Inductively coupled plasma mass spectrometry
Mass spectrometry with inductively coupled plasma (English inductively coupled plasma mass spectrometry, ICP -MS) is a robust, highly sensitive mass spectrometric analysis method in the inorganic element analysis. It is used inter alia for trace analysis of heavy metals, such as mercury, lead or cadmium.
In the ICP -MS ionized argon is induced first by a high-frequency current and the sample heated at 5,000-10,000 ° C. The atoms are ionized and a plasma is formed. Then generated in the plasma ions are accelerated by an electric field in the direction of the analyzer of the mass spectrometer. There, the individual elements and their isotopes are detected by measurement.
With the detection limit of ICP-MS in the range of nanograms per liter ( ng / L ), or better achieved for most of the elements of the periodic table. Furthermore, the method for the quantitative determination is characterized by an extremely high linear region up to nine orders of magnitude ( from grams to picograms per liter). In addition to quantitative analytical tasks can also be operated a high-precision isotope analysis with ICP -MS. For this purpose, high-resolution ICP- mass spectrometers are often used.
By coupling with analytical separation methods such as high performance liquid chromatography, gas chromatography, capillary electrophoresis, gel electrophoresis, ion exchange chromatography and field-flow fractionation, the ICP -MS can also be used for speciation analysis. In addition, solid samples can be analyzed directly by coupling with a laser ablation device. Thus, a spatially resolved, quasi non-destructive analysis is possible for example to historical items.
Alternative methods
Other important methods for elemental analysis are:
- Optical emission spectrometry with inductively coupled plasma ( ICP -OES)
- Instrumental neutron activation analysis ( INAA )
- X-ray fluorescence analysis ( XRF)
- Atomic absorption spectrometry ( AAS)