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)
- Quantification requires parallel analysis of reference / control