Determination of Osmium and Osmium Isotope Ratios by Microelectrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry

A new merging introduction technique has been developed for Os analysis with inductively coupled plasma mass spectrometry (ICP-MS). The sample was placed in a microheater cell in a merging chamber and vaporized OsO₄ was carried to the ICP with a blank matrix mist flow sprayed from a nebulizer. In the merging introduction, the best operational parameters could be obtained by the usual optimization using a standard solution. The ¹⁸⁷Os/¹⁸⁶Os ratio and the Os abundance were measured simultaneously by spiking ¹⁹²Os. The precisions of the ratio and abundance measurements using 0.8 ng of Os were 5 and 4%, respectively. The detection limit of Os by this method was lower than 100 fg, which is almost one-tweifth of that obtained by conventional nebulization introduction.