求译 句中两个trap

求译 句中两个trap
Similarly,the effect of adding a carbon dioxide 【trap】 between the sample bag and the instrument was assessed with the 23-component gas standard.Initial attempts to speciate the light hydrocarbons in exhaust from natural gas vehicles (NGV's) revealed a problem with the rapid GC method.Excessive amounts of carbon dioxide and water vapor were deposited onto the Alumnia PLOT column and seriously degraded the performance of the column.To alleviate the problem a chemical 【trap】 was installed on the inlet to the rapid GC.