For isotope analysis ALS Scandinavia uses different forms of ICP-MS, i e mass spectrometry with an inductively coupled plasma as the ion source. The plasma is formed by argon gas flowing through a radio- frequency field. Among the advantages of ICP is the ease of sample introduction. Especially, solutions can be introduced continuously since the plasma operates at atmospheric pressure.

ICP-SFMS

In this technique, a magnetic sector is used as the mass analyzer (SF = sector field), which distinguishes ICP-SFMS from the more common quadrupole ICP-MS (ICP-QMS). The sector technique is also called High-Resolution ICP-MS because of the higher mass resolution of the magnetic sector compared to the quadrupole. The precision in isotope ratio measurements by ICP-SFMS under optimum conditions is better than 0.05% relative standard deviation.

MC-ICP-MS

ALS Scandinavia has also access to a multicollector ICP-MS instrument for high precision isotope ratio measurements. In this technique, mass separation is based on a magnetic sector like in ICP-SFMS. Higher precision is made possible by simultaneous measurement of the isotopes by individual detectors. Isotope ratio precision down to 0.001% (=10 ppm) relative standard deviation can be achieved.