Développement de micro-préconcentrateurs pour l'analyse de ... · Développement de micro-préconcentrateurs pour l'analyse de traces de gaz et explosifs. 1 Jean-Paul VIRICELLE,

Institut Mines-Télécom

Développement de micro-préconcentrateurs

pour l'analyse de traces de gaz et explosifs.

1 Jean-Paul VIRICELLE, colloque IMT Matériaux , mars 2016

JP Viricellea, P. Breuila, C. Pijolata, F Jamesa, M. Camarab, D. Briandb

aEcole Nationale des Mines, SPIN-EMSE, CNRS:UMR5307, LGF,

F-42023 Saint-Etienne, France

bEcole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering

(IMT), Sensors, Actuators and Microsystems Laboratory (SAMLAB),

Neuchâtel, Switzerland


Outline

Context / Principle

Design and fabrication

Adsorbent characterization / Parameters

Applications

• VOC preconcentration test, GC analysis

• Explosive detection

Conclusions

2 Jean-Paul VIRICELLE, colloque IMT Matériaux , mars 2016

Micro-preconcentrators


Challenge : Gas trace detection

with sensor or analyzers with limited sensitivity

Miniaturized system for in situ detection

3

Introduction: context

• Conventional trap (preconcentration tube)

• Miniaturized

analyzer : Micro-GC module

Reduce dead volume and thermal mass

MEMS technology

Microfabricated preconcentrator

Miniaturized system : Micro-GC /Micro-preconcentrator

coupling

Jean-Paul VIRICELLE, colloque IMT Matériaux , mars 2016

Institut Mines-Télécom 4

Gas pre-conditioning is of importance for the detection of chemical

substances in trace level.

Process : Accumulate a target gas, then desorbed it by a temperature pulse

Introduction: preconcentration principle


Sensor

analyser 10

1000

Micro-préconcentrateur

without preconcentration

with preconcentration

adsorbant

Heating

Adsorption Desorption


Introduction: Preconcentration factor

Preconcentration factor : ratio of outlet to inlet concentration

C1. t1. f1= C2. t2. f2 C: concentration

t: time f: flow

Preconcentration factor: 𝑷𝑭 =𝒕𝟏𝒇𝟏

𝒕𝟐𝒇𝟐=

𝑪𝟐

𝑪𝟏

Time (min)

Desorption

step

Adsorption

step


Augmentation du facteur de préconcentration PF implique :

- un débit d’adsorption élevé ;

- un temps d’intégration le plus long possible ;

- un débit de désorption faible ;

- enfin une désorption le plus rapide possible.

Si t1 < temps de perçage,

conservation de la matière :


Design

Design and schematic device composition:

a) platinum heater,

b) etched silicon wafer

c) glass cover

d) capillaries

Characteristics Values

Depth 500µm

Chamber volume 14 μL

External diameter

capillary

500 µm

Internal diameter

capillary

385 µm

Resistance value 10 Ω

Inlet/outlet channels preconcentrator/ 1euro

Preconcentrator design



Preconcentrator fabrication

Silicon

Photoresist

Deep Reactive Ion Etching (DRIE)

Pyrex glass

Structured resine : design DRIE (500 µm deep) Resin removal Wafer bonding (Si/Pyrex glass)

Structured silicon wafer Silicon material

-good thermal conductiviy,

-suitable material for DRIE)

MEMS preconcentrator

Microfabrication at EPFL, Neuchâtel



Heater deposition

Heater deposition by screen printing

0

50

100

150

200

250

300

350

0 10 20 30

Tem

pera

ture

(°C

)

Time (min)

Température calculée à partir de la résistance mesurée

Consigne de température (°C)

Calculed temperature with R value

Temperature set

0

50

100

150

200

250

300

350

0 10 20 30

Tem

pera

ture

(°C

)

Time (min)

Température calculée à partir de la résistance mesurée

Consigne de Température (°C)

Calculed temperature with R value

Temperature set

Si

Better

insulation with

a layer of

silicon nitride

Short circuit

due to the

silicon

conductivity

SiO2

Pt

SiO2

Si3N4

Si

Pt



Micro-Preconcentrators development Platinum heater deposition by screen-printing.

Heating element and temperature distribution

Micro-préconcentrateur device

Capillary : Øinterne 220 µm for 325µm deep IMT micro component .

Metallic capillaries sealed with ceramic

cement, with 1/16” connectors.

