The presented results contain raw data of magnesium and calcium quantification in the studied solutions using Indiko Analyzer and NexION 300D mass-spectrometer as well as results of isotope ratio analysis obtained using Nu Plasma II mas-spectrometer.
The collected samples were analyzed using a discrete analyzer Indiko Plus Clinical Chemistry Analyzer (Thermo Fisher Scientific, Vantaa, Finland). Calcium and magnesium concentrations were determined spectrophotometrically according to the procedure described in the ISO/TS 15923-2:2017 Water quality – Determination of selected parameters by discrete analysis systems – Part 2: Chromium(VI), fluoride, total alkalinity, total hardness, calcium, magnesium, iron, iron(II), manganese and aluminium with photometric detection.
The isotope ratios of Mg were measured using MC-ICP-MS in a dry mode with ion chromatograph applied for sample introduction. A sample aliquot was introduced to the ion chromatograph (Dionex ICS-5000+, Thermo Scientific, Dreieich, Germany) equipped with inorganic cation exchange column IonPackC16 (3 × 250 mm, 5 µm) and a guard column IonPack CG16 (3 × 50 mm). The column eluent was passed through the self-regenerating suppressor (CDRS 600, 2 mm), a conductivity detector and then was carried through to a six-port valve to the desolvation nebulizer. By changing the position of the valve, only the column fraction corresponding to Mg elution (retention time between 7.0 and 9.5 min) was directed to the plasma. The bracketing solution of Mg (DSM3) was pumped toward desolvation nebulizer unit before and after the chromatographic peak of Mg at the same flow rate. Aridus II desolvation nebulizer (CETAC Technologies, Omaha, NE, USA) was applied. Plasma II (Nu Instruments, Wrexham, UK) multi collector inductively coupled plasma mass spectrometer was used for isotope ratio analysis. A transient signal of Mg eluted from the column (retention time around 7.8 min) was registered and the total peak area was integrated. Magnesium isotope fractionation in the analyzed samples was calculated as a delta-value.
