4 Types of ICP-MS Interferences

Joe writes...
I have a question about interferences on ICP-MS. I have tried to induce interferences using 6020ICS-0A at 1:10 and 1:100 dilution. I have been looking for interferences with Cu, As, Zn, and Cr. 6020ICS-0A has many of the interfering components for these metals, but I can't induce the interferences at these spike levels. My questions are: 1) Just because an interferent is present, if the instrument is tuned correctly, is the interferent going to always have an effect or do other factors have to also be present? 2) What would these other factors be?

Dear Joe,

I haven't heard from you in a while. I hope things are well. The answer depends upon the type of interference. The types are:

  • Direct mass overlap: In this case, there is an isotope of an element that is equal to the mass of the analyte. This type of interference does not go away or change much relative to the analyte signal.
  • Double ions: This is dependent upon instrumental parameters and the elemental source of the double ion.
  • Molecular species: This is dependent upon instrumental parameters and the chemistry of the species involved.
  • Abundance sensitivity: This type is dependent upon ion optics tuning/mass tuning, and species and upon which mass side of the analytical signal the abundant species presents itself.

I have found that factors such as power, ion optical settings, nebulizer type and sample argon flow rate, as well as matrix components (amount and average atomic number of matrix components) all influence the interference effect.

If you are not seeing certain types of interference, it may well be due to the fact that your instrumental parameters are optimal.

Serving you in chemistry,
Paul R. Gaines Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist

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