Multicollector-Inductively Coupled Plasma Mass Spectometer (MC-ICP-MS)

The Thermo Scientific Neptune XT multi-collector ICP mass spectrometer is an instrument developed for high-precision isotopic analysis of metals, metalloids and some non-metals. The instrument is therefore equipped with a robust and efficient ion source (the ICP, or inductively coupled plasma), a double-focusing sector-field mass spectrometer with Nier-Johnson geometry for separation of the ion beams based on the ratio of mass to charge of the respective ions and an array of 9 faraday cups for simultaneous monitoring of the selected ion beams. Under ideal conditions, a measurement precision of up to 0.001% relative standard deviation (RSD) can be obtained. Compared to previous equipment, the device offers, among other things, an increased mass resolution (resolving power up to 15000) and faraday cup amplifiers with a 10¹³ instead of the standard 10¹¹ Ohm resistance, which allows reliable measurement at lower element concentration. All elements with U+22652 isotopes show natural variation in their isotopic composition due to isotope fractionation. Isotope fractionation is a consequence of the fact that U+2013 mainly as a result of their difference in mass U+2013 the isotopes of an element do not necessarily participate with exactly the same efficiency in physical processes and (bio)chemical reactions. Isotope fractionation can be controlled both kinetically and thermodynamically. The Thermo Scientific Neptune XT provides the necessary precision to detect and quantify the resulting differences in the isotopic composition of an element. This high-precision isotopic analysis is used in the context of scientific research in a wide variety of domains: geo- and cosmochemistry, environmental studies, archaeometry and the biomedical sciences. Such analysis can be used, for example, to unravel or reconstruct geological (e.g. ore formation) and (bio)chemical processes. It is also a powerful tool for determining origin, e.g. of the raw materials used in the manufacture of archaeological artefacts, of food products of plant or animal origin, of human remains or of chemical pollution. Changing the isotopic composition of essential mineral elements in body fluids and tissues under the influence of a disorder can provide insight into the biochemical processes involved and contains diagnostic and/or prognostic information. In addition, a limited number of elements also show natural variation in their isotopic composition due to the presence of one or more radiogenic nuclides, these are nuclides that are reshaped in function of time as a result of the decay of a naturally occurring and long-lived radionuclide. In addition to the above-mentioned applications, isotopic analysis of such elements can also be used for geochronology.
To achieve the highest accuracy and precision, the analyte element for measurement must be chromatographically isolated from the matrix, unless standards with exactly the same matrix composition are available. Combination with laser ablation as a sample introduction technique allows in some cases (e.g. glass) direct isotopic analysis of solid material.