lab-on-a-chip miniaturized on- line liquid chromatography...monitoring of esterification reaction by...

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


“Conventional” Process HPLC

Dionex DX-800Process Analyzer


Concept of a Modular LC Process Analyzer based on Lab-on-Chip

NeSSI Generation III dream analyzer


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


Design issues addressed

Process stream sampling “Gearing down”, or reduction of macroflow to microflow

Obtaining a representative sample


Split flow approach to sampling

Liters per minute

microliters per minute

nanoliters per minute


Chip Layout20

mmInlet lines

Detector electrodes

Column


Capillary geometries for open channel liquid chromatography

d

“Ribbon” or rectangular microchannel

d

wConventional tubular capillary

Advantage – lower pressure drop with same diffusion path


Chip mount and lab set-up

Air


Plug generation by flow-injection


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


Chromatographic behavior

0.8

0.6

0.4

0.2

Current [nA]


5mM Phenol 5mM Pentylphenol 2.5mM Phenol & Pentylphenol

OH


Resolution improvement by coated sol gel stationary phase

3

2

1

0

Current [nA]


0.5

0.4

0.3

0.2

Current [nA]

Sol-Gel coating No coating


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


Continuous reaction monitoring configuration

Split flow


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


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


On-line sample conditioning

micromixer

waste

diluent

H-filter

Concentrated stream

return

Performs functions of :dilutionfiltrationpH conditioning


Microreactor interfacing

Parallel LC analysis platform


On-line Installation with CPC Microreactor at CPAC Laboratory, U. Washington


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


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


Thanks for your attention!

Lake Washington

University of Washington, Seattle campus

Swiss Federal Institute of Technology, Lausanne(where we started…)

Lake Geneva


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


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


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

lab-on-a-chip miniaturized on- line liquid chromatography...monitoring of esterification reaction by...

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