Practical sample pretreatment techniques coupled with capillary electrophoresis for real samples in complex matrices

By coupling a sample pretreatment technique of sample clean up and enrichment power with capillary electrophoresis (CE) of high-performance separation, the task of analyzing trace analytes in a complex matrix such as a biological sample can be carried out successfully with ease. This review aims for providing an overview of strategies to couple sample pretreatment techniques with capillary and related microscale (e.g., microchip) electrophoresis, practically adoptable in an automatic manner, without requiring serious modification of existing instruments to install sophisticated interfaces. In-line sample pretreatment techniques based on liquid phase microextraction performed before sample injection and on-line sample preconcentration techniques performed during or after sample injection are discussed with emphasis on the applicability to samples of high conductivity, commonly encountered for biological samples. An overview of the recent developments in microfluidic immobilized enzymatic microreactors which fit excellently to microchip CE is also given. (C) 2019 Elsevier B.V. All rights reserved.