1

Micro-fabricated Differential Mobility Spectrometers for

Process Monitoring and Control

Raanan A. Miller, Erkinjon G. Nazarov, David Wheeler, Quan Shi, Denise Zazzera

Sionex Corporation, Bedford, MA

2

1/ 21.1

3 2( )

16 ( )eff eff

e ZK

N kT T

L

VVKEK 12**

ION MOBILITY based technologies use VELOCITY of ion movement under effect of electric field for chemical identification

+

1V2V

Ion size (cross-section)Ion Mass

Ion charge

Ion Mobility as Characteristic of Chemicals

3

Differential Mobility Spectrometry Operation Principle

Compensation Voltage

Sig

nal

Species 2Species 1 Species 3

Compensation Voltage

Sig

nal

Species 2Species 1 Species 3

+Air Flow

+

Electrometer(+ Ions)

IonizationSource

Air Flow++

+

SampleIn

Tunable Ion Filter

++

Electrometer(- Ions)

RF Voltage Compensation Voltage (Vc)

+Air Flow

+

Electrometer(+ Ions)

IonizationSource

Air Flow++

+

SampleIn

Tunable Ion Filter

++

Electrometer(- Ions)

RF Voltage Compensation Voltage (Vc)

microDMXTM Chip

4

SVAC-V

Existing Product Platforms

2nd Generation Sensor and ElectronicsSVAC Analyzer

Thermo Fisher: EGIS Defender

Varian: CP4900 Gas Chromatograph

General Dynamics: JUNO

5

Competitive Advantages

• High sensitivity with specificity: Detection limits comparable to much larger, expensive commercial instruments

• Quantitative output: Instead of the qualitative outputs produced by many lower cost chemical sensors being developed today

• Ability to detect a very wide range of chemicals

• Near real-time detection (msec)

• Low cost: Ability to address high volume opportunities Ability to use multiple sensors in single control system

6

microDMx for Security Applications

0 10 200.0

0.5

1.0

AV

CV

NG DNB DNT TNT PETN

G. A Eicemen, et. al, Accepted for publication, Analytical Chemistry 2004

Chemical Warfare Agents

DMS Explosives Detection

Able to resolve all 14 TSA Explosives

Low PPB Detection Limits

0.080.09

0.10.110.120.130.140.150.160.17

-35 -25 -15 -5 5

Compensation Voltage (Volts)

Inte

nsity

(V

olts

) 0.14ug/l1482V,350cc/min,50% GA,pos

4.22

-2.78

0.08

0.085

0.09

0.095

0.1

0.105

0.11

0.115

0.12

0.125

-35 -25 -15 -5 5

Compensation Voltage (Volts)

Inte

nsi

ty (

Vo

lts)

0.14ug/l1482V,350cc/min,50% GA,neg

-10.65

-6.56

-1.9-13.25

positive mode

negative mode.

7

microDMx for Process Control

Standalone microDMx:• Suitable for monitoring small numbers of compounds or changes in gas

composition of reactors requiring tight parameter control • High sensitivity (parts-per-million – parts-per-trillion)• Quantitative• Low cost – allows distributed sensors – better diagnostic accuracy of

reactors (for example for NeSSI)

GC - microDMx:• Suitable for monitoring complex mixtures of compounds• High sensitivity (parts-per-million – parts-per-trillion)• Quantitative• Low cost compared with MS– allows distributed analyzers – better

diagnostic accuracy of reactors (compatible with NeSSI)

8

Applicability of Standalone microDMx Configuration for Process Control

Introduction of analyte molecules

Atmospheric pressure chemical ionization of

analyte molecules.

63Ni, ESI, UV, plasma ion sources

Detection by Differential

Mobility Spectrometry

Process controlAnalyzer

M (?)M±; MH+; (M-H)-; MO2

- ; M2±;

M(H2O)H+;

Differential Mobility Spectrometer

ReactorAdjust parameters

of Reactoror alert operator

9

Standalone microDMx System for Monitoring Trace Level Compounds in Bulk Gases

microDmx response to a mixture of Acetone and Benzene

-20 -10 0 10 20

Compensation Voltage (V)

Abu

ndan

ce

Benzene+Acetone

Acetone Peak

Benzene Peak p-xylene m-xylene

microDMx response for Xylenes

10

Retention Time

Co

mp

en

satio

n V

olta

ge

A,B,C

GFED

CBA

GC+microDMx SeparationGC Separation

5 Components?Retention Time

7 ComponentsGC Separations are time based

FID detector

DMS

GC+microDMx for Complex Mixture Analysis

11

1,1,2,2-tetrachloroethane44)Cyclohexanone21)

Iodopentane45)o-xylene22)

Bromoform43)m-xylene20)

Bromopropane31)Tetrahydrofuran8)

