Simulation of aerosol transport, evaporation and scattering in the Evaporative Light Scattering Detector: Part B

Abstract. This study presents a comprehensive model for simulating aerosol dynamics and signal response in the Evaporative Light Scattering Detector (ELSD), a widely used analytical technique in liquid and supercritical fluid chromatography. The model integrates zero-dimensional model including droplet atomisation, convection, impingement, evaporation, and finally light scattering of the droplet cloud. The physically-based model includes chemical species properties, operational settings, and environmental conditions. The model accounts for complex phenomena such as multi-component evaporation, particle impingement, and size-dependent light scattering. The use of computational fluid dynamic (CFD) simulations provides detailed insights into flow characteristics within the ELSD geometry, and allows estimation of the droplet losses by impingement. Model predictions are compared against experimental data for various analytes and solvents across a range of concentrations and temperatures. The model accurately captures experimentally measured trends for volatile and semi-volatile species, but discrepancies are observed for non-volatile analytes at higher temperatures. The present simulations are the very first framework for modeling ELSD operation, and the developed model provides the first tool for optimising detector performance and interpreting results in chromatographic applications.