Advances and applications of in-tube solid-phase microextraction for analysis of proteins

In-tube solid-phase microextraction (IT-SPME) with capillary column as extraction device is a well-established green extraction technique with a lot of applications in the fields of biomedicine, food and environment. This article reviews the research contributions of IT-SPME for analysis of proteins. The paper first briefly describes the history of IT-SPME. Then, the development and principle of IT-SPME for analysis of proteins are introduced, in which capillary column configurations of IT-SPME and instruments for quantitative analysis of proteins are summarized. Subsequently, the synthesis strategy and recognition principle of different recognition units, including antibodies, aptamers, molecularly imprinted polymers, and boronate affinity materials, are discussed in detail. This part also introduces several rare recognition units, including lectins, restricted access materials, lysine modified with β-cyclodextrin and cell membrane. The development trend and possible future direction of IT-SPME for analysis of proteins are mentioned.