an ionization detector for gc with high speed,...

geiceman@nmsu.edu

G.A. Eiceman & M. Menlyadiev

Department of Chemistry & Biochemistry

New Mexico State University

Las Cruces, NM 88003

TANDEM DIFFERENTIAL MOBILITY SPECTROMETER:

AN IONIZATION DETECTOR FOR GC WITH HIGH SPEED, SELECTIVITY,

SMALL SIZE, AND LOW COST

ION MOBILITY SPECTROMETERS: MILITARY

PREPAREDNESS AND COMMERCIAL AVIATION

SECURITY

GC WITH IMS DETECTOR ON INTERNATIONAL SPACE

STATION: ~2002 TO 2012. THE VOLATILE ORGANIC ANALYZER

geiceman@nmsu.edu

G.A. Eiceman & M. Menlyadiev

Department of Chemistry & Biochemistry

New Mexico State University

Las Cruces, NM 88003

TANDEM DIFFERENTIAL MOBILITY SPECTROMETER:

AN IONIZATION DETECTOR FOR GC WITH HIGH SPEED, SELECTIVITY,

SMALL SIZE, AND LOW COST

1 2 3 4 5 6 7 8 9 10

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

Inte

nsity

, V

retention time, min

GOAL: ADD FURTHER DIMENSIONS OF ANALYTICAL

INFORMATION TO IONIZATION DETECTORS

Gas Chromatograph

Ionization Detector

INSIDE THE ELECTRON CAPTURE DETECTOR:

gas phase ion chemistry not often described

N2 + e- (mean 17keV) N2+. + 2e-

O2 + e- O2-

O2- + O2 O2O2

-

O2- + CO2 CO2O2

-

O2- + CO2 CO3

- + O

N4+. + H2O H2O

+. + 2N2

H2O+. + H2O H3O

+. + HO

N2 + N2+. N4

+.

H3O+. + H2O H+(H2O)2

INSIDE THE ELECTRON CAPTURE DETECTOR:

gas phase chemistry not often described

+ +

[MH+(H2O)n(N2)x]*

M

H+(H2O)n(N2)x

Intermediate

Neutral

Molecule of

Sample

+

Product Ion

V,d

Ion Swarm

Drift Velocity

Electric Field, E = V/dist

vd = drift length/td

Units of K are cm2/Vs

E = 200 V/cm

K = 2.0 cm2/Vs

vd = 4.0 m/s

MH+(H2O)n

K = (3e/16N)(2 /kTeff)1/2[(1+ )/ D(Teff)]

Collision area D will depend upon moisture, temperature, drift

gas, and molecule

+ K = vd / E

D= MH+(H2O)n(N2)x

MOBILITY OF IONS IN

GASES AT AMBIENT

PRESSURE

ION MOBILITY SPECTROMETRY IN 2013

CONVENTIONAL

TIME OF FLIGHT

OR DRIFT TUBE

FIELD ASYMMETRIC

WITH CURVE

SURFACES

FIELD ASYMMETRIC

PLANAR

a. microscale

b. nanoscale

ASPIRATOR

DESIGNS

Sub Ambient Pressure IMS

1 to 4 torr in helium

ION MOBILITY SPECTROMETRY IN 2013

CONVENTIONAL

TIME OF FLIGHT

OR DRIFT TUBE

FIELD ASYMMETRIC

WITH CURVE

SURFACES

FIELD ASYMMETRIC

PLANAR

a. microscale

b. nanoscale

ASPIRATOR

DESIGNS

Sub Ambient Pressure IMS

1 to 4 torr in helium

R.A. Miller, G.A. Eiceman, E.G. Nazarov and A.T. King, Sensors and

Actuators B. Chemical 2000, 67, 300-306.

SMALL DRIFT TUBE FOR IMS

SMALL DRIFT TUBES FOR MOBILITY

SPECTROMETRY

Analyzer

Region

Faraday

Detector

+

-

ION MOTION IN DMS AT AMBIENT PRESSURE

Asymmetric Waveform 1.1 MHz 30KV/cm

1 to 10 ms RESIDENCE TIME

+K

COMPENSATION VOLTAGE (V)

4

3

-20 -15 -10 -5 0 5 10

1

2

PROTON BOUND DIMER

-K

PROTONATED MONOMER

MOBILITY SPECTRUM : 1 to 3 s SCAN TIMES

0

5

10

15

20

-6

-4

-2

0

2

0 20 40 60 80 100

E,Td

fMo

bili

ty d

ep

en

de

nce

ADVANTAGE DMS: SEPARATION VOLTAGES, ALPHA PLOTS, &

COMPENSATION VOLTAGE

MH+(H2O)

M2H+(H2O)

