Categories of exhibits
Quadrupole ion trap & detector
Exhibit no. 493
The quadrupole ion trap is an ion storage and mass analysis device, which consists of a ring electrode and end two cap electrodes manufactured to very high standards. The end cap electrodes have small perforations in the center to allow the ions to enter and exit the ion trap. Trapped ions can be controlled by changing the main RF drive voltage on the ring electrode, applying external DC voltages to the ring electrode, supplying auxiliary AC signals to the endcap electrodes, or employing a combination of these signals simultaneously. Helium gas is usually introduced into the ion trap for efficient trapping and cooling of the ions; it also serves as a collision gas during tandem mass spectrometry.
The exhibit is a quadrupole ion trap and detector assembly from Esquire 2000 ion trap mass spectrometer for LC/MS manufactured by Bruker Daltonics around 2000. The end of the ion transport optics extended directly to the outside of the inlet end cap of the ion trap. The detector was a conversion dynode/electron multiplier system that also included a lens system to focus the ions toward the detector. A polarity switchable conversion dynode allowed for the detection of both positive and negative ions while the voltage on the electron multiplier was kept at a constant negative value.
