The 2, 4, 6- trinitrotoluene (TNT) vapor detection by quartz crystal microbalance (QCM) coated with 18-crown-6 ether film is introduced. The film acts as selective or sensitive layer for detecting TNT molecule. The frequency shift response is depend on the amount of mass of molecule adhere on the coated film surface. In this study, the concentrations of TNT vapor which is related to responses are studied. It shows that the TNT vapor concentration is related to the time for steady state condition and the frequency shift response. The high concentration vapor will increase the frequency shift response but increase the steady state time.
