Low-power concentration and separation using temperature gradient focusing via Joule heating.
We present an experimental study of temperature gradient focusing (TGF) exploiting an inherent Joule heating phenomenon. A simple variable-width PDMS device delivers rapid and repeatable focusing of model analytes using significantly lower power than conventional TGF techniques. High electric potential applied to the device induces a temperature gradient within the microchannel due to the channel's variable width, and the temperature-dependent mobility of the analytes causes focusing at a specific location. The PDMS device also shows simultaneous separation and concentration capability of a mixture of two sample analytes in less than 10 min. An experiment combining Joule heating with external heating/cooling further supports the hypothesis that temperature is indeed the dominant factor in achieving focusing with this technique.
Kim
Sun Min
SM
Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125, USA. sunmk@umich.edu
Sommer
Greg J
GJ
Burns
Mark A
MA
Hasselbrink
Ernest F
EF
D019793:Fluorescein / Q000032:analysis / Q000737:chemistry; D013696:Temperature
D019793:Fluorescein