Temperature System sensitivity is controlled by sample preconcentration time and detector temperature. Detector sensitivity is an exponential function of detector temperature as shown in Figure 12 and maximum sensitivity is achieved with a minimum detector temperature of 0oC. At very high water vapor concentrations in the sampled air the

sensitivity to very volatile organic compounds (VVOC), a valve temperature of 70oC and an inlet temperature of 50oC works well. Although the column can be operated isothermally, better chromatography is achieved with at least a 1oC/second temperature ramping of the column. Sample times longer than 5 seconds are

ineffective due to ethanol breakthrough in the tenax filled loop trap. Detector sensitivity is an exponential function of temperature and a minimum detector temperature setting of 0oC results in maximum sensitivity. A linear response is achieved from 0 to over 3000 ppmv of ethanol. Ambient

compounds are injected into the helium gas. The organic compounds pass through a capillary column with different velocities and thus individual chemicals exit the column at characteristic times. As they exit the column they are detected and quantified by a solid state de¬tector. An internal high-speed

70oC valve, and 50oC inlet. Each data point is the average of three triplicate measurements. The averaged data points and linear response factor (counts/ppm) for each case is shown as insets in the figure. Summary Detecting ethanol in air and water is fast and easy

optimize the trapping efficiency of the loop trap system temperatures are necessarily low. Maximum SAW sensitivity is achieved by using a crystal temperature of 10oC or 0oC. A valve temperature of 70oC and an inlet temperature of 50oC are recommended. Because the loop trap contains only 1

552 and concentration as 415 ppm The zNose® system response is linear over a wide range of vapor concentrations. This is clearly shown by the N-point responses obtained from a series of 1-liter tedlar bags injected with increasing amounts of ethanol as shown in Figure 11. Detector Sensitivity vs

and 10oC detector temperatures, 7-replicate measurements at 100 and 13-ppm ethanol concentrations yield MDLs of 14.1 and 5.2 ppm respectively as shown in Figure 13. . Detection of Ethanol in Water Headspace vapors from water standards (20 mL water in a 40 mL vial) were sampled directly