Ion mobility spectrometry (IMS) is one of the most sensitive instrumental analysis technique, and is used extensively for drug and explosive materials detecting . In addition this method is applicable in laboratory for qualitative and quantitative analysis of chemical materials. In order to take spectrum of a sample by this technique, gas phase of sample should inter to the device. There are several methods for introducing the sample to the ion mobility spectrometry instrument. In this dissertation first of all, ion mobility Spectrometry sampling and it’s importance is introduced. Then several methods of inserting sample in IMS device have been described. After that, current sample inserting method in the Isfahan University of Technology Physical Chemistry Laboratory has been explained and its advantages and drawbacks have been discussed. Finally, a new method, delay method, for inserting of IMS sample will be proposed and the results are going to be discussed. In delay method the sample inserting technique carrier has been changed. In this method carrier gas is not continuously opened and before sample injection into the chamber is closed and it will be opened after a certain amount of time. This delay makes an opportunity for sample to evaporate. After full evaporation, it enters the apparatus by maximum concentration. Results show that using this method reduces time dispersion, increase sample concentration in time and intensify signal. As a result the sensitivity is increased and the diagnosis limit is decreased considerably. This method for direct injection of the sample solution eliminates the effect of solvent and injection speed. Also, by adjusting retention time of injection and chamber temperature, we can increase fragmentation of sample. Bond breaking of molecules makes it possible for us to detect and separate molecules that their spectrum are overlapped in their parent molecule. Furthermore by increasing temperature and residence time, heavy molecules which does not have signal in IMS before, could be thermally decomposed and their components could be detected.
