI tune unless your instrument has a CI ion volume and CI reagent gas
installed.
• CI+ Tune—This tune is used to analyze samples with positive CI. The standard PCI tune
performs a mass calibration, then tunes the lenses and sets the resolution. This type of
tune assumes you are using methane as the CI reagent gas and tunes the system with a
1.5 mL/min flow. This tune does not set the detector gain.
Note To add a tune type to the list, see Modifying an Automatic Tune.
3. Select the Display Report When Complete checkbox so that you can view the tune
report after running the tune.
4. Select the Show Spectra checkbox to show the spectra while the system is tuning.
Thermo Scientific ISQ User Guide 19