AB Sciex QTRAP 4500 LC/MS/MS system, System User'S Manual, Page: 61 / 138

Operating Instructions — Acquisition Methods
System User Guide 4500 Series of Instruments
RUO-IDV-05-0264-A 61 of 138
6 MCS (Multi-
Charge
Separation)
Barrier
Compound The MCS Barrier parameter controls
the voltage used to eliminate the
singly-charged ions from the LIT.
Use the preset value.
EMC
6 Q3 Cool Time Compound The Q3 Cool Time parameter
controls the amount of time that the
precursor ions are allowed to cool
prior to collection of their product
ions.
Use the preset value.
TDF
7 MS/MS/MS
Fragmentation
Time
Compound The MS/MS/MS Fragmentation Time
parameter controls the amount of
time that the excitation energy is
applied. It is used in combination with
the excitation energy to fragment the
isolated second precursor ion.
Use the preset value.
MS/MS/MS
7 Fixed LIT Fill
Time
Compound The Fixed LIT Fill Time parameter
controls the amount of time that the
LIT fills with ions.
Use the preset value.
EMS, EPI,
MRM, and
MS/MS/MS
7 DFT (Dynamic
Fill Time)
Compound DFT dynamically calculates the
length of time that ions are collected
in the LIT based on the incoming ion
signal. When DFT is turned on the
signal is optimized to either increase
sensitivity or minimize space-
charging.
Either select or clear the feature
based on the experiment.
In the
Tools > Settings > Method
Options dialog, the Dynamic Fill
Time settings are optimized for the
10 000 Da/s scan speed. These
settings are also suitable for other
LIT scan speeds.
EMS, EPI,
ER, and
MS/MS/MS
8 CEM (CEM) Detector The CEM parameter controls the
voltage applied to the detector. The
voltage controls the detector
response.
All
Item
Parameter Parameter
Type
Use Scan Type