The basic principles for the preparation of SPME fibers with satisfying selectivity, sensitivity, loading capacities and stabilities are summarized here in terms of the physicochemical properties of the coating materials and the supporting substrates of SPME fibers. While the main part of this chapter focuses on the advances in developing the most widely used coating materials, including ionic liquids, polymeric ionic liquids, carbonaceous materials, molecularly imprinted polymers, metal-organic frameworks, metals and metal oxides, conductive polymers, modified silica, as well as their composites, into SPME fibers. Meanwhile, the applications of novel SPME fibers in analyzing diverse analytes in different sample matrices are briefly reviewed, including the emerging applications of SPME in the extraction of bioactive compounds in living animals and plants.Keywords SPME fiber coating Á Ionic liquid Á Polymeric ionic liquid Á Graphene Á Carbon nanotube Á Molecularly imprinted polymer Á Metal-organic framework Á Metal and metal oxide Á Conductive polymer Á Modified silica
IntroductionThe outstanding features of solid-phase microextraction (SPME), including rapid and simple operating procedures, slight disturbance to investigated systems, reduced consumption of solvents, and feasibility of automation, continuously inspire new explorations of SPME in various frontiers, such as metabolome detection [1], central nervous systems studies [2], pharmacokinetic studies [3], environmental analysis [4], and food analysis [5]. On the other hand, the diversity of the physicochemical properties of the target analytes and the complicity of the sample matrices require the development of new SPME devices to nourish the new