ICPMS

Inductively Coupled Plasma Mass Spectroscopy (ICP-MS)

ICP-MS is a destructive, mass spectroscopy technique used to make qualitative or quantitative measurement of the elemental composition of a sample.

In conventional Inductively-Coupled Plasma Mass Spectroscopy (ICP-MS), an inert gas is inductively heated by current flow through a surrounding electromagnetic coil to form a plasma. The sample (typically in liquid form) is digested by the plasma into isolate ion fragments, which are accelerated through a mass analyzer to generate a mass spectrum.

In the plasma, there is no net electronic charge: free electron radicals generated by the plasma are in equilibrium with the positively charged atoms they vacate. The sample is introduced to the plasma through a nebulizer that sprays the sample, as a liquid, and ultrasonicates it to produce a fine mist. The high kinetic energy of charged particles within the plasma decompose the sample analyte into its constituent elements and ionizes the resulting atoms. A quadrupole mass analyzer separates the ions according to their mass / charge (m/z) ratio, producing an elemental mass spectrum.

ICP-MS is distinct from GC-MS in that more specifically analyzes elemental composition versus compounds in an organic mixture. It can be used on a wider variety of sample types and achieves improved detection limits for trace elemental contaminants.

Application Areas for ICP-MS

ICP-MS is used in geochemical characterization, and as a quality assay for pharmaceuticals and biomedical research, metallurgy, and toxicology. Due to its profound sensitivity for trace materials, it has also been used in forensic analysis.

Measurements from ICP-MS

  • Bulk elemental composition (liquids, aqueous solutions)
  • Isotope analysis

USES & LIMITATIONS FOR ICP-MS

  • What it is great for:
    • Identification and quantification of trace elements
    • Contamination and impurity detection
      (sensitivity limit is on the order of parts-per-trillion)
  • Limitations:
    • Quantification requires parallel analysis of reference / control
    • Destructive