1,1,1-trichlkoroethane32)3-methyl-2-butanone9)

1,2-dichloropropane33)Benzene10)

Iodopropane34)Thiophene11)

Bromobutane35)Ethylene glycol dimethyl ether12)

Bromobenzene23)

1-chlorohexane42)Ethyl benzene19)

Iodobutane41)Butyl acetate18)

Tetrachloroethylene40)2-hexanone17)

Chlorodibromomethane39)Toluene16)

1-iodo-2-methyl propane38)4-methyl-2-pentanone15)

1-chloropentane37)2-ethylfuran14)

1,3-dichloropropene36)2-pentanone13)

Chloroform30)Tert-butyl ethyl ether7)

Iodoethane29)Ethyl acetate6)

Carbon disulfide28)Propionitrile5)

Dichloromethane27)Acetonitrile4)

Ethyl Bromide26)Isopropyl Alcohol3)

Iodomethane25)Methyl Sulfide2)

Propyl benzene24)Pentane1)

NumberComponentNumber

1,1,2,2-tetrachloroethane44)Cyclohexanone21)

Iodopentane45)o-xylene22)

Bromoform43)m-xylene20)

Bromopropane31)Tetrahydrofuran8)

1,1,1-trichlkoroethane32)3-methyl-2-butanone9)

1,2-dichloropropane33)Benzene10)

Iodopropane34)Thiophene11)

Bromobutane35)Ethylene glycol dimethyl ether12)

Bromobenzene23)

1-chlorohexane42)Ethyl benzene19)

Iodobutane41)Butyl acetate18)

Tetrachloroethylene40)2-hexanone17)

Chlorodibromomethane39)Toluene16)

1-iodo-2-methyl propane38)4-methyl-2-pentanone15)

1-chloropentane37)2-ethylfuran14)

1,3-dichloropropene36)2-pentanone13)

Chloroform30)Tert-butyl ethyl ether7)

Iodoethane29)Ethyl acetate6)

Carbon disulfide28)Propionitrile5)

Dichloromethane27)Acetonitrile4)

Ethyl Bromide26)Isopropyl Alcohol3)

Iodomethane25)Methyl Sulfide2)

Propyl benzene24)Pentane1)

NumberComponentNumber Component

Analysis of Multi-functional Mixture

12

Temperature Programmed from 30-120 C @ 10 C/min

50 100 150 200 250 300 350 400 450

24

234522,44

21

20,43

19,42

18,40,41

17,39

38

1637

15

35,36

34

1433

13

11,129,10

8,32

40 60 80 100 120

7

6,31

29,30

54

5,25,26,27

3,28

GC-FID Analysis of Multi- functional Mixture

13

5

350

-20 -15 -10 -5 0

300

250

200

150

100

50

0

400

450

Compensation Voltage (volts)

Tim

e (s

)

1

65

4 32

109

8 7

15

141312 11

2019

18

17

16

23

2221

24

37

42

39

3536

Compensation Voltage (volts)

0-20-25-30-35 -15 -10 -5

25

30 29

2827 26

3433

3231

41

37

36 35

40

39 38

45

44

4342

Chl

orin

e

Bro

min

e Iodi

ne

350

300

250

200

150

100

50

400

450

Tim

e (s

)

Positive Negative

GC-microDMx Analysis of Multi-functional Mixture

14

microDMx Selectivity for Sulfur CompoundsG

C w

ith T

CD

Det

ecto

r

Odorant Peak (MES)

-0.4

-0.20

0.20.4

0.60.8

11.2

1.41.6

1.8

0 50 100 150 200

Retention time (s)

GC

with

DM

SD

etec

tor

(UV

ion

iza

tion

)

Odorant Peak (MES)

Odorant Peak (MES)

Hydrocarbon (Natural gas related) Peak Trace level control of Sulfur Compounds is important in :

Hydrocarbon processing industryPrevent Corrosion of pipes and equipmentPrevent degradation of catalysts Increase quality of end products

Fuel CellsPrevent catalyst poisoning

SafetyRequires control of level of odorants added to natural gas

Environmental ConcernsControl sulfur levels emitted into the atmosphere

15

TBMTBM

MESTHT

Hydrocarbons

GC-microDMx Chromatogram

GC-microDMx Topographic Plot

GC retention time + orthogonal DMS spectra => Selective detection of odorants in natural gas

TBMMES

THT

microDMx Selectivity for Sulfur Compounds

16

Seconds

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

mV

olt

-0.25

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

3.50

mV

olt

-0.25

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

3.50Channel 1 CP-4900 Column Module, 8m 5CB Heated Inj Channel 2 Sionex DMD

Detection of Methyl Isocyanate in Air

Concentration 1 ppm (v/v) of MIC

• Methyl Isocyanate – highly toxic (Bophal, India)

