Fisons - PQ ExCell
( Thermo Scientific )

Quadrupole ICP-MS instrument with Collision Cell Technology

Introduced in 1999, the PQ ExCell was packaged in the same cabinet as the PQ3 but the addition of the infinity lens and the Peltier cooled sample introduction system made a considerable improvement to the instrument's sensitivity and background. The infinity lens consists of a hexapole ion guide biased by mass dependent RF voltages that optimize ion transmission across the mass range. A chicane deflector replaced the photon stop in the lens optics that helped maintain maximum ion current from sampling interface to electron multiplier. Instrument sensitivity was at least 30 Mcps/ppm for Lithium and Uranium and 60 Mcps/ppm at Indium. Since the ExCell's background was typically less than 0.5 cps, the signal to noise ratio had been improved by a factor of 20 compared to the PQ3. Additionally, the infinity lens could be pressurized with a gas such as helium allowing for collision cell experiments. The introduction of a collision gas reduces typical argon-based interferences that make the analysis of some elements difficult.
The standard ExCell came with all the PQ3 improvements in addition to the new Peltier cooled spray chamber and the infinity lens without the collision cell components, which were available as an option.