In this thesis, the Low temperature plasma ionization source (LTPI) beside the Ion mobility spectrometry is introduced as a soft ionization source. However this ionization source has been used for Ion mobility spectrometry and Mass spectrometry yet, but low temperature plasma probe that made has two important differences in comparison to other introduced probes. First, use a new method for direct injection of liquid sample into the system which the sample evaporates and then traorted to the plasma, so less amount of sample need and all of the sample vaporization are ionized. On the other hand, due to the sample ionization increment, the sensitivity of device will increases too. Second, use a glass sheath for sample ionization region that prevent vaporized sample wasting and it reduces consumption of helium gas and decreases the costs of analysis. Also, the necessary steps should be performance to Low temperature plasma ionization source (LTPI) an Ion mobility spectrometry together to avoid interference between field and electrical interactions. In this thesis, with the qualitative analysis of four samples of papaverine, caffeine, codeine, and diethylamin, the reduced mobility values and the compatibility with previous standard values is studied, and also by direct injection of two samples papverine and caffeine consider as experimental compositio and figure of merit obtained, the efficiency of LTPI-IMS device that made in this thesis, the quantitative measurement of chemical compounds was investigated that detection limit for each one got 0.3 mg/L and linear area for papaverine got 1-70mg/L and for caffeine obtained 0.9-50 mg/L.