Electrophoretic injection bias in a microchip valving scheme.
The pinched injection strategy, implemented on microfabricated fluidic devices (microchips), was investigated for an electrophoretic injection bias. Both the sample loading and dispensing steps were found to contribute to the injection bias whereby neutral species were injected preferentially to anionic species. In the sample loading step, neutral species filled a larger volume in the cross intersection than anionic species. Similarly, in the dispensing step, a larger volume of neutral analyte was injected than anionic analyte. Up to a 27% difference in injected volumes was observed. Fluorescently labeled amino acids were used as model analytes.
Alarie
J P
JP
Oak Ridge National Laboratory, TN 37831-6142, USA.
Jacobson
S C
SC
Ramsey
J M
JM
D001224:Aspartic Acid / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005456:Fluorescent Dyes / Q000032:analysis; D005470:Fluorometry; D005998:Glycine / Q000032:analysis; D008239:Lysine / Q000032:analysis; D008832:Microchemistry / Q000295:instrumentation*; D008904:Miniaturization; D012212:Rheology; D012235:Rhodamines / Q000032:analysis; D012815:Signal Processing, Computer-Assisted; D013048:Specimen Handling / Q000295:instrumentation / Q000379:methods*
D005456:Fluorescent Dyes; D012235:Rhodamines; D001224:Aspartic Acid; C009434:tetramethylrhodamine isothiocyanate; D008239:Lysine; D005998:Glycine