Quantum cascade laser photoacoustic detection of nitrous oxide released from soils for biofuel production

In order to investigate the generation of greenhouse gases in sugarcane ethanol production chain, a comparative study of N₂O emission in artificially fertilized soils and soils free from fertilizers was carried out. Photoacoustic spectroscopy using quantum cascade laser with an emission ranging from 7.71 to 7.88 µm and differential photoacoustic cell were applied to detect nitrous oxide (N₂O), an important greenhouse gas emitted from soils cultivated with sugar cane. Owing to calibrate the experimental setup, an initial N₂O concentration was diluted with pure nitrogen and detection limit of 50 ppbv was achieved. The proposed methodology was selective and sensitive enough to detect N₂O from no fertilized and artificially fertilized soils. The measured N₂O concentration ranged from ppmv to ppbv.