ORS can be operated without using highly reactive gases. Octopole design allows higher cell pressures increasing reaction cross section due to better ion beam focussing
He Mode
Collisionally Induced Dissociation – the interference is broken apart when it impacts the He atom
Energy Discrimination – the larger polyatomic species (greater ionic radii) loose more energy than the smaller analyte species and cannot enter the QP – effectively a molecular filter
Aided by the Agilent ShieldTorch System – all ions enter the Octopole with well-defined narrow energy distribution
H2 Mode
Charge Transfer – electron transferred from (or to) hydrogen, producing a neutral species
Actually both modes use Energy Discrimination, at least in part