The performance of a Hewlett Packard Particle Beam LC/MS interface is evaluated using EPA appendix VIII and IX compounds. The behavior of these priority pollutants in the interface could determine its feasibility as a future EPA certified technique. The evaluation process consists of studies to determine minimum detectable quantities (MDQ), linear response, and band broadening contributions. The MDQ's of the analytes in electron impact and chemical ionization modes are extrapolated from experimental signal to noise data. The linearity study involves ten compounds analyzed at five different concentrations. The response factors (RF) are calculated and discussed. The study concerning the band broadening contributions of the interface involves four independent variables (helium flow, desolvation chamber temperature, source temperature, and 96 methanol) and their effects on peak width. A Box–Behnken experimental design is used and described. Response surfaces are generated from the best fit equation describing the data. / Master of Science