All data were obtained using MC-ICP-MS (Multi-Collector Inductively Coupled Plasma Mass Spectrometry). Measurements were performed with a Nu Instruments Plasma 3 mass spectrometer. The sample introduction system consisted of a Cetac Aridus 3 desolvating nebulizer, operated at a flow rate of 50 or 100 μL/min.
The analyzed solutions were mixtures of an isotopic standard of a multi-isotopic element (e.g., NIST SRM 987, NIST SRM 981) and a custom-made mixture of two mono-isotopic elements, such as Nb/Y, Bi/Au, or Ho/Tm.
Some of the data files contain results from experiments performed using the internal standard method, in which the internal standard was a mixture of two mono-isotopic elements (e.g., Nb and Y), while the analyte was an element with a known isotopic composition (e.g., Sr).
Another set of results was obtained using the ORM (Optimised Regression Model) method, which involves the measurement of isotopic ratios under variable plasma power conditions. In this case, the calibrator was a pair of mono-isotopic elements, and the analyte was a multi-isotopic element with a known isotopic ratio (e.g., Sr, NIST SRM 987).
The file name corresponds to the name of the analyzed standard or sample. If an additional note in the format “1350” or "1425" appears in the name, it indicates the RF power that was used. This makes it easy to distinguish files with the same base name but different applied measurement conditions (e.g., “Nb_1400” vs. “Y1375” – in the first case, it is a measurement of the niobium standard at RF power of 1400 W, while in the second, it is an analysis of the yttrium standard at 1375 W).
