Methods and systems for chemical analysis. For instance, a device for chemical analysis of a sample includes a housing, an inlet, a pump, multiple membranes and at least one detector. The housing contains an interior chamber of the device. The inlet on the housing introduces the sample into the interior chamber. The pump is connected to the housing to form a partial vacuum in the interior chamber. The multiple membranes have different response times to different constituents of the sample. The multiple membranes include at least a first membrane and a second membrane. At least one of the first membrane and the second membrane comprises a tubular portion. The multiple membranes have different response times to different constituents of the sample. The detector is for detecting the different constituents of the sample after interaction with the multiple membranes. In addition, a method for chemical analysis of a sample. A first step includes introducing a sample to multiple membranes having different response times to different constituents of the sample. A second step includes separating the different constituents of the sample due to the different response times of the multiple membranes. A third step includes detecting the different constituents of the gas after separating with the multiple membranes.