Use of floating electrodes in transient isotachophoresis to increase the sensitivity of detection.
We report a protocol for on-chip electrophoretic sample loading and sample component separation in which each operation requires simultaneous control of the potential of only two electrodes: during the sample-loading phase, the potentials at the ends of the separation channel are electrically floating; during electrophoresis of the sample mixture down the separation channel, the potentials at the ends of the sample-introduction channel are floating. This method, which we call "floating-stacking," avoids the dispersion/distortion of the sample plug that is commonly associated with simultaneous electrical control of only two electrodes in a crossed-channel or offset-double-tee injection system. Further, when this floating loading/separation is done in the presence of back-transient-isotachophoresis, sample loss from the plug of material being injected is minimal and a significant concentration increase--up to 13x--of the sample components in the separated bands occurs relative to the commonly used "pinch-and-pull-back" technique (which requires simultaneous electrical control of four electrodes).
Kurnik
Ronald T
RT
ACLARA BioSciences, Inc, 1288 Pear Avenue, Mountain View, CA 94043, USA.
Boone
Travis D
TD
Nguyen
Uyen
U
Ricco
Antonio J
AJ
Williams
Steven J
SJ
D000081247:CSK Tyrosine-Protein Kinase; D003198:Computer Simulation; D004058:Diffusion; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods*; D019793:Fluorescein / Q000032:analysis; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D012680:Sensitivity and Specificity; D019061:src-Family Kinases
D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; D019793:Fluorescein