The TSQ Series II mass spectrometers have three rod assemblies. The first and third rod assemblies, Q1 and Q3, are hyperbolic quadrupoles. The second rod assembly (Q2) is a square-profile quadrupole. Rod assemblies can operate in either of two modes:
- As ion transmission devices
- As mass analyzers
If you apply only RF voltage, a rod assembly serves as an ion transmission device that passes all ions within a large range of m/z values (that is, virtually all ions that are present).
When you apply both RF and DC voltages to a rod assembly, ions of different m/z values have different stability profiles. This difference in stability allows the rod assembly to act as a mass filter.
On the MS, the quadrupole rod assemblies can operate with both RF and DC voltages or with only RF voltage. That is, Q1 and Q3 can act as either mass analyzers or ion transmission devices. The Q2 rod assembly operates exclusively with RF voltage. Therefore, Q2 is always an ion transmission device.
Summary of the quadrupole modes for the various scan types
The following table provides a summary of the quadrupole modes by scan type.
Scan type | Q1 quadrupole | Q2 collision cell | Q3 quadrupole |
|---|---|---|---|
Full scan (Q1) | Scan1) | Pass all ions2) | Pass all ions |
Full scan (Q3) | Pass all ions | Pass all ions | Scan |
SIM scan (Q1) | Set3) | Pass all ions | Pass all ions |
SIM scan (Q3) | Pass all ions | Pass all ions | Set |
Product ion scan | Set | Fragment ions; then pass all fragments | Scan |
Precursor ion scan | Scan | Fragment ions; then pass all fragments | Set |
Neutral loss scan | Scan | Fragment ions; then pass all fragments | Scan |
SRM scan | Set | Fragment ions; then pass all fragments | Set |
QED | Set | Fragment ions; then pass all fragments | Set4) |