Calcium Carbonate and Phosphate Reference Materials for Monitoring Bulk and Microanalytical Determination of Sr Isotopes

In situ laser ablation analyses rely on the microanalytical homogeneity of reference materials ( RM s) and a similar matrix and mass fraction between unknown samples and RM s to obtain reliable results. Suitable carbonate and phosphate RM s for determination of Sr isotope ratios in such materials are limited. Thus, we determined 87 Sr/ 86 Sr ratios of several carbonate ( JC t‐1, JC p‐1, MACS ‐1, MACS ‐3) and phosphate ( MAPS ‐4, MAPS ‐5, NIST SRM 1400, NIST SRM 1486) international RM s using dissolved samples and two different multi‐collector inductively coupled plasma‐mass spectrometers ( MC ‐ ICP ‐ MS ). Our Sr isotope data are in agreement with published data and have an improved measurement precision for some RM s. For MACS ‐1, we present the first 87 Sr/ 86 Sr value. We tested the suitability of these materials for microanalytical analyses by LA ‐ MC ‐ ICP ‐ MS , with two different laser ablation systems: a conventional nanosecond laser and a state‐of‐the‐art femtosecond laser. We investigated the RM s micro‐homogeneity and compared the data with our solution data. Both laser ablation systems yielded identical 87 Sr/ 86 Sr ratios within uncertainty to the solution data for RM s with low interferences of REE s. Therefore, these carbonate and phosphate RM s can be used to achieve accurate and precise results for in situ Sr isotope investigations by LA ‐ MC ‐ ICP ‐ MS of similar materials.