lab-on-a-chip miniaturized on- line liquid chromatography...monitoring of esterification reaction by...
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Lab-on-a-chip miniaturized on-line liquid chromatography
Dr. Scott GilbertCrystal Vision Microsystems, LLCShoreline, Washington
CPAC Satellite Workshop, Rome, Italy, March 20-22,2006
©2006 Crystal Vision Microsystems LLC2
Lab-on-chip approach
Compactness – sensor-sized deviceSimplicity of operationReduction of moving parts – no (mechanical) pumpsRobustness Inexpensive and facile maintenance
©2006 Crystal Vision Microsystems LLC3
“Conventional” Process HPLC
Dionex DX-800Process Analyzer
©2006 Crystal Vision Microsystems LLC4
Concept of a Modular LC Process Analyzer based on Lab-on-Chip
NeSSI Generation III dream analyzer
©2006 Crystal Vision Microsystems LLC5
Examples of commercially available microfluidic LC
Agilent’s HPLC-Chip™
Nanostream’s Brio™ 24-column parallel LC polymer cartridge
Veloce® µ-parallel LC System
LC/MS system
©2006 Crystal Vision Microsystems LLC6
Design issues addressed
Process stream sampling “Gearing down”, or reduction of macroflow to microflow
Obtaining a representative sample
©2006 Crystal Vision Microsystems LLC7
Split flow approach to sampling
Liters per minute
microliters per minute
nanoliters per minute
©2006 Crystal Vision Microsystems LLC8
Chip Layout20
mmInlet lines
Detector electrodes
Column
©2006 Crystal Vision Microsystems LLC9
Capillary geometries for open channel liquid chromatography
d
“Ribbon” or rectangular microchannel
d
wConventional tubular capillary
Advantage – lower pressure drop with same diffusion path
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Chip mount and lab set-up
Air
©2006 Crystal Vision Microsystems LLC11
Plug generation by flow-injection
©2006 Crystal Vision Microsystems LLC12
Variable injection volumes
0.7
0.6
0.5
0.4
0.3
0.2
Current [nA]
120100806040200Time since injection [s]
1500 ms 1000 ms 500 ms 200 ms
©2006 Crystal Vision Microsystems LLC13
Chromatographic behavior
0.8
0.6
0.4
0.2
Current [nA]
120100806040200Time since injection [s]
5mM Phenol 5mM Pentylphenol 2.5mM Phenol & Pentylphenol
OH
©2006 Crystal Vision Microsystems LLC14
Resolution improvement by coated sol gel stationary phase
3
2
1
0
Current [nA]
140120100806040200Time since injection [s]
0.5
0.4
0.3
0.2
Current [nA]
Sol-Gel coating No coating
©2006 Crystal Vision Microsystems LLC15
Reproducibility of injections
Time (min)
Am
pero
met
ric re
spon
se (n
A)
0 4 8 12 16 20 24 28 32 360
5
10
15
20
25
30
35
Time (min)
Am
pero
met
ric re
spon
se (n
A)
32.8 32.9 33 33.1 33.2 33.3 33.4 33.5 33.65
10
15
20
25
30
35
10 ppm hydroquinone, phenol, trichlorophenol
90% methanol/H2O
©2006 Crystal Vision Microsystems LLC16
Continuous reaction monitoring configuration
Split flow
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Schiff base formation – aniline consumption
6
5
4
3
2
1
0
Am
pero
met
ric re
spon
se (n
A)
10501000950900850Time (sec)
85.0 95.090.0 100.0 105.0
Time (min)
Am
pero
met
ric re
spon
se (n
A)
0 8 16 24 32 40 48 56 64 720
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
©2006 Crystal Vision Microsystems LLC18
Monitoring of esterification reaction by chip-based liquidchromatography: Production of ethyl salicylate in ethanol under reflux - catalysed with nafion 117
9.6
9.8
10
10.2
10.4
