Isotope ratio measurements with a fully simultaneous Mattauch-Herzog ICP-MS.

A fully simultaneous ICP-MS, based on a compact Mattauch-Herzog geometry with a permanent magnet and a large, spatially resolving semiconductor ion detector covering the complete inorganic relevant mass range from (6)Li to (238)U in a single measurement, has been used to determine isotope ratios and assess achievable isotope ratio precisions. Measurements of the (235/238)U isotopic ratio, chosen as example for an isotopic system with a disparate isotope ratio, yielded a precision of 0.05 % relative. To evaluate the expected multi-isotope ratio measurement capabilities of the system used, several isotope ratios spanning a wide range ((6/7)Li, (84/86)Sr, (87/86)Sr, (88/86)Sr, (204/207)Pb, (206/207)Pb and (208/207)Pb) were measured simultaneously, using a synthetic multi-element standard as sample. Very satisfying isotope ratio precisions, between 0.5 and 0.04 % relative, depending on the isotope ratio in question were found during the simultaneous multi-isotope ratio measurements. Together with a brief description of the system and measurement procedures employed for this technical note, the results achieved are assessed in view of other existing ICP-MS-based isotope ratio techniques.