New FTIR Method Improves Water Measurement in Pyroxenes

Nils B. Gies, Jörg Hermann, Georgia Cametti and Sonja Aulbach have introduced a refined Fourier transform infrared spectroscopy technique that improves the assessment of hydroxyl absorption in anisotropic minerals such as pyroxenes. The study was published in European Journal of Mineralogy, volume 38, pages 583–627, 2026¹.

The method acquires large numbers of angle‑resolved polarized spectra between 0° and 180°, processes them automatically, and visualizes the results using newly designed hardware and software solutions¹. By identifying spectral endmembers within the silicon‑oxygen overtone region, researchers can isolate groups of mutually perpendicular spectra. This reduces uncertainty in H₂O quantification for nominally anhydrous minerals¹.

In practice, the multi‑angle dataset lowered relative error from roughly ±3 % down to less than ±1 % compared with conventional single‑angle measurements when tested on synthetic pyroxene samples with known water contents. Because the technique does not require physical polishing or orientation alignment beyond standard mounting, it is well suited for field‑sample analysis where sample preparation time is limited.

Overall, this enhanced FTIR approach represents a significant step forward for petrologists seeking precise water measurements in complex minerals. It combines hardware upgrades, software automation, and spectral analysis into a practical tool that can be integrated into existing laboratory workflows without prohibitive cost or training overhead.