Femtosecond laser ablation of multi-receiver inductively coupled plasma mass spectrometry was used to determine titanium isotopes in rutile

The Earth Science research team has developed a high-resolution method for the determination of titanium isotopes in rutile using femtosecond laser ablation multi-receiver inductively coupled Plasma mass spectrometry (fs-LA-MC-ICP-MS) to provide valuable insights into geological processes.

The researchers developed a new method to determine titanium isotopes in rutile with high precision and spatial resolution. The study is published in Part B of Spectrochimica Acta: In atomic spectroscopy, the femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs-LA-MC-ICP-MS) is used to analyze rutile, a common form of titanium dioxide (TiO 2) belonging to the oxide mineral group, and to study isotopic fractionation of titanium (1).

fs-LA-MC-ICP-MS is an advanced analytical technique involving the use of femtosecond lasers to ablate rutile samples with high precision and spatial resolution. The ablated material is then transported to an inductively coupled plasma (ICP) source, where it is ionized and introduced into a mass spectrometer. The multi-collector system in the mass spectrometer allows simultaneous measurement of multiple isotopes of titanium, providing valuable information about isotopic fractionation. The technique allows researchers to study the composition and isotope ratios of titanium in rutile samples, contributing to understanding geological processes and serving as potential geochemical tracers.

The crystallization of Fe-Ti oxides leads to significant changes of titanium isotopes during magmatic differentiation. Rutile (TiO 2) provides valuable insights into geological processes as a significant titanium-rich mineral in igneous, metamorphic and sedimentary rocks. The newly developed method using fs-LA-MC-ICP-MS enables researchers to determine mass dependent isotope fractionation of titanium in rutile with excellent accuracy and spatial resolution.

In order to improve the sensitivity of titanium signals and achieve low frequency ablation and high resolution analysis, a high sensitivity cone combination is used. However, the researchers encountered signal fluctuations that normally occur at low ablation frequencies. To solve this problem, a signal smoothing device was employed to ensure stable and accurate measurements.

The results show that the adjustment of laser parameters and the use of wet plasma conditions effectively reduce the deviation of higher δ 49 Ti values. Through these optimizations, the proposed method achieves spatial resolution of about 10 μm horizontally and 4 μm vertically. The accuracy of δ49Ti results is maintained at ±0.010%. Long-term measurements of rutile samples show excellent reproducibility, which verifies the reliability of the method.

A comparison of the measured values of nine natural rutile crystals using solutions MC-ICP-MS and fs-LA-MC-ICP-MS results in a consistent δ49 Ti value, further confirming the robustness of the newly developed technique. Notably, significant changes in δ49 Ti (up to ≈0.294%) were observed in 12 rutile samples, highlighting the potential of titanium isotopes in rutile as valuable geochemical tracers.

This pioneering method provides unprecedented insight into titanium isotopes in rutile crystals, allowing for a better understanding of geological processes and their effects. The identified homogeneous rutile crystals of USA75, Bra12, Sco2 and Bra6 can be used as important reference materials for in situ measurement of titanium isotope ratios in the future.

The study established a powerful analytical method for studying titanium isotopes in rutile, opening up new avenues for geochemical research and advancing our understanding of Earth's geological history.

Source: Laser Net