Detection is by electron multiplier coupled to multichannel analyser. Dry laser generated samples are handled in the same way except that the aerosol passes directly into the plasma without passing through the spray chamber or nebuliser. An extended dynamic range is available with these instruments wherein elements can be analysed over a concentration range of over ten orders of magnitude. The mass analyser most often used in ICP-MS is the quadrupole mass filter. Quadrupole mass spectrometers are compact and easy to use with an ICP ion source but their relatively low resolution is insufficient to separate different ions at the same mass to charge ratio.
Polyatomic ions can overlap with analyte ions causing severe interferences in some cases.
The use of a double focussing sector mass analyser to separate out the ions can provide the necessary resolution to separate the more severe polyatomic ion interferences. The maximum accelerating voltage is 8kV. It should be noted that a spectral resolution of roughly 10,000 would alleviate most polyatomic ion interferences but much higher resolution would be required to separate different atomic ions at the same nominal charge to mass ratio.