Hydrodynamic injection on electrophoresis microchips using an electronic micropipette.

Autor: Gabriel EF; Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil., Dos Santos RA; Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil., Lobo-Júnior EO; Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil., Rezende KC; Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil., Coltro WK; Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil; Instituto Nacional de Ciência e Tecnologia em Bioanalítica (INCTBio), 13083-970 Campinas, SP, Brazil. Electronic address: wendell@ufg.br.
Jazyk: angličtina
Zdroj: Talanta [Talanta] 2017 Jan 01; Vol. 162, pp. 19-23. Date of Electronic Publication: 2016 Sep 20.
DOI: 10.1016/j.talanta.2016.09.046
Abstrakt: Here we report for the first time the use of an electronic micropipette as hydrodynamic (HD) injector for microchip electrophoresis (ME) devices. The micropipette was directly coupled to a PDMS device, which had been fabricated in a simple cross format with two auxiliary channels for sample volume splitting. Sample flow during the injection procedure was controlled in automatic dispenser mode using a volume of 0.6µL. Channel width and device configuration were optimized and the best results were achieved using a simple cross layout containing two auxiliary channels with 300µm width for sample splitting. The performance of the HD injector was evaluated using a model mixture of high-mobility cationic species. The results obtained were compared to the data obtained via electrokinetic (EK) injection. Overall, the HD provided better analytical performance in terms of resolution and injection-to-injection repeatability. The relative standard deviation (RSD) values for peak intensities were lower than 5% (n=10) when the micropipette was employed. In comparison with EK injection, the use of the proposed HD injector revealed an unbiased profile for a mixture containing K + and Li + (300 µmol L -1 each) over various buffer concentrations. For EK injection, the peak areas decreased from 2.92 ± 0.20-0.72 ± 0.14Vs for K + and from 1.30 ± 0.10-0.38 ± 0.10Vs for Li + when the running buffer increased from 20 to 50mmolL -1 . For HD injection, the peak areas for K + and Li + exhibited average values of 2.48±0.07 and 2.10±0.06Vs, respectively. The limits of detection (LDs) for K + , Na + and Li + ranged from 18 to 23µmolL -1 . HD injection through an electronic micropipette allows to automatically dispense a bias-free amount of sample inside microchannels with acceptable repeatability. The proposed approach also exhibited instrumental simplicity, portability and minimal microfabrication requirements.
(Copyright © 2016 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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