Methods Development for Low-Level Ammonia and Methane Analysis Using FTIR

Abstract

Current methods of ambient air ammonia analysis can accomplish accurate and precise data but are inadequate at achieving detection limits below 10 ppbv. The Fouriertransform infrared spectroscopy (FT-IR) technique has not yet been reported as an analytical method for measuring ammonia in conjunction with a passive sampling device, even though it theoretically can be very precise while maintaining accuracy. The purpose of this project is to determine the viability of this technique in quantifying ammonia levels for different applications such as monitoring air quality around chicken farms. Results from this project demonstrate the feasibility of low-level ammonia analysis by the FT-IR technique. A modified set-up is required due to the memory effects of ammonia. Originally a 10 m cell was used, which was changed out with a 10 cm cell with replaceable windows. Different window materials were tested to find out what interfered the least with ammonia. A 10 cm cell with a KBr plate window shows the most promising results showing low detection limits for measuring ammonia released from indirect sampling of ammonia on sulfuric acid-treated glass wool. Real-world data from samples collected at chicken coops suggest inconclusive results.