Membranes are high-performance materials with application in separation techniques. Their versatility relies on their broad chemical composition and their different mechanical properties (including porosity, thickness, size, and shape). Playing with the synthetic conditions, scientists can fabricate ad hoc membranes to solve a specific problem. This chapter summarizes the impact of membranes and related materials in the analytical sample preparation context. After a profound revision of the different extraction workflows where membranes can be used, the main polymeric membranes and their applications are systematically presented. The second part of the chapter is focused on novel phases such as fabric phases and paper-based sorptive phases in microextraction. The discussion of the supports (fabric and paper) and the main routes for their modifications (including physical deposition and chemical immobilization of sorptive phases) are presented in detail to give a general picture of the potential of these materials in the coming years.
