Ppm Of Vapour Research Articles

Thermoluminescence caused by adsorbates (adsorption thermoluminescence) appears in the process of heating Al 2O 3 powder that had previously adsorbed the vapour of an organic solvent, such as ethanol or acetone, at room temperature. The profiles of the thermoluminescence spectrum and glow curve depend on the kind of adsorbed vapour. The total amount of emitted light L depends on the concentration of the vapour in air, and L increases with an increase in the duration of adsorption. The adsorbates that act as the origin of the thermoluminescence are accumulated through a Langmuir-type adsorption process of very low activation energy (about 0.02 eV). These characteristics of the adsorption thermoluminescence enable us to discriminate and determine very low concentrations of these vapours. For example, L is proportional to the concentration of acetone vapour below 20 ppm for an adsorption time of 10 min, and the 1 ppm of vapour can be measured with good reproducibility.

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