[en] Mass spectrometry is the primary tool employed for isotopic analysis. To alleviate many of the problems encountered with magnetic instruments, the use of a quadrupole mass spectrometer is proposed. A total system for performing routine nitrogen isotopic analysis is presented in this thesis. The system allows for a high ratio of analyte gas to residual gas for analysis. Linearity of spectral sweep is improved so averaged spectra can be integrated to improve accuracy of ratio. Accuracy and precision of better than 0.2 percent have been obtained. The major differences between magnetic and dynamic mass spectrometers are discussed with regard to the practical significance of these differences. The theory of the quadrupole mass spectrometer is reviewed and discussed in relationship to the variations in design parameters, the physical effects encountered, and the trade-offs that are encountered in the final system design. The construction and operation of a quadrupole mass spectrometer and associated systems are described. The chemical systems required for analysis are presented and evaluated, in respect to methods of analysis. The results of analyses are presented to show the accuracy and precision obtainable with this system. Precision of the data is examined with respect to the number of mass spectra averaged, the number of points integrated, and the rate at which the data are acquired. Finally several suggestions are brought forth in which the quadrupole mass spectrometer may prove itself to be a valuable research tool. (U.S.)