Building B, Room B232
ICP-MS (Inductively Coupled Plasma Mass Spectrometry) or plasma source mass spectrometry represents the most sensitive and flexible method for the analysis of mass fractions of trace elements in geomaterials (rocks, minerals, water) and in chemical or technical products. The advantage of the method lies in the nearly complete ionization of many elements, which is achieved by using argon plasma at temperatures of up to 7000°C and fast data acquisition.
The Thermo Electron Element XR in the AB Geochemistry (installation 3/2006) is a high-resolution double focussing instrument which provides directional (magnet) and energy focussing (electrostatic sector) of ion beams. Only ions of particular energy and mass/charge can enter the ion collection device, which, permits high mass resolution and removal of interferences. The instrument has three mass resolution settings that can be set by movable entry and exit slits. Ion collection normally uses a discrete dynode electron multiplier, which can be used in pulse counting and analog mode, thus covering signal intensities across a range of up to nine orders of magnitude.
Sensitivity of the instrument is typically around 1 million cps (counts per second) for a 1 ng/g solution of the element indium (mass 115In). Detection limits of many elements are in the pg/g to fg/g range. With different types of sample introduction systems, sensitivities of some elements can be improved further. For instance, desolvation systems (e.g. Aridus) not only increase the sensitivity of some elements, they also reduce the influence of interfering molecules on analyte masses.
Our analytical focus and expertise has been analyses of mass fractions of trace and ultra-trace elements in terrestrial and extraterrestrial materials by isotope dilution coupled with ICP-MS. Elements include platinum group elements, but also Re, Au, Ag, S, Se, Te, Cu, Cd, In, Tl and more abundant trace elements such as the rare earth elements. Other applications include main and trace cations in surface water and in carbonate sediments, trace elements in basic and ultrabasic rocks.
Contact: PD Dr. J. Elis Hoffmann
Lab course ICP-MS:
Once per year, typically in the fall semester, we offer a lab course „Einführung in die Plasmaquellenmassenspektrometrie“ (see FUB course listings). This course presents basics of the method combined with lab work and is open to B.Sc., M.Sc., and doctoral students.
|Element XR with laminarflow-workbench
|Aridus-Desolvationsystem (bottom right)
|exhaust system for the ICP-MS
|liquid-Ar-tank with backup-system