Q1Ms And Q3Ms Scan Modes - Thermo Scientific TSQ Series Hardware Manual

1
Introduction
Scan Modes
If only RF voltage is applied, a rod assembly serves as an ion transmission device that passes all ions
within a large range of mass-to-charge ratios (that is, virtually all ions present).
When you apply both RF and dc voltages to a rod assembly, the separation of ions of different
mass-to-charge ratios occurs. This separation allows the rod assembly to serve as a mass analyzer.
On the TSQ mass spectrometer, the quadrupole rod assemblies can operate with RF and
dc voltages or with only RF voltage. That is, Q1 and Q3 can act either as mass analyzers or ion
transmission devices. The Q2 rod assembly operates exclusively with RF voltage. Thus, Q2 is
always an ion transmission device. For a summary of how the rod assemblies function in several of
the major scan modes, see
.
Table 1. Summary of scan modes
Scan mode
Q1MS
Q3MS
Product
Parent
Neutral Loss
a
Scan = full scan or transmission of selected ions
b
Pass all ions or fragments = pass ions or fragments within a wide range of mass-to-charge ratios
c
Set = set to pass ions of a single mass-to-charge ratio or a set of mass-to-charge ratios
d
Fragment ions = collisions with argon gas cause ions to fragment

Q1MS and Q3MS Scan Modes

The Q1MS and Q3MS scan modes perform only one stage of mass analysis. The mass spectrum
obtained is equivalent to the mass spectrum obtained from an instrument with a single mass
analyzer. In the one stage of analysis, ions formed in the ion source enter the analyzer assembly.
One of the mass analyzers (Q1 or Q3) is scanned to obtain a complete mass spectrum. The other
rod assemblies (Q2 and Q3, or Q1 and Q2, respectively) act as ion transmission devices. In the
Q1MS scan mode, Q1 is used as the mass analyzer; in the Q3MS scan mode, Q3 is used as the
mass analyzer.
4 TSQ Series Hardware Manual
Table 1.
Q1 quadrupole Q2 collision cell
a
Scan Pass all ions
Pass all ions Pass all ions
c
Set Fragment ions
Scan Fragment ions, then pass all fragments
Scan Fragment ions, then pass all fragments
b
d
, then pass all fragments
Q3 quadrupole
Pass all ions
Scan
Scan
Set
Scan
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