Abstract
Counter-pressure was used to extend the duration of field-amplified sample injection in isotachophoresis (FASI-ITP) in order to improve the detection of bacterial cells. Using 0.51-μm negatively charged encapsulated fluorescent beads as a model, the counter-pressure, injection and separation voltages, and times were optimized. Using 6-min 8,963-Pa counter-pressure FASI-ITP injections at −12 kV followed by mobilization of the ITP band with continued injection at −6 kV, the limit of detection (LOD) for Escherichia coli was improved to 78 cells/mL, a factor of 4 when compared with FASI-ITP without counter-pressure.
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Abbreviations
- CFU:
-
Colony-forming unit
- FASI:
-
Field-amplified sample injection
- LE:
-
Leading electrolyte
- TE:
-
Terminating electrolyte
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Acknowledgments
MCB acknowledges the ARC for a Future Fellowship (FT130100101). M.M. also acknowledges his ARC Future Fellowship Level 3 (FT120100559).
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Published in the topical collection Capillary Electrophoresis of Biomolecules with guest editor Lisa Holland
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Phung, S.C., Nai, Y.H., Macka, M. et al. Counter-pressure-assisted ITP with electrokinetic injection under field-amplified conditions for bacterial analysis. Anal Bioanal Chem 407, 6995–7002 (2015). https://doi.org/10.1007/s00216-015-8838-4
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DOI: https://doi.org/10.1007/s00216-015-8838-4