3 cm

1,5

cm

380°C T

405°C

300

°C

Etched Silicon

Microcomponent

Adsorbent chamber

Thèses M. CAMARA (2010)

F James (2015)



Sorbent deposition

Carbon Nanopowder deposition by microfluidic method

Characterizations Carbon Tenax TA

Particule diameter 100 nm 200 µm

Surface Area 95 m2/g 20 m2/g

Mass deposition :

2 mg carbon nanopowder



0,0E+00

5,0E-09

1,0E-08

1,5E-08

2,0E-08

0 100 200 300 400 500

Inte

ns

ity (

a.u

)

Temperature (°C)

Toluene

Blank

11

Sorbent material study

Temperature Programmed Desorption

Thermal desorption of gas species analyzed by mass spectrometry

Pv=2,9 kPa

b.p = 110°C

Vapor exposure :

1 ppm of Toluene

during1 hour at 10L/h

Thermal desorption:

Desorption

temperature at 250-

300°C


Carbon

nanopowder


Preconcentration test. Laboratory test bench

Setup

Photo Ionisation Detector (PID)

for Vapour Organic Compounds

(VOCs)

Carbon Preconcentrator Permeation tube



Preconcentration test. Parameter influence

Heating rate and flow rate influence

0

10

20

30

40

50

60

70

80

90

100

10 10,5 11 11,5 12 12,5 13

Co

ncen

trati

on

(p

pm

)

Time (min)

désorption à 1L/h

désorption à 3L/h

désorption à 5L/h

désorption à 10L/h

Flow rate :1L/h

Flow rate :3L/h

Flow rate :5L/h

Flow rate :10L/h

0

10

20

30

40

50

60

70

5 6 7 8 9 10 11

Co

ncen

trati

on

(p

pm

)

Time (min)

Montée en 40°C/s à 300°C

Montée en 15°C/s à 300°C

Heat rate : 40°C/s to reach 300°C

Heat rate : 15°C/s to reach 300°C

High heating rate for high peak

detection

Low flow rate for high peak

detection

rateflow

particlesdesorbedofNumberC

out

Vapor exposure : 1 ppm of Toluene during 5 min at 10L/h



1rst application : GC Analysis. Industrial Setup

Setup and GC process

Preconcentrator 6 ways valve

Sampling Heating and

injection

Preconcentrator as a sample loop



1rst application : GC Analysis

Target Gas Initial

Concentrations

Preconcentration

factors (PF)

Toluene 37 ppb 200

Vinyl acetate

monomer 39 ppb 800

Chloroform 46 ppb 600

MIBK 35 ppb 200

ppb trace level analysis with interferences (natural gas)

ppm trace level analysis

Target Gas Initial

Concentrations

Preconcentration

factors (PF)

Toluene 8 ppm 689

Vinyl acetate

monomer 9 ppm 658

Chloroform 11 ppm 438

MIBK 7 ppm 576

Chromatograms

PF=𝑨𝟐

𝑨𝟏 A : peak area


Industrial applications:

Gas mixture analysis (Toluene,Methylisobutyketone,

Chloroforme, Vinyl acetate)


ppb trace level analysis

Explosive detection

Micropreconcentration of DNT

(Dinitrotoluène)

0

500

1000

1500

2000

2500

3000

3500

0 5 10 15 20 25 30

Co

nce

ntr

atio

n (

pp

b)

Temps (min)

DNT adsorption 300 ppb

Silicium poreux

Silicium normal

0,0E+00

2,0E-13

4,0E-13

6,0E-13

8,0E-13

1,0E-12

0 100 200 300 400

Inte

nsi

té (

u.a

)

Temperature (°C)

Silicium poreux

Thermal Programmed Desorption

of DNT on porous silicon

Preconcentration test

of DNT on porous silicon

Desorption

@ 250°C

pore size Ø : 1-2 µm and thickness: 90-110 µm

Use of porous silicon (composant wall)

as adsorbant


2nd application : Explosive detection


Conclusions

Microfabricated MEMS preconcentrator

• Low volume :14 µL

• Fast Heating rate :40°C/s

• Flow rate : 1 to 20 L/h

Various adsorbent material : Carbon nanopowder or nanotubes,

Tenax, porous silicon , …

• Good adsorption capacity for large range of VOCs, explosives,

drugs…

Wide range of applications

• Coupling micropreconcentrator/µ-GC or with other analyzer

• Air quality monitoring (VOCs)

• Security applications (explosives, drugs)

• Any need of traces detection…



Thank you for attention 18 Jean-Paul VIRICELLE, colloque IMT Matériaux , mars 2016

EC project on Explosive detection

FP7-SEC-2011-1 N° 285203

Acknowledgments

TraceTech Security

L’analyse en ligne au coeur des procédés

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Développement de micro-préconcentrateurs pour l'analyse de ... · Développement de micro-préconcentrateurs pour l'analyse de traces de gaz et explosifs. 1 Jean-Paul VIRICELLE,