PMID- 20556268
OWN - NLM
STAT- MEDLINE
DCOM- 20100820
LR  - 20100617
IS  - 1473-0197 (Print)
IS  - 1473-0189 (Linking)
VI  - 10
IP  - 13
DP  - 2010 Jul 7
TI  - Microfabricated thermal modulator for comprehensive two-dimensional micro gas 
      chromatography: design, thermal modeling, and preliminary testing.
PG  - 1647-54
LID - 10.1039/c001390k [doi]
AB  - In comprehensive two-dimensional gas chromatography (GC x GC), a modulator is 
      placed at the juncture between two separation columns to focus and re-inject 
      eluting mixture components, thereby enhancing the resolution and the selectivity 
      of analytes. As part of an effort to develop a microGC x microGC prototype, in 
      this report we present the design, fabrication, thermal operation, and initial 
      testing of a two-stage microscale thermal modulator (microTM). The microTM 
      contains two sequential serpentine Pyrex-on-Si microchannels (stages) that 
      cryogenically trap analytes eluting from the first-dimension column and thermally 
      inject them into the second-dimension column in a rapid, programmable manner. For 
      each modulation cycle (typically 5 s for cooling with refrigeration work of 200 J 
      and 100 ms for heating at 10 W), the microTM is kept approximately at -50 degrees 
      C by a solid-state thermoelectric cooling unit placed within a few tens of 
      micrometres of the device, and heated to 250 degrees C at 2800 degrees C s(-1) by 
      integrated resistive microheaters and then cooled back to -50 degrees C at 250 
      degrees C s(-1). Thermal crosstalk between the two stages is less than 9%. A 
      lumped heat transfer model is used to analyze the device design with respect to 
      the rates of heating and cooling, power dissipation, and inter-stage thermal 
      crosstalk as a function of Pyrex-membrane thickness, air-gap depth, and stage 
      separation distance. Experimental results are in agreement with trends predicted 
      by the model. Preliminary tests using a conventional capillary column interfaced 
      to the microTM demonstrate the capability for enhanced sensitivity and resolution 
      as well as the modulation of a mixture of alkanes.
FAU - Kim, Sung-Jin
AU  - Kim SJ
AD  - The Engineering Research Center for Wireless Integrated Microsystems (WIMS), 
      University of Michigan, Ann Arbor, MI 48109, USA.
FAU - Reidy, Shaelah M
AU  - Reidy SM
FAU - Block, Bruce P
AU  - Block BP
FAU - Wise, Kensall D
AU  - Wise KD
FAU - Zellers, Edward T
AU  - Zellers ET
FAU - Kurabayashi, Katsuo
AU  - Kurabayashi K
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20100324
PL  - England
TA  - Lab Chip
JT  - Lab on a chip
JID - 101128948
SB  - IM
MH  - Chromatography, Gas/*instrumentation
MH  - Computer Simulation
MH  - Computer-Aided Design
MH  - Equipment Design
MH  - Equipment Failure Analysis
MH  - Heating/*instrumentation
MH  - Microfluidic Analytical Techniques/*instrumentation
MH  - Miniaturization
MH  - Models, Theoretical
EDAT- 2010/06/18 06:00
MHDA- 2010/08/21 06:00
CRDT- 2010/06/18 06:00
PHST- 2010/06/18 06:00 [entrez]
PHST- 2010/06/18 06:00 [pubmed]
PHST- 2010/08/21 06:00 [medline]
AID - 10.1039/c001390k [doi]
PST - ppublish
SO  - Lab Chip. 2010 Jul 7;10(13):1647-54. doi: 10.1039/c001390k. Epub 2010 Mar 24.