• Need to measure low level methyl Isocyanate in air

• Technology tried but unsuccessful FID, E-Nose, SAW

TCD

microDMx

0.4 ppm (v/v)microDMx

17

Detection of Methyl Isocyanate in Air

100000

120000

140000

160000

180000

200000

220000

240000

0 1 2 3 4 5 6 7 8 9 10

Injection number

Are

a C

ou

nts

1.8 ppm MIC

Stability as a function of time

Days

18

microDMx Chip

microAnalyzer

+

GC Column

GC + microDMx Sionex microAnalyzer™

19

DetectionIon Filtering

Sample trap GC column

Ionization

Interpretation

Molecules

Information

Ions

Molecules

Ions Ions

RadioactivePlasmaCoronaUV

Sionex microDMx™ Sensor

AlgorithmChromatography SWSionex EXPERT™

MicroAnalyzer System Architecture

20

Carrier gas Air

External cylinders No

Dimensions 8 x 5 x 3 (in)

Average power consumption ~20-30 W

Warm-up time <15min

Weight 1.81kg

Column 10m

Molecular sieve cartridge (up to 6 month life )

8”5”

3”

Sionex microAnalyzer™

21

2D GC-DMS Chromatogram for BTEX

300

250

200

150

100

50

0

-10 -8 -6 -4 -2 0

Coveron_60sec_500pressure_neworf_1

Positive

Ret

enti

on

tim

e

Compensation voltage

R.T(s) Vc

O- Xylene232.12 -2.00

M,P -Xylene218.81 -1.76

Ethylbenzene

232.12 -2.73

Toluene162.8 -4.18

Benzene123.35 -7,94

Micro trap material Carbopack B 60/80mesh

(RF=1187V)

22

0.70

0.65

0.60

0.55

0.50

0.45

300250200150100500

Resp

on

se (

arb

itra

ry

un

its)

Seconds

Be

nze

ne

To

lue

ne

Eth

ylbe

nze

ne

M,P

Xyle

ne O

Xyle

ne

CompoundSample amount

(ng)R.T(s) Peak width (s) Theoretical plates

Benzene 5.1 123.35 2.94 28164.6

Toluene 2.2 162.60 3.08 44702.0

Ethylbenzene 1.4 210.95 3.25 67408.1

M,P Xylene 1.3 218.81 3.98 48360.2

O Xylene 0.9 232.12 3.43 73275.2

GC - microDMx™ Chromatogram

23

•Relative standard deviation (RSD) for intensity is below 10% on multiple runs.

•RSD Retention Times were less than 0.5% over 40 runs of data.

Compound

LOD S/N=3 (parts-per-trillion)

Benzene 170

Toluene 50

Ethylbenzene 30

M,P -Xylene 10

O -Xylene 20

Ultra Trace Detection of BTEX by Sionex microAnalyzer™ Samples

24

• Differential Mobility Spectrometry provides a flexible platform for:• High sensitivity• High reliability• Quantitative• Near real time• Multi-sensor implementation • Can be made NeSSI compliant• Suitable for online / at line applications

• Thoughts and ideas for additional applications of Differential Mobility Spectrometry in process control and monitoring would be greatly appreciated

Conclusions

25

• Sionex Corporation wishes to thank:

• Dr. Jim Luong and Dr. Ronda Gras of Dow Chemical Corporation.

• Dr. G.M. Lambertus and Dr. R.D. Sacks of University of Michigan.

Acknowledgements

26

27

Measurement of Differential Mobility

lVhV KK ~

- -

-1.6

1.7

1.8

0 10000 20000 30000

Electric Field Strength (V/cm)

Mob

ility

K(E

) (a

. u.)

~ 0.6 microsecond

AA

B

Differential Mobility

a b

28

microDMx™ Ion Filter Operation

Bottom Electrode

1.6

1.7

1.8

0 10000 20000 30000

Electric Field Strength (V/cm)

Mob

ilit

y K

(E)

(a. u

.) Emin

EmaxSpecies A

Species BSpecies C

Time

Emax

Emin

t 2

t1

RF field

t2

t1

z

y

Carrier Gas Flow

ToDetector

Top Electrode

Species A

Species B

Species C

29

MeOHH2S

COS

CH3SH

Column: PoraBondTemperature 60°CCarrier: He, 150kPaTransport gas AirLDL: <100 ppb

MeOH, H2S, COS, and CH3SH

Detection of Epichlorohydrin

88 ppb (v/v) of Epichlorohydrin in Air

Epichlorohydrin (EPI) - an extremely versatile chemical intermediate. 76% of the world’s consumption of (EPI) is used to make epoxy resins.

Need to measure low levels of epichlorohydrin in air at a concentration below 1 ppm (v/v)

microDMx Epichlorohydrin Peak

TCD Detector

TCD Trace

Epichlorohydrin Glycerol