ICP Inductively Coupled Plasma | Specialty Gases | Coregas NZ

ICP inductively coupled plasma

ICP laboratory instrumentation is used in contract laboratories for the analysis of water samples. The technique requires high purity specialty gases argon to create the high temperature plasma.

When it comes to the analysis of trace amounts of rare earth elements (REEs) in a sample such as groundwater or drinking water, ICP-MS is becoming an industry standard. ICP-MS uses 5.0 grade argon gas to both carry the sample and form a plasma flame which exists at between 6,000 and 10,000°C. The sample is passed into the plasma where it is ionised and the ensuing ions are then measured in a mass spectrometer.

The ICP-MS technique has superior detection capability to its sister technique ICP-AES, where an atomic emission spectrometer is used instead of the mass spectrometer for ion characterisation. ICP-MS has a higher throughput than a graphite furnace atomic absorption spectrometer (GFAAS) at similar, or better detection limits. It is also less vulnerable to matrix effects than these alternative techniques due to the very high plasma flame temperature.

The main limitation of the technique is that the plasma tends to produce positive ions, so species that predominantly form negative ions such as chlorine, iodine and fluorine are difficult to detect with ICP-MS.

Another notable technique for similar work is the flame atomic absorption spectrometer for flame AAS. Similar to the ICP method, it has earned its place in environmental and food testing laboratories to detect metals in water, soil and food samples.

Product selection

An ICP instrument consumes large quantities of argon gas. Supply from single cylinders is possible if an automatic changeover is used to ensure supply continuity between cylinders. Use of a 6-pack or 12-pack of cylinders is also common.