Microfabricated GC for Sub-ppb v Determinations of TCE in Vapor - - PowerPoint PPT Presentation

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microfabricated gc for sub ppb v determinations of tce in

Microfabricated GC for Sub-ppb v Determinations of TCE in Vapor - - PowerPoint PPT Presentation

Oct 20, 2023 260 likes •496 views

Microfabricated GC for Sub-ppb v Determinations of TCE in Vapor Intrusion Applications Jim Reisinger 1 , Hungwei Chang 2 , Sun Kyu Kim 2 , Thitiporn Sukaew 2 , Edward Zellers 2 and David Burris 1 1 Integrated Science & Technology, Inc. 2

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SLIDE 1

Microfabricated GC for Sub-ppbv Determinations

f TCE in Vapor Intrusion Applications

Jim Reisinger1, Hungwei Chang2, Sun Kyu Kim2, Thitiporn Sukaew2, Edward Zellers2 and David Burris1

1Integrated Science & Technology, Inc. 2University of Michigan, Department of Environmental

Health Sciences, School of Public Health FRTR General Meeting November 10, 2009

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Project Team

Jim Reisinger, MS – PI
Dave Burris, PhD, PG – Co-PI
Rob Hinchee, PhD

Integrated Science & Technology, Inc.

Ted Zellers, PhD – U of MI Project Manager

University of Michigan Center for Wireless Integrated MicroSystems

Kyle Gorder, PE & Jarrod Case, PE

Hill AFB, UT

Paul Johnson, PhD

Arizona State University

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Technical Objectives

Overall: Build & demonstrate new VI analyzer tools

using existing & emerging technologies. “Big picture” is ultimately have analyzers that are compound- specific for many VOCs – this project focuses on TCE, the most serious current DoD VI concern. This will promote future evolution of analyzers.

Portable “sniffer” µGC unit for hand-held short term

compound-specific “forensic” identification.

Fixed “smoke alarm” µGC unit for long-term compound-

specific exposures with remote communications.

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Specific µGC Project Goals

Fast Sample Turn-around Times (approaching 15 minutes)
Detect TCE in Presence of Common Indoor Air VOCs (i.e.,

compound-specific determinations)

Low Detection Limit for TCE (0.06 ppbv for portable µGC

and 0.03 ppbv for fixed µGC)

Portable µGC – Forensic Assessment: VI or Indoor

Source?

Fixed µGC – Long-Term (weeks, months) Exposure

Monitoring with Wireless Remote Communications

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Advances in Component & System Designs Toward a Wireless µGC

JUPITER ORION SPIRON MERCURY INTREPID MARS

iPOD-size multi-VOC analyzers

Gen 0.6

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SPIRON – Prototype µGC

1st µcolumn

2st

µcolumn chemiresistor array detector µPCF inlet pump detector temperature controller to pump A Versatile µ-Analytical System

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Key Component: µPreconcentrator/Focuser (µPCF)

Carbopack X Si/glass

µGC requires a µPCF to minimize “injection” volume

(room temp to 200oC in 0.2 sec)

µPCF fluidics limits volumetric flow rate
High-volume samples obtained with high-flow

sampler/µPCF combo

Carrier Pump

3.2mm 3.45mm

Micro- Column High-flow Sampler 1-Stage Granular Sorbent

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SLIDE 8

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Key Component: µColumn

DRIE-Si/Pyrex Channels SPIRON Dual-Column Separation Reproducible, Efficient Coatings Stable in Air up to ~200 oC

2 4 6 8 1 3 5 7

time (min)

1 2 3 4 5 7 6 8 10 9 11, 12, 13 14 15 16 17-19 20 21 22 24 23 26 25 27 28 29 31 30 33 32 34 35 36

36 cmpds in 8.2 min
Air carrier gas
FID detector

Golay Plot

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Key Component: µDetector

Gold Nanoparticle Chemiresistor Array Chemresistor Array – More “Information”

Resistance based on analyte partitioning
Partitioning based upon conc. not mass
Allows scaling down in size
Rapid, reversible, partially-selective
Micro-interdigital Au/Cr electrodes

Flow Cell Volume: as small as ~ 1.5 µL

N O O OH CF3 F3C O

C8 DPA OPH HFA CCN HME

N O O OH CF3 F3C O

C8 DPA OPH HFA CCN HME

Response Patterns – Peak ID

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SPIRON – Prototype with High-Flow Sampler (Mock-Up)

High-Flow Sampler

High-flow sampler is needed for VI applications.

