A method has been developed that uses uranium hexafluoride as the internal standard to quantitatively determine trace impurities in the uranium hexafluoride using relative response factors. A computer program was written to control the mass spectrometer and determine the concentrations of target impurities present. Overlapping spectra are deconvoluted using the Gauss-Seidel iterative method. The composition of the sample is determined by comparing the peak height ratios of the target impurities to the internal standard. Measurement parameters are easily modified using the menu driven program. A flexible database allows the list of target impurities to be extended to accommodate any changes in analytical requirements. The method has been adapted for automatic on-line measurements. The technique was evaluated by analysing a number of carefully prepared standards. Nine target impurities were studied which ranged in concentration from parts per million to percentages. An overall precision of fifteen percent was obtained. / Dissertation (MSc)--University of Pretoria, 1993. / gm2013 / Chemistry / unrestricted