Automated membrane-based sampling and sample preparation exploiting flow-injection analysis

In this article, the state-of-the-art of flowing stream systems comprising membrane separation is reviewed. Special emphasis is given to the role of membranes as active barriers for enhanced selectivity and sensitivity of analytical procedures. The feasibility of performing separation processes in an on-line fashion (namely, dialysis, microdialysis, Donnan dialysis, gas diffusion, pervaporation, membrane extraction, and gas permeation via diffusion scrubbers) for sampling and sample clean-up is thoroughly presented, together with the benefits arising from the exploitation of flow injection systems. Attention is also given to the categorization of existing membranes and the wealth of flow-through configurations designed, along with relevant applications in the environmental field classified according to the aggregate state of the sample medium. (C) 2004 Elsevier Ltd. All rights reserved.