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Determination of TCE & PCE among 6 common interferences found at Hill AFB

Preliminary SPIRON µGC Results

0.5 1 1.5 2 2.5 3 3.5 Time (min) C8 OPH DPA HME

TCE PCE 2-butanone benzene toluene ethylbenzene m-xylene

0.5 1 C8 OPH HME DPA

TCE

0.5 1 C8 OPH HME DPA

PCE Unique Response Patterns

0.5 1 C8 OPH HME DPA

Benzene

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Sensor calibrations are linear

TO-15 TCE Conc. (ppb)

y = 0.0069x R2= 0.9993 0.1 0.2 0.3 10 20 30 40 50

C8 Sensor Peak Area

y = 0.0048x R2= 0.9977 0.05 0.1 0.15 0.2 0.25 10 20 30 40 50

TO-15 TCE Conc. (ppb) OPH Sensor Peak Area

C8 Sensor OPH Sensor

TCE Calibration Curves

Preliminary SPIRON µGC Results

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C8 OPH DPA HME Sensitivity (V/ppbv ) 0.1095 0.0465 0.0643 0.0493 SD of noise (V) 0.0212 0.1539 0.0821 0.0643 LOD (ppbv in 1L) 0.58 9.9 3.8 3.9 LOD (ppb in 6L) 0.10 1.7 0.64 0.65

TCE Limits of Detection (LOD, ppb)

0.5 1 1.5 2 2.5 3 3.5

PCE TCE

time (min)

C8 OPH HME DPA

0.5 1 1.5 2 2.5 3 3.5

PCE TCE

time (min)

C8 OPH HME DPA

C8 OPH HME DPA 0.5 1.5 2.5 3.5 1 2 3 Time (min) TCE PCE

4-ppb TCE & PCE measurement

2 L sample
ambient RH
raw data

Preliminary SPIRON µGC Results

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Sampling

Sampler

2-ways valve µPCF Pre-trap

Column#1 Column#2

CR sensor array 3-m microcolumn 3-m microcolumn

Sampling Pump

Tee

Inlet

3-way valve

ON OFF OFF

Carrier Pump

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Focusing

Sampler

2-ways valve PCB Carrier Board µPCF Pre-trap

Column#1 Column#2

CR sensor array 3-m microcolumn 3-m microcolumn

Sampling Pump

Tee

Inlet

3-way valve

Carrier Pump

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Separation & Analyzing

Sampler

2-ways valve PCB Carrier Board µPCF Pre-trap

Column#1 Column#2

CR sensor array 3-m microcolumn 3-m microcolumn

Sampling Pump

Tee

Inlet

3-way valve

Carrier Pump

0.5 1 1.5 2 2.5 3 3.5 Time (min) C8 OPH DPA HME

TCE PCE

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Cooling & Regeneration

Sampler

2-ways valve PCB Carrier Board µPCF Pre-trap

Column#1 Column#2

CR sensor array 3-m microcolumn 3-m microcolumn

Sampling Pump

Tee

Inlet

3-way valve

Carrier Pump

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Demonstration Site Description

General Area of Indoor Air Sampling Locations

Hill AFB, UT

Areas of Shallow Groundwater Contamination

Will coordinate with Hill AFB personnel on residential homes used in demo.
Will also use SERDP Hill AFB VI-impacted research house (Dr. Paul

Johnson) for portable and fixed µGC demonstration.

Residential homes near Hill AFB are impacted by VI of TCE & are part of on-going indoor air sampling program

TCE Mitigation Action Level = 2.3 ppbv

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Phase II: Develop Field µGC Prototypes

Improve TCE LOD (fraction of Hill AFB MAL of 2.3 ppb)
optimize high-flow sampler/µPCF system
optimize chemiresistor detector for sensitivity
Robust-ize µGC – dependable operation is required
improve µPCF design for long-term operation
improve long-term stability of chemiresistor detector
dependable long-term retention time stability
Rugged-ize µGC – dependable field operation
package µGC platform for field portability
ease of sampling and standardization
AC operation

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Develop chemometrics for co-elution with TCE
can be used to deconvolute an interfering peak
Lab test with Hill AFB field samples
actual field interferences
address problematic interferences
Automate field µGC operation
Establish wireless communications with µGC
Fabricate four field µGC prototypes

Phase II: Develop Field µGC Prototype

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Schedule

First Field µGC Prototype – January 2010
Testing and Optimization – Spring 2010
4 Field µGC Prototypes (2 portable, 2 fixed) –

Spring 2010

Portable and Fixed µGC Field Demonstrations at

Hill AFB – Summer 2010

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Conclusions

Adequate field analysis tools for VI do not presently exist

(with exception of mobile analytical laboratories)

µGC Prototype development has demonstrated

compound-specific determination of TCE at low detection limit – Optimization is in-progress

Will be first field demonstration of µGC
µGC will provide a tool for VI investigations where none

currently exists

µGC can be adapted to other environmental analysis

applications