Hydrodynamic injection on electrophoresis microchips using an electronic micropipette

TALANTA

卷:162

Article

Gabriel, Ellen F. M.¹  dos Santos, Rodrigo A.¹  Lobo-Junior, Eulicio O.¹  Rezende, Kariolanda C. A.¹  Coltro, Wendell K. T.^1,2 

[1] Univ Fed Goias, Inst Quim, Campus Samambaia, BR-74690900 Goiania, Go, Brazil

[2] Inst Nacl Ciencia & Tecnol Bioanalit INCTBio, BR-13083970 Campinas, SP, Brazil

关键词: Automatic dispensing;    Bias-free sample injection;    Microfluidic transport;    Portable instrumentation;   

DOI  :  10.1016/j.talanta.2016.09.046

来源: Elsevier

【 摘 要 】

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 0.6 mu L. Channel width and device configuration were optimized and the best results were achieved using a simple cross layout containing two auxiliary channels with 300 mu m 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 mu mol L-1 each) over various buffer concentrations. For EK injection, the peak areas decreased from 2.92 +/- 0.20-0.72 +/- 0.14 V s for K+ and from 1.30 +/- 0.10-0.38 +/- 0.10 V s for Li+ when the running buffer increased from 20 to 50 mmol L-1. For HD injection, the peak areas for K+ and Li+ exhibited average values of 2.48 +/- 0.07 and 2.10 +/- 0.06 V s, respectively. The limits of detection (LDs) for K+, Na+ and Li+ ranged from 18 to 23 mu mol L-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.

【 授权许可】

Free