A systematic study of the chromatographic performance of a moving belt interface for LC/MS was conducted. For this work a specially designed nebulizer was constructed for deposition of the effluent from the LC column onto the moving belt. The role of various parameters of the nebulizer (e.g., gas flow rate and temperature) on chromatographic performance, as measured by the second moment of the generated chromatographic profiles, was examined. The influence of belt speed on peak variance was also examined. On the basis of these studies, the LC separation with normal bore (4.6 mm i.d.) columns was obtained under high-performance conditions along with mass spectral analyses of complex mixtures of substances. Successful operation with mobile phases of high water content was also achieved. In addition, detection limits as low as 40 pg were measured in the EI mode with polynuclear aromatic hydrocarbons, with linear dynamic ranges of at least 4 orders of magnitude. These studies demonstrate the utility of the moving belt interface for on-line high-performance LC/MS. (Copyright (c) 1983 by the American Chemical Society.)