ICP – MS provides trace element concentrations in ppb and sub- ppb level concentrations. The analysis normally requires dissolution of solid sample in solution prior to analysis. The article reviews three innovative options that expand the applications many fold and contribute significantly to the laboratory throughput.
Collision cells for removal of polyatomic species
ICP – MS interferences and their removal discussed the common interferences encountered in ICP – MS analysis.
Polyatomic interferences are removed by making use of collision cells which are based on controlled reaction between reactive gases and the analyte isotopes. Each reaction gas reacts selectively with certain polyatomic species while others remain and lead to residual interferences. Different collision cell configurations are available through different manufacturers. Perkin Elmer collision cells are based on quadrupoles whereas Agilent uses octopole based reaction systems with improved ion focusing and increased collision efficiency
Dual View ICP
Conventionally radial view ICP torches are in use. In the axial view arrangement the system views the plasma over its axial length, i.e, over a longer path than radial view only systems. This results in 5– 10 fold improvement in detection limits. On the other hand radial viewing of plasma permits analysis at higher concentrations. Some manufacturers provide both viewing options thereby permitting working over a large sample concentration range without the need for serial dilutions.
Laser ablation extends ICP – MS analysis to analysis of solid samples without the need for sample digestion. It is a process involving removal of material from a surface by irradiation with a laser beam. The material on heating by the laser beam evaporates or sublimates and is led directly into the plasma of the spectrometer. The system is computer controlled by real-time video imaging system capable of providing the elemental composition map of the sample surface. The accessory can be used for samples originating from materials science, biological, geological, archaeological and environmental sources.