Strontium Isotope Geochemistry

Stable strontium isotope fractionation in hydroponically grown mung and soy bean sprouts

Journal of Food Composition and Analysis, doi:10.1016/j.jfca.2022.105081

Plant utilization is one of the essential processes dominating the migration, distribution, and accumulation of metals in the critical zone. Defining the isotopic fractionation factor of metals during plant utilization aims to constrain the plant fluxes during metal cycling, especially under different climatic conditions. The KBSI (Korea Basic Science Institute) has mature techniques for hydroponic experiments, and the NCKU NSI team has robust techniques for acid digestion and matrix separation of organic materials and high precision stable Sr isotopic determination . This research collaboration suggests that the changes in the Sr isotope composition of the plants are due to the combination of mixing and isotope fractionation processes between bean seeds and nutrient solution, providing an important inside into the Sr isotope behavior during the growth of plants.

Strontium Isotope Geochemistry

Adsorption and Desorption Behaviors of Sr on Montmorillonite: A Triple Sr Isotope Perspective

ACS Earth and Space Chemistry, doi:10.1021/acsearthspacechem.2c00222

Montmorillonite is a widespread mineral, which affects the migration of Sr in the critical zone. Hydrochemical factors influencing Sr adsorption have been evaluated in the literature through laboratory batch experiments. Since those experiments were conducted using high-concentration and high-purity standard solutions, the influences of chemical matrices or element relative concentrations in water remain unclear. Here, we reassessed the adsorption and desorption behaviors of Sr on montmorillonite using natural waters with various chemical matrices and ionic strengths. The triple Sr isotopic tracers provide perspectives on how montmorillonite minerals adsorb Sr and release it to aqueous environments at various hydrochemical conditions.

Core Technique
Precise δ^88/86Sr determination on MC-ICP-MS by an improved method combined Zr-empirical external normalization isobaric interference correction and ⁸⁴Sr-⁸⁷Sr double spike

Journal of Analytical Atomic Spectrometry, doi:10.1039/D1JA00224D

The most accurate and precise δ^88/86Sr determination is performed by using the double spikes (DS) technique on TIMS. However, TIMS is always subjected to its long data acquisition time over MC-ICP-MS. We present a novel approach, combing the use of Zr-EEN for Kr and Rb isobaric interference correction and ⁸⁴Sr-⁸⁷Sr DS to overcome the severe mass bias effects on the measured ⁸⁸Sr/⁸⁶Sr ratios, to improve the analytical accuracy of MC-ICP-MS δ^88/86Sr determination.