AB Sciex 4500 Series System User's Manual page 50

Basic Acquisition Methods
Figure 5-1 Ion optics path and parameters (Continued)
Item Parameter
3 CAD Gas
3 CE (Collision
Energy)
3 CES (Collision
Energy Spread)
4500 Series of Instruments
50 of 142
Parameter Use
Type
Source and The CAD parameter controls the
gas pressure of collision gas in the
collision cell during Q3, MS/MS-
type, and LIT scans. For Q3 scans,
the collision gas helps to focus the
ions as they pass through the
collision cell; the preset for the
CAD parameter is in fixed mode.
For MS/MS-type scans, the
collision gas aids in fragmenting
the precursor ions. When the
precursor ions collide with the
collision gas, they can dissociate to
form product ions. For LIT scans,
the collision gas helps to focus and
trap ions in the LIT.
Use the preset value and optimize
for the compound.
Compound The CE parameter controls the
potential difference between Q0
and Q2 (collision cell). It is used
only in MS/MS-type scans. This is
the amount of energy that the
precursor ions receive as they are
accelerated into the collision cell,
where they collide with gas
molecules and fragment.
Use the preset value and optimize
for the compound.
Compound The CES parameter, in conjunction
with the Collision Energy (CE),
determines which three discreet
collision energies are applied to the
precursor mass in an Enhanced
Product Ion (EPI) or MS/MS/MS
(MS3) experiment when CES is
used. By typing a collision energy
spread value, CES is automatically
turned on.
Use the preset value and optimize
for the compound.
Scan Type
Q3 MI, Q3 MS,
MRM, Prec,
NL, EMS, ER,
EPI,
MS/MS/MS,
EMC, and TDF
MRM, MS2,
Prec, NL, and
LIT
EPI and
MS/MS/MS
System User Guide
Document Number: D5030863 A