SCIEX X500 QTOF System User's Manual page 95

Table 6-9 MS Method Parameters (continued)
Parameter Definition
ITC Ion Transmission coefficient (ITC) parameter
attenuates the ion beam to avoid saturation and
to prevent premature wear to the MCP plates. In
TOFMS mode, the ion attenuation is adjusted
dynamically by the software and a corresponding
correction factor applied to the data output. In MS/
MS, there is usually no beam attenuation so the
calculation is not necessary.
Precursor ion The candidate ion that is selected for the TOF
MSMS experiment.
Declustering The declustering potential parameter controls the
potential voltage on the orifice. It is used to minimize the
solvent clusters that might remain on the sample
ions after they enter the vacuum chamber, and, if
required, to fragment ions. The higher the voltage,
the higher the energy imparted to the ions. If the
DP parameter is too high, then unwanted
fragmentation might occur.
DP spread The DP spread parameter (DPS), in conjunction with
the declustering potential (DP), determines the
declustering potential applied to the ions. The
declustering potential is ramped from low to high
declustering potential. For example, in positive
mode, the declustering potential is ramped from
DP – DPS to DP + DPS. By entering a DPS value,
declustering potential spread is automatically
activated.
Collision energy The collision energy is the difference between the
entrance potential (Q0) and the voltage on the
collision cell quadrupole (Q2). In MS/MS scans, the
collision energy provides the energy for collision
activated dissociation (CAD). The collision energy
is compound-dependent; that is, the optimum value
varies from compound-to-compound.
System User Guide
RUO-IDV-05-2334-E
Operating Instructions Software
Experiment
TOF MS, TOF MSMS, Q1, IDA, SWATH,
MRM HR
TOF MSMS, IDA, SWATH, MRM HR
TOF MS, TOF MSMS, Q1, SWATH, MRM
HR
TOF MS, TOF MSMS, IDA, SWATH, MRM
HR
TOF MS, TOF MSMS, SWATH, MRM HR,
IDA
SCIEX X500 QTOF System
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