Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

Infrared (IR) spectroscopy is used more and more to quantify different substances. Quantitative analysis puts some particular challenges when working with gas samples such as being sure of a calibration, the value of pressure and temperature, the amount of analyte with good precision. While working with different gases, we have observed that ammonia, NH3(g), showed a variable signal with time. Some others observed the same phenomenon. Ammonia presents a particular challenge for quantification with a decreasing signal. We consider this phenomenon as adsorption on the inside walls of the cell; this is not surprising when one considers the polarity of the molecule and the literature based on this behaviour for this gas. A series of experiments were made and quantitative results compared very well with calculations from validated data from the public database HITRAN.