Premium
Single potential electrophoresis microchip with reduced bias using pressure pulse injection
Author(s) -
Lacharme Frédéric,
Gijs Martin A. M.
Publication year - 2006
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500723
Subject(s) - electrokinetic phenomena , analytical chemistry (journal) , electrophoresis , rhodamine b , chromatography , chemistry , microfluidics , capillary electrophoresis , spark plug , dilution , materials science , nanotechnology , biochemistry , photocatalysis , aerospace engineering , engineering , catalysis , physics , thermodynamics
We propose two variants of a new injection technique for use in electrophoresis microchips, called “front gate pressure injection” and “back gate pressure injection”, that both enable a controlled and reproducible sample introduction with reduced bias compared to electrokinetic gated injection. A continuous flow of a test solution of fluorescein/rhodamine B in 20 mM Tris/boric acid buffer (pH 8.6) sample test solution is electrokinetically driven near to the entrance of the separation channel, using a single voltage (3 kV) that is constant in time. A sample plug is injected in the separation channel by a pressure pulse of the order of 0.1 s. The latter is generated using the mechanical deflection of a PDMS membrane that is loosely placed on a dedicated chip reservoir. The analysis of the peak area ratio of the separated compounds demonstrates a nearly constant sample composition when using pressure‐based injection. A small remaining injection bias for the shortest membrane deflection times can be attributed to a dilution effect of the charged compound due to the presence of an electrical field transverse to the sample flow boundary in the channel junction.