Contemporary sample stacking in analytical electrophoresis

Abstract

This contribution is a methodological review of the publications about the topic from the last 2 years. Therefore, it is primarily organized according to the methods and procedures used in surveyed papers and the origin and type of sample and specification of analytes form the secondary structure. The introductory part about navigation in the architecture of stacking brings a brief characterization of the various stacking methods, with the description of mutual links to each other and important differences among them. The main body of the article brings a survey of publications organized according to main principles of stacking and then according to the origin and type of the sample. Provided that the paper cited gave explicitly the relevant data, information about the BGE(s) used, procedure, detector employed, and reached LOD and/or concentration effect is given. The papers where the procedure used is a combination of diverse fragments and parts of various stacking techniques are mentioned in a special section on combined techniques. The concluding remarks in the final part of the review evaluate present state of art and the trends of sample stacking in CE.

Coupling of CE‐MS for protein and peptide analysis

“…It is necessary to mention also the problem with sensitivity in protein/peptide analysis by CE‐MS. The most frequently used methods for improved sensitivity are various online or offline concentration techniques such as SPE, liquid–liquid extraction, pH‐mediated stacking, field‐amplified stacking, and transient ITP (tITP) (for reviews see ). Really popular is using dynamic pH junction methods for stacking large volume injections of proteins .…”

Analysis of proteins and peptides by electromigration methods in microchips

“…Thus, the peptides and proteins of interest must be often extracted or preseparated and/or preconcentrated from the sample matrix before their analysis . Sample preconcentration methods are based on (i) electrophoretic principles (field‐amplified stacking, micellar‐based stacking, ITP, IEF, electropreconcentration) or (ii) on selective sorption/extraction (elution) methods (SPE , SPME , LLE ). Frequently, combination of both types of preconcentrations is employed.…”

Separation and stacking of iodine species from seafood using surfactant-coated multiwalled carbon nanotubes as a pseudo-stationary phase in capillary electrophoresis

“…In this method, sample is prepared in a lowconductivity matrix relative to the separation buffer, which this results in different electric field strength over the sample and background electrolyte. When sample ions pass through the boundary between the sample zone and the BGE, the migration of analytes becomes slower due to lower electric field strength, causing the sample analytes to be concentrated into a short zone during the stacking process [17]. Therefore, sample stacking is a useful technique to improve the detection sensitivity.…”