초록 |
The development and testing of a prototype portable gas chromatograph that combines a multiadsorbent preconcentrator for the analysis of volatile organic components in large-volume air samples are described. Vapor sample is injected through the wall-coated capillary column and detected by a flame ionization detector (FID). The fused silica column is wrapped with heater wire and sensor wire so that heating is provided directly at the column. In order to achieve detection limits in the ppb range, an online multibed preconcentrator containing beds of graphitized carbons and carbon molecular sieves is used. After sample collection, the flow direction through the preconcentrator is reversed, and the sample is thermally desorbed directly into the column. |