Experimental Investigation on Water Adsorption Using Laser Photoacoustic Spectroscopy and Numerical Simulations

In the present research we propose a model to assess the water vapors adsorption capacity of a SiO(2) trap in the breathing circuit, aiming to reduce the loading of interfering compounds in human breath samples. In this study we used photoacoustic spectroscopy to analyze the SiO(2) adsorption of interfering compounds from human breath and numerical simulations to study the flow of expired breath gas through porous media. As a result, the highest adsorption rate was achieved with a flow rate of 300 sccm, while the lowest rate was achieved with a flow rate of 600 sccm. In the procedure of H(2)O removal from the human breath air samples, we determined a quantity of 213 cm(3) SiO(2) pearls to be used for a 750 mL sampling bag, in order to keep the detection of ethylene free of H(2)O interference. The data from this study encourages the premise that the SiO(2) trap is efficient in the reduction of interfering compounds (like water vapors) from the human breath.