Standalone Optical Emission Spectroscopy for Trace Analysis of Synthetic Vitreous Fiber Solutes in Simulated Lung Fluids: Building a Platform for Sustainable Innovation

The persistence of inorganic synthetic vitreous fibers (SVFs) in the lung is a critical factor in fibrogenesis and carcinogenesis. Toxicological evaluation of SVFs traditionally focuses on the “3D’s” of fiber toxicology: dose, dimension, and durability (biopersistence). Regulatory standards currently rely on in vivo testing to assess biopersistence, but increasing emphasis on ethical, cost-effective, and scalable alternatives has accelerated interest in acellular in vitro dissolution models.
Accurate prediction of SVF dissolution in simulated lung fluids (SLFs) requires highly sensitive and matrix-resilient analytical techniques to support robust in vivo/in vitro correlation (IVIVC). SLFs present a significant analytical challenge due to their high saline and surfactant content and the trace-level concentrations of dissolved inorganic species. This work pioneers development and implementation of inductively coupled plasma optical emission spectroscopy (ICP-OES) for trace-level SVF solute detection in complex SLF matrices.
Through critical process and instrumental optimization, including dual side-on plasma viewing and tailored calibration parameters, this method achieved a transformative >1000x enhancement in sensitivity and a 50x improvement in analytical precision compared to prior approaches. The platform demonstrated ppb-level detection capabilities and was extended to multiple SLF and SVF compositions. These results establish a robust and versatile analytical foundation for SVF characterization and pave the way for future in vitro dissolution testing strategies in materials development.