On-line measurement of electroosmosis in capillary electrophoresis using a conductivity cell

Wanders, BJ Bart; Goor, van de Aaam; Everaerts, FM Frans

doi:10.1016/0021-9673(93)80671-t

Cited by 28 publications

(23 citation statements)

References 13 publications

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“…Apparently u E linearly increases with voltage, indicating that the mobility was constant. The measurement is also extrapolated to the lowest u E 5 0.021 mm s 21 and it fits very closely to the linear relation between u E and voltage, probably because of the nearly linear relationship between flow velocity and fluorescence intensity at low velocity range. The error bar is also shown in Fig.…”

Section: Measurement Of Eofmentioning

confidence: 57%

“…Here only one stream of dye solution was used, so that the dye concentration is constant at the detection position. In the initial stage, the flow rate Q was set at 1 ml min 21 . After a period of time, the flow and dye concentration in the channel became steady.…”

Section: Signal Transductionmentioning

confidence: 99%

“…In Fig. 3, the signal was recorded for 15 s with the flow rate Q 1 5 1 ml min 21 . During this period, the fluorescence intensity (arbitrary units) was nearly constant at 107.5.…”

Section: Signal Transductionmentioning

confidence: 99%

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Laser induced fluorescence photobleaching anemometer for microfluidic devices

Wang

2005

Lab Chip

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We have developed a novel, non-intrusive fluid velocity measurement method based on photobleaching of a fluorescent dye for microfluidic devices. The residence time of the fluorescent dye in a laser beam depends on the flow velocity and approximately corresponds to the decaying time of the photobleaching of the dye in the laser beam. The residence time is inversely proportional to the flow velocity. The fluorescence intensity increases with the flow velocity due to the decrease of the residence time. A calibration curve between fluorescence intensity and known flow velocity should be obtained first. The calibration relationship is then used to calculate the flow velocity directly from the measured fluorescence intensity signal. The new method can measure the velocity very quickly and is easy to use. It is demonstrated for both pressure driven flow and electroosmotic flow.

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Section: Measurement Of Eofmentioning

confidence: 57%

Section: Signal Transductionmentioning

confidence: 99%

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Laser induced fluorescence photobleaching anemometer for microfluidic devices

Wang

2005

Lab Chip

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“…If the sensing electrode is placed too close to the capillary, interferences with the separation field will occur, but if the electrode is placed too far away from the capillary outlet, peak-broadening will be introduced and the detection sensitivity will decrease. Since few details on the detector technology were provided for the work described above and also for the measurements of the electroosmotic flow in CE [30] and the determination of chlorophenoxy acid herbicides by CE using integrated potential gradient detection [31], this work is excluded from Table 1.…”

Section: Contact Conductivity Detection In Capillariesmentioning

confidence: 99%

Conductivity detection for conventional and miniaturised capillary electrophoresis systems

Guijt¹,

Evenhuis²,

Macka³

et al. 2004

Electrophoresis

128

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Since the introduction of capillary electrophoresis (CE), conductivity detection has been an attractive means of detection. No additional chemical properties are required for detection, and no loss in sensitivity is expected when miniaturising the detector to scale with narrow-bore capillaries or even to the microchip format. Integration of conductivity and CE, however, involves a challenging combination of engineering issues. In conductivity detection the resistance of the solution is most frequently measured in an alternating current (AC) circuit. The influence of capacitors both in series and in parallel with the solution resistance should be minimised during conductivity measurements. For contact conductivity measurements, the positioning and alignment of the detection electrodes is crucial. A contact conductivity detector for CE has been commercially available, but was withdrawn from the market. Microfabrication technology enables integration and precise alignment of electrodes, resulting in the popularity of conductivity detection in microfluidic devices. In contactless conductivity detection, the alignment of the electrodes with respect to the capillary is less crucial. Contactless conductivity detection (CCD) was introduced in capillary CE, and similar electronics have been applied for CCD using planar electrodes in microfluidic devices. A contactless conductivity detector for capillaries has been commercialised recently. In this review, different approaches towards conductivity detection in capillaries and chip-based CE are discussed. In contrast to previous reviews, the focus of the present review is on the technological developments and challenges in conductivity detection in CE.

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“…A determinação do fluxo eletroosmótico 98 e o estudo dos seus modificadores 99 , bem como a determinação da mobilidade de monoaminas 100 e a previsão do formato de picos 101 , têm sido conduzidas com o auxílio deste tipo de detecção.…”

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Detecção eletroquímica em eletroforese capilar

Silva¹

2003

Quím. Nova

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Recebido em 12/11/01; aceito em 11/6/02 ELECTROCHEMICAL DETECTION IN CAPILLARY ELECTROPHORESIS. This review focuses the development of electrochemical detection systems coupled to capillary electrophoresis. Conductometric, amperometric, voltametric, and potentiometric modes of detection are reviewed. The positioning of the electrodes, interferences of high electric field, and the materials employed in the fabrication and modification of the electrodes are discussed. The advantages of the use of electrochemical detection with capillary electrophoresis, regarding to the sensitivity and selectivity, is exemplified with a large number of applications. Also, the use of electrochemical detection systems in microchip technology is addressed.

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On-line measurement of electroosmosis in capillary electrophoresis using a conductivity cell

Cited by 28 publications

References 13 publications

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Conductivity detection for conventional and miniaturised capillary electrophoresis systems

Detecção eletroquímica em eletroforese capilar

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