Abstract: A flow manifold for high purity analyzers is described, in which all flow control valving is positioned downstream of the measurement device. Specifically, this new flow manifold is applied to a high purity moisture analyzer that utilizes a quartz crystal microbalance detector. The proposed flow design eliminates outgassing and contamination from upstream valving, deadlegs in the flow path, and significantly improves instrument response speed. Experimental data is provided to confirm the performance advantage of the new manifold design over existing designs.