In this thesis the quantitative analysis of two peptide drugs, consisting of buserelin and calcitonin salmon carried out, using electrospray ion mobility spectrometry for first time. Ion mobility spectra were obtained for both drugs. In the spectrum related to buserlin and calcitonin salmon two and four peaks appeared, respectively. Reduced mobility values of 1.06 and 0.57 cm 2 V -1 s -1 for buserelin and 0.96, 0.80, 0.70 and 0.59 cm 2 V -1 s -1 for calcitonin salmon were obtained. For quantitative analysis, the presence of acetic acid and water on signal intensity of these two substances was studied and percent of water-acetic acid optimized value was obtained. At first, the quantitative analysis of buserelin in the mixture was done, that was as so: 1: 29: 70 (acetic acid: water: methanol). In each analysis, ion mobility spectra was recorded and integral of area below the peaks, when signal intensity was maximum, was registered as instrument response. In this case, linear range was 0.1-5 µg/mL and detection limit was 0.01 µg/mL. Relative standard deviation was 3.5%. Calcitonin Salmon too, was analysis similarly. Linear range and detection limit 0.4-10.0 µg/mL and 0.03 µg/mL were obtained, respectively. Relative standard deviation was 3.8%. In this thesis, the liquid- liquid electroextraction method was used for the sample preparation, which is independent of the peptide?s isoelectric point, hydrophilicity or hydrophilicity. In order to a cell (Glass tube with a diameter of 15 mm and length 108 mm and a conical end) designed and made. A rod electrode made of platinum with a diameter of 0.5 mm as the cathode was welded to the end of cell. A electrode with a flat circled end made of gold with a diameter of 15 mm as anode were used. The time of 15 minute and the potential of 5kV were chosen as optimum time and potential for extraction. For buserelin, calibration curve was obtained. Linear range was 0.2-2.0 µg/mL for buserelin. Detection limits was 0.03µg/mL for buserelin. Relative standard deviations of buserelin was 8.0% , the recovery percentage was for buserelin 40-43. Considering these represented results, it is expected that this peptide analysis method whit advantage such as simplicity, fast response, suitable detection limit be used for quantitative analysis of peptides in biologicale and pharmacology fields. Calcitonin almon needed to potential higher than 5kV for the extraction but it is not possible to apply potential higher than 5 kV in this cell.