Progress in on-line, at-line, and in-line coupling of sample treatment with capillary and microchip electrophoresis over the past 10 years: A review

The review presents an evaluation of the development of on-line, at-line and in-line sample treatment coupled with capillary and microchip electrophoresis over the last 10 years. In the first part, it describes different types of flow-gating interfaces (FGI) such as cross-FGI, coaxial-FGI, sheet-flow-FGI, and air-assisted-FGI and their fabrication using molding into polydimethylsiloxane and commercially available fittings. The second part deals with the coupling of capillary and microchip electrophoresis with microdialysis, solid-phase, liquid-phase, and membrane based extraction techniques. It mainly focuses on modern techniques such as extraction across supported liquid membrane, electroextraction, single drop microextraction, head space microextraction, and microdialysis with high spatial and temporal resolution. Finally, the design of sequential electrophoretic analysers and fabrication of SPE microcartridges with monolithic and molecularly imprinted polymeric sorbents are discussed. Applications include the monitoring of metabolites, neurotransmitters, peptides and proteins in body fluids and tissues to study processes in living organisms, as well as the monitoring of nutrients, minerals and waste compounds in food, natural and wastewater.

 

Comments:

The review provides an assessment of the advancements made in the field of sample treatment coupled with capillary and microchip electrophoresis over the past decade. It is divided into three parts, each focusing on different aspects of the technology.

The first part of the review discusses various types of flow-gating interfaces (FGI) that have been developed, namely cross-FGI, coaxial-FGI, sheet-flow-FGI, and air-assisted-FGI. These interfaces are used to control the flow of samples in electrophoresis systems. The review highlights the fabrication methods of these interfaces using polydimethylsiloxane (PDMS) molding and commercially available fittings.

The second part of the review focuses on the integration of capillary and microchip electrophoresis with different sample extraction techniques. These techniques include microdialysis, solid-phase extraction (SPE), liquid-phase extraction, and membrane-based extraction. The review emphasizes modern techniques such as extraction across supported liquid membrane, electroextraction, single drop microextraction, headspace microextraction, and microdialysis with high spatial and temporal resolution.

Lastly, the review discusses the design of sequential electrophoretic analyzers and the fabrication of SPE microcartridges with monolithic and molecularly imprinted polymeric sorbents. These advancements have enabled the monitoring of various substances in body fluids, tissues, food, natural water, and wastewater. Examples of the applications include the analysis of metabolites, neurotransmitters, peptides, proteins, nutrients, minerals, and waste compounds.

Overall, the review provides an overview of the developments in sample treatment techniques coupled with capillary and microchip electrophoresis. It highlights the advancements in flow-gating interfaces, sample extraction methods, and sequential analyzers, and their applications in studying living organisms and monitoring various substances in different samples.