We have a number of mass spectrometers in our group, three of which have been modified in-house. All are quadrupole time of flight mass spectrometers.
Ion Mobility Capable Q-ToF – ‘The MoqToF’
This instrument was developed in our group by Bryan McCullough in collaboration with Dr Paul Kemper (UCSB) and Micromass Ltd (Manchester, UK). It is based on a commercial Micromass QToF 1 instrument customised to allow ion mobility mass spectrometry experiments. Instrument has been fitted with the temperature controlled drift cell (5.1 cm) in between source hexapole and quadruple analyser. The drift cell ion optics feature a pre-cell three element Einzel lens and short post cell hexapole. The Drift cell is located in its ow chamber, and independently pumped by 500 ls-1 turbomolecular pump and a Edwards 40 rotary, coupled to a roots blower. Pressure of inert gas (helium) in the drift region is typically 3.5-4 Torr while applied electric field are between 2 and 10 V.cm-1.
Under these conditions we are able to detect protein ions with resolution up to 20. Our protein conformation studies often include experiments at reduced or elevated temperatures. During low temperature experiments (down to 100 K) cooling is achieved by flowing coolant gas through the cooling block of the drift cell. Experiments at elevated temperatures (up to 600 K) can be performed with use of internal electric heaters.
Ultima – QToF
Principally used for large complexes and for oligomer analysis.
High Resolution Ion Mobility Capable QToF – J2
This instrument is currently under development. It is based on Micromass QToF2 and will feature drift cell (50 cm) located directly after Z-Spray source. Pre and post drift ion funnels have been designed to maximise ion transmission. Drift region will include ion gates which will enable IMS-IMS experiments. Pressure range will be between 1 and 5 Torr while applied electric fields between 2 and 20 V.cm‑1. Our goal is to achieve resolution of 100. A dynamic design of the assembly will allow for uniform thermal expansion and contraction during temperature controlled experiments between 90 and 600 K.
Waters Synapt G2
Recently our group acquired a Waters Synapt G2. This commercial travelling wave ion mobility mass spectrometer offers high efficiency ion mobility separation and high resolution mass spectrometry.