Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips

Abstract

Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in-line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10,000- to 100,000-fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.

Enhanced pH‐mediated stacking of anions for CE incorporating a dynamic pH junction

“…Field amplification also increases mass loading since large volume samples can be preconcentrated on-capillary, thus enhancing sensitivity [8][9][10]. Sample preconcentration and stacking techniques have recently been reviewed by Breadmore [ 11 ].…”

Review on the development of truly portable andin-situcapillary electrophoresis systems

“…This is a combination of high-performance liquid chromatography and CE where EOF is used instead of a hydraulic pump to move the mobile phase through the capillary [38,39]. Strictly, capillary (electro)-chromatography (CEC) is not a variation on CE but a variation on chromatography since the separation of analytes is not based on differences in the electrophoretic mobility.…”

Effect of a Low-conductivity Zone on Field-amplified Sample Stacking in Microchip Micellar Electrokinetic Chromatography

“…Therefore, various online sample preconcentration techniques have been developed to improve the sensitivity of MCE. [6][7][8][9][10] One of the successful strategies is to combine other preconcentration devices with MCE on a single microchip, e.g., solid-phase extraction, 11 filtering using a nanopore or nanochannel, 12,13 and so on. 14,15 As a typical example, Kim et al reported that the preconcentration with a nanochannel could attain a million-fold improvement of the detectability, but it required a long analysis time of over 30 min.…”