| 摘要 |
The invention relates to methods of increasing the relative concentration of a target molecule in a gas stream, so that it can be more easily detected by a semiconducting metal oxide based sensor. In a first step of one method, a gas stream is passed through an adsorbent. The gas stream contains molecules of the target molecule in a mixture containing molecules of at least one non-target molecule. Both the target and non-target molecules are adsorbed on the adsorbent. In a second step, another gas stream containing molecules of a chemical displacer is passed through the adsorbent. The molecules of the chemical displacer adsorb on the adsorbent to selectively displace the target molecules from the adsorbent while leaving the non-target molecules adsorbed. The chemical displacement causes the displaced target molecules to enter the gas stream. The gas stream can then be passed through a semiconducting metal oxide based sensor to detect the target molecules. Alternatively, the adsorbed chemical displacer displaces the non-target molecules while leaving the target molecules adsorbed on the adsorbent surface. In either case, a separation of the target and non-target molecules is achieved. In another method, an adsorbent is pretreated with a chemical displacer so that chemical displacer molecules are adsorbed on the adsorbent. A gas stream is passed through the adsorbent, the gas stream containing target molecules mixed non-target molecules. The target molecules adsorb on the adsorbent while the non-target molecules do not adsorb and instead remain in the gas stream. The chemical displacer molecules are selectively adsorbed relative to the non-target molecules to prevent their adsorption on the adsorbent. Alternatively, the chemical displacer can be selectively adsorbed relative to the target molecules, so that the non-target molecules adsorb on the adsorbent while the target molecules do not adsorb and remain in the gas stream.
|
