Green microextraction methodologies for sample preparations

Abstract

Microextraction for analytical sample preparations became a reality with the introduction of solid phase microextraction (SPME) in 1987–90, followed by the development over the next two decades of the liquid phase microextraction (LPME) modes: single drop microextraction (SDME), hollow-fiber microextraction (HF-LPME), electromembrane extraction (EME) and dispersive liquid-liquid microextraction (DLLME). Parallel to the developments of SPME and LPME, more sensitive instrumentation and environmentally friendly solvents were also being developed, requiring reduced sample amounts and solvent volumes. Automation, using standard instrumental autosamplers, fluid techniques and 96 well plate systems, has further enhanced microextraction methods. Over the last decade, a further reduction in sample size and extraction volume, along with automation, has been possible with the development of microfluidic systems. A crucial companion to this progress has been the introduction of tools for assessing the relative overall greenness of analytical microextraction methods, which should be used in comparing proposed methods with published procedures. In this review we provide the reader with categorized lists of microextraction reviews and application papers, which contain hundreds of additional references, as an aid to accessing needed information for use in further developments of these important analytical techniques.