Faster and improved microchip electrophoresis using a capillary bundle

Abstract

Joule heating generated in CE microchips is known to affect temperature gradient, electrophoretic mobility, diffusion of analytes, and ultimately the efficiency and reproducibility of the separation. One way of reducing the effect of Joule heating is to decrease the cross-section area of microchannels. Currently, due to the limit of fabrication technique and detection apparatus, the typical dimensions of CE microchannels are in the range of 50-200 microm. In this paper, we propose a novel approach of performing microchip CE in a bundle of extremely narrow channels by using photonic crystal fiber (PCF) as separation column. The PCF was simply encapsulated in a poly(methyl methacrylate) (PMMA) microchannel right after a T-shaped injector. CE was simultaneously but independently carried out in 54 narrow capillaries, each capillary with diameter of 3.7 microm. The capillary bundle could sustain high electric field strength up to 1000 V/cm due to efficient heat dissipation, thus faster and enhanced separation was attained.

Recent advances in capillary electrophoresis instrumentation for the analysis of explosives

“…Nevertheless, the recent studies have demonstrated the possibility of using these microstructures as pioneering separation platform in commercial CE techniques for the analysis of complex samples. [41] 4. Portable CE Table 1 summarizes the most relevant works conducted on the advancements made in the portable CE equipment during the last years.…”

“…CE conditions described in Table 1. (Modified from [41] with permissions of Elsevier). (In colour on the web only).…”

Dispersion of protein bands in a horseshoe microchannel during IEF

“…In a traditional, large-scale separation, Joule heating effect cannot be neglected because high voltages induce nonuniform temperature in a separation channel [21,22]. However, in a microfluidic chip, Joule heating is not a major source of dispersion because of the large channel surface-tovolume ratio [23]. Dispersion due to extended double-layers can be very high in a nanofluidic application [20], but its contribution will be negligible in the case of a microfluidic channel (10-100 mm) [18].…”

The use of a multichannel capillary for electrophoretic separations of mixtures of clinically important substances with contactless conductivity and UV photometric detection

“…The effect of the geometry of the separation space on the detection sensitivity has not been studied. It follows from the electropherograms given in [4,5] that the sensitivity of the fluorescence detection is comparable in multichannel and singlechannel geometric arrangement.…”