Over the last few years, membranes have been used to develop new approaches in analytical extraction, concentration and cleanup. An important advantage of membrane processes is that the sample and the extraction phase can be continuously brought into contact without physical mixing, and may be directly interfaced to an analytical instrument. This provides the basis for automated, real-time monitoring. Membrane extraction has been applied to a wide range of organic and inorganic analytes, and has been directly interfaced with chromatography, spectroscopy and mass spectrometry. Implementations of membrane extraction are diverse, encompassing different types of membranes, module designs and configurations. This review highlights some of these, and particularly the unique capabilities in automated, and on-line measurements.