Air Toxics Monitoring Data Analysis Workshop

September 27-28, 2005

Brian K. Gullett, Ph.D. U.S. EPA/Office of Research & Development

DEVELOPMENTS IN REAL TIME, TRACE AIR TOXIC MONITORING: Jet REMPI

Jet Resonance Enhanced MultiPhoton Ionization

One-colortwo-photon

REMPI

Two-colortwo-photon

REMPI

Ionizationcontinuum

electronic ground state

electronic excitedstates

hν1

hν1

hν3

hν2

Microchannel plate Detector

Time-of-Flight Mass Spectrometer

Ion ReflectorIon Beam Steering Plates

Pulsed Gas Inlet(out of plane)

(Supersonic Jet Expansion)

Ion Extraction Optics

Nd:YAG LaserTunable Optical ParametricOscillator (OPO)

Jet Resonance Enhanced MultiPhoton Ionization

Measures a broad array of aromatics, including halogenated organics and PAHs

Real time to near-real-time

Sensitive (ppt to ppb)Concentration to ppq

Selective (can distinguish isotopomers)

Source or ambient monitor

Jet REMPI system in EPA’s RTP laboratories

High Selectivity: Mass and WavelengthHigh Selectivity: Mass and Wavelength

4

Test of an aromatic mix (100 ppb each)

High Selectivity: Dioxin Isomer-specificHigh Selectivity: Dioxin Isomer-specific

304.6 304.8 305.0 305.2 305.4 305.6 305.8 306.0251.8

252.0

252.2

252.4

252.6

252.8

253.0

253.2

253.4

253.6

253.8

254.0

254.2

Mas

s (am

u)

Wavelength (nm)

Laser tuning resolution (0.005 nm)

(251.974 amu)

(253.974 amu)

TOF massresolution

(0.25 amu)

(253.974 amu)

(251.974 amu)

O

O

35Cl37ClO

O

35Cl

37Cl

O

O

35Cl35ClO

O

35Cl

35Cl

2,7 dichlorodibenzodioxin 2,8 dichlorodibenzodioxin

302 303 304 305 306

0

1

2

3

4

5

Ion

Sign

al [a

.u.]

Wavelength [nm]

2,7-DCDD2,8-DCDD

5

1E-3 0.01 0.1 1 10 1001E-3

0.01

0.1

1

10

High to low [ ] Low to high [ ] Linear fit

14 ppt

Noise levelIon

Sign

al (a

rb. u

nits

)

[UCDD]theory

(ppb)

Derived detection limit for benzene of 2.5 ppt

Derived detection limit for benzene of 2.5 ppt

Very High Sensitivity: Benzene and dibenzo-p-dioxinVery High Sensitivity: Benzene and dibenzo-p-dioxin

1E-3 0.01 0.1 1 10 100 10000.01

0.1

1

10

100

1000

10000

Averaged noise level over 100 laser shots (10 s.)

S/N = 1at 2.5 ppt

Linear fit withR2 = 0.99964

Ion

Sign

al (a

rb. u

nits

)

[Bz] (ppbv)

Observed detection limit for dibenzodioxin of 14 ppt

Observed detection limit for dibenzodioxin of 14 ppt

6

Applications of Jet REMPI: Air Toxics from DoD Diesel Generator Exhaust

Methylated PAHsduring start-ups

Applications of Jet REMPI: Air Toxics from DoDDiesel Generator Exhaust

0

100

200

300

400

Benze

ne

Tolue

ne

Ethyl B

enze

ne

p-Xyle

ne

m-Xyle

ne

m,p Xyle

ne

o-Xyle

ne

Styren

e

Target Analytes

Con

cent

ratio

n (p

pbv)

Online GC GC MS JET-REMPI AP-42

Jet REMPI compares well with conventional GC MS, on-line GC, and AP42 Emission Factors

Turbine Engine Compressor, USAF type A/M32A-95, JP8. Compressor furnishes pneumatic power for ground support of aircraft systems.

Applications of Jet REMPI: Air Toxics from USAF Jet Compressor

Phenol

Toluene

Xylenes

(methylated) naphthalenes

Turbine engine emits more (aromatic) pollutants at low load than at high load.

Applications of Jet REMPI: Air Toxics from a Waste Combustor.

Focus on Chlorinated Dioxins/Furans.

Dec., 2004 Testing

(results pending analysis)

Applications of Jet REMPI: Air Toxics from a Waste Combustor.

Focus on Chlorinated Dioxins/Furans.

18:10 18:15 18:20 18:25 18:30 18:35 18:40 18:45 18:50 18:55 19:000

10

20

30

40

50

60

70

80

0

200

400

600

800

1000

1200

1400

Ion

Sig

nal (

arb

units

)

Plant Time (hour:min)[C

O] (

ppm

)

Method: correlation of indicator or precursor compounds with more trace concentration dioxins

TEST: Dioxin Emission Monitoring Systems – 9/12-23/05

Verification Test Design:• Boiler cofiring #2 oil and 1,2 dichlorobenzene

• Four EMSs operated simultaneously.

• Collect reference samples using Method 23.

• Range of sampling periods, 4 to 16 h.

• Range of dioxin concentrations.

• Performance parameters evaluated:

– Accuracy vs. Method 23

– Ease of use, reliability, maintenance, etc.

Dioxin EMS Technologies• Automated, long term sampling systems with laboratory analysis

– AMESA (Becker-Messtechnik, GmbH)

– Dioxin Monitoring System (MonitoringSystems, GmbH)

•Real and near-real-time analysis with laser ionization and mass spectrometric detection

– RIMMPA-TOFMS (IDX Technologies, Inc.)

– JET-REMPI (EPA/SRI International)

Jet REMPI Summary• Real-time to near-real-time measurement

start-ups, load changes, temporal air toxic changes, process monitor/feedback

• Source or ambient monitor• Highly sensitive

ppt to ppb in real time, ppq with concentra.• Measures broad array of aromatics• Highly selective

isotopomer-specific• 4 field demonstrations to date

Including waste combustor, ETV test of dioxin monitors

For more information contact:Brian K. Gullett, Ph.D. U.S. EPA/ORDgullett.brian@epa.gov

DEVELOPMENTS IN REAL TIME, TRACE AIR TOXIC MONITORING:

Jet REMPI