224
7 Analyzer
Mass filter
AMU offset
AMU offset (AmuOffs) also affects the ratio of dc voltage to RF frequency on the
mass filter.
• Higher offset yields narrower peaks.
• AMU offset generally affects peak widths equally at all masses.
219 width
m/z 219 is a prominent ion near the middle of the mass range of PFTBA. The
width parameter (
Wid219) makes small corrections to the m/z 219 peak width.
Amu gain and amu offset must be readjusted after the 219 width is changed. If you
are tuning with a compound other than PFTBA, there may not be an ion at m/z
219. In that case, set the 219 width to the last value found for it by Autotune or set
it to 0.
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