10.6
10.8
0 50 100 150 200 250 300
time (sec)
Curr
ent (
nA)
ethyl salicylatesalicylic acid
30 minutes
9.6
9.8
10
10.2
10.4
10.6
10.8
0 50 100 150 200 250 300
time (sec)
Curr
ent (
nA) salicylic acid
10 minutes
chromatographic conditions: mobile phase: 10% MeOH-90%H2O / C8-coated channel. flow rate 50 nl/min – detection amperometric +1.0V vs Pt. Run times under 4 minutes
ethyl salicylate
0
100
200
300
400
500
600
0 20 40 60 80
time (min)
conc
entra
tion
(ppm
)
salicylic acid
ethyl salicylate
Rate data for reactionbased on LC devicemeasurements
©2006 Crystal Vision Microsystems LLC19
On-line sample conditioning
micromixer
waste
diluent
H-filter
Concentrated stream
return
Performs functions of :dilutionfiltrationpH conditioning
©2006 Crystal Vision Microsystems LLC20
Microreactor interfacing
Parallel LC analysis platform
©2006 Crystal Vision Microsystems LLC21
On-line Installation with CPC Microreactor at CPAC Laboratory, U. Washington
©2006 Crystal Vision Microsystems LLC22
Advantages of this technology
Integrated channels on “monolithic” substrate to replace conventional tubingAnalyte sampling driven by line pressureMicrochannels appropriate for “open tubular” LCLow pressure operation – no need for a HPLC pump
©2006 Crystal Vision Microsystems LLC23
Summary and Perspectives
Continuous flow-through monitoring of chemicalreactionsMeasurements under 4 minutesOperation pressures of under 1 bar
Future work includes:Wall-coated polymer stationary phase for higherresolution separationsOptimizing sample conditioning cartridgesBuilding a modular analyzer prototype for testinglarger volume reactors
©2006 Crystal Vision Microsystems LLC24
Thanks for your attention!
Lake Washington
University of Washington, Seattle campus
Swiss Federal Institute of Technology, Lausanne(where we started…)
Lake Geneva
©2006 Crystal Vision Microsystems LLC25
Q&A Hyperlinks
Dionex process LC
Split flow approach
Variable injection
Schiff base data
Advantages
Concept of module
Split flow approach
Chromatographic behavior
Esterification reaction
Summary & Perspectives
Lab on Chip approach
Chip layout Resolution improvement
Sample conditioning
Open tubular and capillaries
Commercial chip LC
Mount and setup
Serial injections
Microreactor interfacing
Design equations
Design Issues
Injection images
Continuous batch monitor
CPC micoreactor
Theoretical data
©2006 Crystal Vision Microsystems LLC26
Design equations
212
14
NDPCdL
m
∆=φη
( )( )2'
2'2
'10
11051
kkfkffC
+++=
323
1
2
22
NDLdtm
= φη fixedkNDP ',,,,, ηφ∆
•• d can be tailored to optimize column efficiency (N) for chosen d can be tailored to optimize column efficiency (N) for chosen column transit timecolumn transit time
•• Mobile phase flow rates of only 10Mobile phase flow rates of only 10--50 nl/min necessary 50 nl/min necessary –– driving pressures of < 1 bar (< 15psi) required to operate driving pressures of < 1 bar (< 15psi) required to operate
chipchip
©2006 Crystal Vision Microsystems LLC27
Channel dimensions: 50µm x 10µmChannel dimensions: 50µm x 10µm
N=100,000N=100,000
Volumetric Volumetric flowrate [nl/min]flowrate [nl/min]
Elution [s]Elution [s]L [cm]L [cm]∆∆P [bar]P [bar]
9.29.21000100032.932.90.50.5
29.129.110210210.410.40.50.5
Volumetric Volumetric flowrate [nl/min]flowrate [nl/min]
Elution [s]Elution [s]L [cm]L [cm]∆∆P [bar]P [bar]
N=10,000N=10,000