COMPENSATION VOLTAGE SEPARATION VOLTAGE

HAND HELD DMS INSTRUMENTS AND

LIFE CRITICAL MEASUREMENTS

GAS CHROMATOGRAPH WITH DMS DETECTOR

Replaces GC IMS on ISS

DISPERSION PLOTS: Ion evaluation from field

dependence of mobility: Time: 1 to 3 min. S

ep

ara

tio

n V

olt

ag

e

Compensation Voltage

LONG OBJECTIVE OF DMS DMS: High

Selectivity by ion modification

DMS 1 DMS 2

Fragmentation by E

Formation of clusters

Charge stripping

Other

Fragmentation by hv

CLOSE OBJECTIVE OF DMS DMS: High Selectivity

based on E/N dependence. Time: 10 ms

DMS 1 DMS 2

Sep

ara

tio

n V

olt

ag

e

Compensation Voltage

SV 1000 V

0.5 mm

DMS 1 Electronics &

PC Control

DMS 2 Electronics & PC

Control

Gas Flow Control with

Sample

Faraday Plate &

Amplifier

5 mm

CVDMS1

SVDMS1

Det (-)

Det (+)

SVDMS2

CVDMS2

2 mm

BLOCK DIAGRAM of DMS/DMS WITH

FARDAY PLATE DETECTORS

0.5 mm

GC 63Ni

LABORATORY STUDIES WITH GC DMS DMS

DMS DMS DRIFT TUBE

ALL PASS (no Separation Voltage) SCANNING CV (& SCAN Separation V)

FIXED CV (at a Separation Voltage) SCANNING CV (at a Separation Voltage)

FIXED CV (at a Separation Voltage) SCANNING CV (at SV + 50 V)

FIXED CV (at a Separation Voltage) FIXED CV (at SV + 50 V)

DMS 1 DMS 2

Gas

Chromatograph

OPTIONS ON MEASUREMENTS USING GC DMS DMS

GC DMS DMS OF 4 ALCOHOL MIXTURE

-12 -8 -4 0

2

-12 -8 -4 0

SVDMS2

850 V

SVDMS2

950 V

ALL PASS (no Separation Voltage) SCANNING CV (at a Separation Voltage)

DMS 1 DMS 2

Compensation VoltageDMS2, V

n-BuOH

iPrOH

Rete

ntion T

ime (

min

)

MeOH

EtOH

COMPOSITE DISPERSION PLOTS OF 4 ALCOHOLS

-16 -12 -8 -4 0

600

700

800

900

1000

1100

Compensation Voltage, V

Se

para

tio

n V

olta

ge

, V

0.4120

0.4500

0.4750

0.5800

0.6430

0.7007

0.7585

0.8163

0.8740

methanol

IPA

butanol

ethanol

clusters

SVDMS1= 850V, CVDMS1= -5.4V (fixed);

SVDMS2= 900V

SVDMS1= 850V, CVDMS1= -2.5V (fixed);

SVDMS2= 900V

ION SELECTION USING FIRST MOBILITY SECTION

-12 -8 -4 0

2

-12 -8 -4 0

0

1

2

3

-5.8V

Compensation VoltageDMS2, V

Rete

ntion T

ime (

min

)

Methanol Proton

Bound Dimer

Ethanol Proton

Bound Dimer

-2.8V

FIXED CV (at Fixed Separation Voltage) SCANNING CV (at SV + 50V)

DMS 1 DMS 2

SVDMS1= 850V, CVDMS1= -1.0V (fixed);

SVDMS2= 900V

SVDMS1= 850V, CVDMS1= -0.4V (fixed);

SVDMS2= 900V

-12 -8 -4 0

2

-12 -8 -4 0

2

Iso-propanol Proton

Bound Dimer

n-Butanol Proton

Bound Dimer

-1.0V

FIXED CV (at Fixed Separation Voltage) SCANNING CV (at SV + 50V)

-0.4V

Compensation VoltageDMS2, V

DMS 1 DMS 2

Rete

ntion T

ime (

min

) ION SELECTION USING FIRST MOBILITY SECTION

SVDMS1= 850V, CVDMS1= -1.0V (fixed); SVDMS2= 950V, CVDMS2= -1.6V( fixed)

SVDMS1= 850V, CVDMS1= -0.4V (fixed); SVDMS2= 950V, CVDMS2= 0.6V( fixed)

FIXED CV (at Fixed Separation Voltage) FIXED CV (at SV + 50 V)

Iso-propanol,

Proton Bound Dimer

n-Butanol,

Proton Bound Dimer

DMS 1 DMS 2

Retention Time (min)

Inte

nsity, V

ION SELECTION USING BOTH MOBILITY SECTIONS

Iso-propanol

Acetone

ION EXTRACTION AS GC PEAKS MERGE: CONTROL

Extracted ion chromatogram

SV1=600V, CV1= -2.4V

SV2=550V;

-1.8V

Extracted ion chromatogram

SV1=600V, CV1= -0.5V

SV2=550V;

-0.8V

Total ion chromatogram

Retention Time (min)

Inte

nsity, V

1.4 2.2

Iso-propanol Acetone

ION EXTRACTION AS GC PEAKS MERGE: MERGED

Extracted ion chromatogram

SV1=600V, CV1= -2.4V

SV2=550V;

