Commercial manufacturers offer several variations on and modifications of these approaches. Perkin Elmer's ELAN 6000 and Fisons' PlasmaQuad III provide dual mode in a single detector that determines high and low concentrations in a single run and detects transient peaks. With the addition of an autosampler and an autodilutor, the UltraMass can then automatically dilute samples that show high concentrations of target elements and reanalyze. Thermo Jarrell Ash takes a different strategy with Quadrion by adding an optical emission spectrometer accessory to create an instrument that prescreens samples for concentration range. Or the analyst can set up criteria by which to select either optical or mass analysis based on a particular element or concentration range.
All instruments come with a conventional nebulizer for liquid samples.
As a rule, problems develop when total dissolved solids in samples exceed 0.1-0.5. The problem manifests itself in the orifices leading into the mass spectrometer. Ions enter the mass spectrometer through two sequential orifices, the sampler and skimmer cones. In effect, these are controlled leaks against which the vacuum pumps must work to maintain a good vacuum to minimize unwanted background ions. The sizes of these orifices also affect the ratio of analyte ions to oxide interferences.