Why ICPMS

ICPMS is used for elemental determinations. Geochemical analysis labs were early adopters of ICPMS technology because of its superior detection capabilities, particularly for Rare-Earth Elements (REEs). ICPMS has many advantages over other element analysis technique such as atomic absorption and optical emission spectrometry, ICP Atomic Emission Spectroscopy (ICP-AES). The advantages of ICPMS are:

• Better detection limits and higher throughput compared to Graphite Furnace Atomic Absorption Spectroscopy (GFAAS).
• Ability to handle both simple and complex matrices with minimum matrix interferences due to the high-temperature of the ICP source.
• Superior detection capability to ICP-AES with same sample throughput
• Ability to obtain isotopic information

How ICP-MS Works

An ICPMS combines a high-temperature ICP (Inductive Coupled Plasma) source with a mass spectrometer. The ICP source converts the atoms of the elements in the sample to ions. These ions are then separated and detected by the mass spectrometer.

The liquid sample is typically introduced into the ICP plasma as an aerosol, which is generated in a stream of argon (Ar) contained in a quartz tube or “torch”, either by aspirating a liquid or dissolved solid sample into a nebulizer or using a laser to directly convert solid samples into an aerosol. Once the sample aerosolis introduced into the ICP torch, it is completely desolvated and the elements in the aerosol are converted first into gaseous atoms and then towards the end of the plasma.

Once the elements in the sample are converted into ions, they are then brought into mass spectrometer via the interface cones. This is done through the intermediate vacuum region created by the two interface cones, the sampler and the skimmer.

The ions from the ICP source are then focused by the electrostatic lenses in the system. The ions coming from the system are positively charged, so the electrostatic lens, which also has a positive charge, serves to collimate the ion beam and focus it into the entrance aperture or slit of the mass spectrometer. Once the ions enter the mass spectrometer, they are separated by their mass-to-charge ratio.

Applications

ICPMS is used in the following areas:

• Medical and forensic field, specifically Toxicology
• Environmental field
• Industrial and biological monitoring
• Flow cytometry