-1.8V

Extracted ion chromatogram

SV1=600V, CV1= -0.5V

SV2=550V;

-0.8V

Total ion chromatogram

Retention Time (min)

Inte

nsity, V

0.6 1.2

GC DMS/DMS SEPARATION OF 23 CONSTITUTENTS

1 2 3 4 5 6 7 8 9 10

0.5

0.6

0.7

0.8

0.9

1.0

1.1

ALL PASS (600 V) SCANNING CV (at fixed SV, -12 to 2 V)

DMS 1 DMS 2

Retention Time (min)

Inte

nsity, V

-12 -10 -8 -6 -4 -2 0 2

1

2

3

4

5

6

7

8

9

10

11

Compensation Voltage (V) for DMS2

Rete

ntion T

ime (

min

)

0.3650

0.4888

0.6125

0.7362

0.8600

0.9838

1.107

1.231

1.355

Separation Voltage 700V

GC DMS DMS SEPARATION OF 23 CONSTITUTENTS

-15 -12 -9 -6 -3 0 3 6

1

2

3

4

5

6

7

8

9

10

11

Compensation Voltage (V) for DMS2

Rete

ntion T

ime (

min

)

0.3600

0.4607

0.5615

0.6623

0.7630

0.8638

0.9645

1.065

1.166

Separation Voltage 1000V

GC DMS DMS SEPARATION OF 23 CONSTITUTENTS

GC DMS

Extracted ion chromatogram

SV2=550V; CV2= -1.4V

GC DMS DMS

Extracted ion chromatogram

SV1=600V, CV1= -0.5V

SV2=1200V;

Total ion chromatogram

-1.4V

EXTRACTED ION CHROMATOGRAM IN 23 CMPD MIX

Retention Time (min)

Inte

nsity, V

CONCLUSIONS

B. Chromatographic interface

trivial; size, complexity compatible

with ionization detectors.

C. Analytical performance may

approach functionality of tandem

MS for faction of costs

A. DMS DMS with fixed SV and CV provide response with

selectivity and response time at 100 ms---->10ms.

D. Suitable for portable GC

ChemRing Detection Systems…..aid in electronics and

software.

ACKNOWLEDGEMENTS

Weekly report Marlen Menlyadiev

May 10, 2013

DMS1 DMS2

a

b

Sample gas flow 1.5 L/min

Dopant gas flow 0.2 L/min

c

Flo

w v

elo

cit

y,

m/s

COMSOL FLOW MODELING IN DMS/DMS

(FLOW DYNAMICS TEST)

Flow velocity map

Flow velocity map

Pressure map

Ethyl acetate Methyl butyrate Isobutyl Acetate Methyl Valerate Isopropenyl acetate Tert-butyl acetate Sec-butyl acetate Isopropyl acetate Ethanol Isopropanol 1-butanol 1-pentanol 1-hexanol 1-heptanol Pinacolone 2,4-dimethyl-3-pentanone Cycloheptanone Acetone Hexanone-2 2-metyl-3-pentanone 2,6-dimethyl-4-heptanone 3-methylcycylohexanone cyclohexanone

IMS MS CIRCA 1970

Plasma Chromatography™—A New Dimension for Gas Chromatography

and Mass Spectrometry Journal of Chromatographic Science 1970 8 (6) 330-337.

Martin J. Cohen, Franklin GNO Corporation, West Palm Beach, Florida 33402 F. W. Karasek, University of Waterloo, Waterloo, Ontario, Canada

Composite dispersion plot of heptanol-1, cyclohexanone and DMMP

methan

ol IPA

ethanol

cluster

s

ammo

nia

RI

P

-20 -15 -10 -5 0 5 10

600

800

1000

1200

1400

Compensation Voltage, V

Se

para

tio

n V

olta

ge

, V

0.4260

0.4500

0.4700

0.5767

0.6270

0.6773

0.7275

0.7778

0.8280

(Hept)H+

RIP

(Hept)2H+

(Cyclohex)H+

(Cyclohex)2H+

(DMMP)2H+

(DMMP) H+

5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

Det

ecto

r R

espo

nse

(V)

Retention Time (min)

GC-DMS2 experiment: SV2 500V, CV2 scanning at 1Hz. CV2= -0.4V extracted chromatogram 1ng

Heptanol-1

Cyclohexanone

DMMP

GC-DMS2 experiment: SV2 500V, CV2 scanning at 1Hz. CV2= -0.4V extracted chromatogram

GC-DMS1-DMS2 experiment: SV1 1000V, CV1 -0.8 V; SV2 500V CV2 scanning at 1Hz. CV2= -0.4V extracted chromatogram

GC-DMS1-DMS2 experiment: SV1 1400V, CV1 2.2V; SV2 600V CV2 scanning at 1Hz. CV2=0V extracted chromatogram

GC-DMS1-DMS2 experiment: SV1 1500V, CV1 4.0V; SV2 700V CV2 scanning at 1Hz. CV2= 0V extracted chromatogram

1ng

2ng

3ng

3ng

Heptanol-1

Cyclohexanone

DMMP