A quantitative study of continuous flow‐counterbalanced capillary electrophoresis for sample purification

McLaren, David G.; Chen, David D. Y.

doi:10.1002/elps.200305453

Cited by 18 publications

(19 citation statements)

References 25 publications

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“…CE fraction collection methods have subsequently been developed for continuous fractionation with membranes [2,3], disposable microcentrifuge tubes [4], and capillaries [5]. Flow-counterbalanced capillary electrophoresis (FCCE) was later developed to increase the efficiency and resolving power of CE [6] and has been used to isolate an amino acid with a purity of >99.5% [7,8]. Mori et al applied the FCCE technique to the separation of metal ions with similar ionic radii [9].…”

Section: Introductionmentioning

confidence: 99%

Purification of anionic fluorescent probes through precise fraction collection with a two‐point detection system using multiple‐stacking preparative capillary transient isotachophoresis

et al. 2020

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A novel combination of CE-based separation techniques was used for the precise fractionation of ionic compounds from impurities. The combination of on-capillary concentration and separation using transient isotachophoresis, with multiple injections and a two-point detection system provided higher efficiency, and accuracy at a microliter-scale injection volume, than when CE was individually used for purification. In this paper, we present successful applications of the CE fractionation techniques for the purification of fluorescein, fluorescein-4-isothiocyanate, two fluorescent metal ion probes, and a fluorescein-modified DNA aptamer. The purity of the isolated fluorescent probes ranged from 95 to 99%. Such high purity could not be achieved using chromatographic purification techniques. With relatively low dilution factors of 6-9, the purified probe solutions were practical for use as purified stock solutions. In addition, the fluorescein-modified DNA aptamer purified by our method was successfully used in a thrombin binding assay. The method developed was useful for the purification of anionic fluorescent reagents to be of ultratrace analytical grade for use with CE-LIF.

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Section: Introductionmentioning

confidence: 99%

Purification of anionic fluorescent probes through precise fraction collection with a two‐point detection system using multiple‐stacking preparative capillary transient isotachophoresis

et al. 2020

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“…18 Moreover, researchers have exploited such steady but counteracting electrophoretic and EOF/pressure-driven ow modes on other occasions to either focus sample zones 19 or design continuous charge based separation methods. 20,21 Implementation of FCCE in precisely fabricated micro-and nanouidic conduits has the potential for substantially enhancing the resolving power of this separation method as well as integrating it to other analytical procedures on lab-on-achip devices. 22 The need for dynamically controlling the pressure-gradient in the FCCE column, however, presents a significant challenge in implementing this technique on the microchip platform.…”

Section: Introductionmentioning

confidence: 99%

Microfluidic flow counterbalanced capillary electrophoresis

Xia

Dutta

2013

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Flow counterbalanced capillary electrophoresis (FCCE) offers a powerful approach to realizing difficult charge based separations in compact microchip devices with application of relatively small electrical voltages. The need for dynamically controlling the pressure-gradient in the FCCE column however presents a significant challenge in implementing this technique on the microchip platform. In this article, we report the use of a simple on-chip pumping unit that allows precise introduction of a periodic pressure-driven backflow into a microfluidic separation channel enabling an FCCE analysis. The backflow in our device was produced by fabricating a shallow segment (0.5 μm deep) downstream of the analysis column (5 μm deep) and applying an electric field across it. A mismatch in the electroosmotic transport rate at the interface of this segment was shown to yield a pressure-gradient that could reverse the flow of the analyte bands without inverting the direction of the electric field. Although such a pressure-gradient also led to additional band broadening in the system, overall, the separation resolution of our device was observed to improve with an increasing number of back-and-forth sample passes through the analysis channel. For our current design, the corresponding improvement in the effective separation length was as much as 52% of the actual distance travelled by the chosen FITC-labeled amino acid samples. The reported device is well suited for further miniaturization of the FCCE method to the nanofluidic length scale which likely would improve its performance, and is easily integrable to other analytical procedures on the microchip platform for lab-on-a-chip applications.

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“…16 Counterbalance CE (CbCE) using reversed EOF is another method to resolve closely related compounds. The EOF is reversed either by pressure (ow counterbalanced CE, FCCE), [17][18][19] or by changing the polarity of the electrodes thereby increasing the residence time of the analyte in the capillary (Fig. S1 †).…”

Section: Introductionmentioning

confidence: 99%

An enhanced capillary electrophoresis method for characterizing natural organic matter

Cottrell

Cheng

Lam

et al. 2013

Analyst

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Natural organic matter (NOM) is ubiquitous and is one of the most complex naturally occurring mixtures. NOM plays an essential role in the global carbon cycle; atmospheric and natural water photochemistry; and the long-range transport of trace compounds and contaminants. There is a dearth of separation techniques capable of resolving this highly complex mixture. To our knowledge, this is the first reported use of ultrahigh resolution counterbalance capillary electrophoresis to resolve natural organic matter. The new separation strategy uses a low pH, high concentration phosphate buffer to reduce the capillary electroosmotic flow (EOF). Changing the polarity of the electrodes reverses the EOF to counterbalance the electrophoretic mobility. Sample stacking further improves the counterbalance separation. The combination of these conditions results in an electropherogram comprised up to three hundred peaks superimposed on the characteristic "humic hump" of NOM. Fraction collection, followed by three-dimensional emission excitation spectroscopy (EEMs) and UV spectroscopy generated a distinct profile of fluorescent and UV absorbing components. This enhanced counterbalance capillary electrophoresis method is a potentially powerful technique for the characterization and separation of NOM and complex environmental mixtures in general.

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A quantitative study of continuous flow‐counterbalanced capillary electrophoresis for sample purification

Cited by 18 publications

References 25 publications

Purification of anionic fluorescent probes through precise fraction collection with a two‐point detection system using multiple‐stacking preparative capillary transient isotachophoresis

Purification of anionic fluorescent probes through precise fraction collection with a two‐point detection system using multiple‐stacking preparative capillary transient isotachophoresis

Microfluidic flow counterbalanced capillary electrophoresis

An enhanced capillary electrophoresis method for characterizing natural organic matter

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