Measurement of 87Sr/86Sr in limestones after acid leaching and direct injection in a liquid chromatograph coupled to a multicollector ICP-MS

• Published in: Journal of analytical atomic spectrometry Vol. 37; no. 1; pp. 194 - 202
• Main Authors: Puente-Berdasco, B, Rodríguez, J, Ballesteros, D, Painchault, A, Nehme, C, Mouralis, D, Gil-Ibarguchi, J I, Martín-Izard, A, Garcia Alonso, J I
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 01.01.2022
• Subjects: Acid leaching; Carbonates; Cation exchanging; Chromatography; High performance liquid chromatography; Inductively coupled plasma mass spectrometry; Isotope ratios; Nitric acid; Reference materials; Separation; Stratigraphy; Strontium; Strontium 87; Strontium isotopes
• DOI: 10.1039/d1ja00340b
• ISSN: 0267-9477

A procedure for the measurement of 87Sr/86Sr in carbonates without off-line strontium separation was developed, validated and applied to Normandy chalkstones. The method is based on the injection of the dissolved/leached sample into a high-performance liquid chromatography (HPLC) system directly coupled to a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). Matrix and spectral (Ca, Rb) interferences were removed by an on-line separation procedure based on cation exchange chromatography using 1 M nitric acid as an eluent in the presence of 3.8 mM 18-crown-6. The main polyatomic interferent was identified as NO2Ca+, affecting mass 86 of strontium. Isotope ratios were calculated by multiple linear regression from the measured chromatographic peaks. The method was evaluated using a NIST 987 Sr isotope reference material and subsequently validated employing a JCp-1 coral reference material in comparison with the traditional off-line separation procedure. Finally, the method was applied to ten Normandy limestones (chalkstones) with results in agreement with the expected values based on geological, geochemical, and stratigraphic studies.