In-situ Sr isotopic measurement of natural geological samples by LA-MC-ICP-MS
地质样品Sr同位素激光原位等离子体质谱(LA-MC-ICP-MS)测定

Strontium (Sr) isotopes are important indicators and tracers in deciphering the sources and evolution of magmas. Since the development of multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS), in-situ Sr isotopic analyses in high spatial resolution have become widely available and feasible for minerals with high Sr concentrations. We developed in-situ Sr analytical procedure on Netptune MC-ICP-MS coupled with 193 nm excimer laser, based on systematical analysis of porites coral, plagioclase, apatite and pervoskite. It is shown that the interferences of Kr, Rb and REEs can be reasonably corrected, and that the interferences of Ca argide/dimmer species are limited in our Neptune instrument. Analysis with spot size of 63, 94 and 127μm and different repetition rates shows that the larger pit size produces the higher signal intensity, hence higher precision of Sr isotopic data, however, the repetition rate does not have a significant influence on the precision.