New analytical technologies for measuring trace atmospheric pollutants are being introduced every year in the search for easier pollutant quantification. One example—already applied in some European countries—is the Micro-Chamber/Thermal Extractor™ – M-CTE250I aka “Micro-chamber”, a compact emission-analysis system whose main advantages are the small sample volume required, the low carrier-gas flow rate and rapid results. However, these emerging technologies still lack thorough validation and standardized operating protocols. The present study proposes the use of Computational Fluid Dynamics (CFD) simulations to characterise internal flow and mass-transfer mechanism, to quantify local and global mass-transfer coefficients of hydrogen sulphide (H₂S) inside the device. A three-dimensional model of a single stainless-steel slot (57 mm diameter, 14 mm height, 15 mL liquid) was built in ANSYS Fluent. The carrier gas (N₂, 50 mL min⁻¹) yields a Reynolds number of 22.8, therefore the flow is solved as laminar incompressible. Model outputs will be validated against independent decay experiments conducted at 21, 25 and 30 °C. The resulting CFD framework will support future calibration of micro-chambers, guide protocol development, and improve emission-factor estimates for quiescent wastewater sources.
