Dr' Alberto M' Correa

1
Chemiresistor A Micro-Chemical Sensor for
In-Situ Monitoring and Characterization of
Volatile Organic Compounds (VOCs) (Developed by
Sandia National Laboratories)

• Dr. Alberto M. Correa
• The Bi-National Sustainability Laboratory
• Report on the project for air toxics monitoring
• 44th JAC meeting
• Cd. Juárez, Chihuahua March 19, 2009

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Background

• Methods for monitoring contaminated sites with
  toxic chemicals are expensive, time consuming,
  and misrepresentative of in-situ conditions.
• Sandia National Labs developed a microsensor
  monitoring system that can be used to
  characterize VOCs.
• The sensor system consists of an array of
  miniature sensors, called chemiresistors that can
  operate in soil, water and air.
• The sensor is packaged in a unique, waterproof
  housing designed to protect the sensor from harsh
  environments.
• The patent has been licensed to Team
  Technologies, Inc. a company in Albuquerque, NM,
  who is partnering with DInformatica 21, a
  Mexican company in Chihuahua city for the
  technology commercialization in Mexico.

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Chemiresistor Technology

• Each chemiresistor is fabricated by mixing a
  commercial polymer dissolved in a solvent with
  conductive carbon particles.
• When VOCs are present, the chemicals absorb into
  the polymers, causing them to swell.
• The swelling changes the electrical resistance
  that can then be measured and recorded.
• The amount of swelling corresponds to the
  concentration of the chemical vapor in contact
  with the polymers.
• The process is reversible, and the polymers will
  shrink once the chemical is removed, reverting
  the resistance to its original state.

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Chemiresistor Technology
VOCs Volatile organic compounds aromatic
hydrocarbons (e.g., benzene, toluene, xylenes)
chlorinated hydrocarbons (e.g., TCE, carbon
tetrachloride), aliphatic hydrocarbons (e.g.,
hexane, octane), alcohols, ketones.
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Chemiresistor applications
Sites containing toxic chemical spills, leaking
underground storage tanks, and chemical waste
dumps will require characterization and long-term
monitoring to reduce health risks and ensure
public safety.
Over a million underground storage tanks
containing hazardous (and often volatile)
contaminants are being regulated by the EPA and
SEMARNAT, requiring monitoring to detect leaks
from the tanks and pipe network.
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Market segmentation

• The chemiresistors applications have been
  analyzed extensively.
• The potential market segments determined are
• The fuel storage and distribution industry
• The petrochemical industry
• The chemical industry
• The hazardous waste storage system
• The paint applications industry (paint shops)
• The environmental authorities (as users and as a
  potential enforcement mechanism)

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The competitors

• The products that the chemiresistor will confront
  in the market are, among others
• The SAW Chemical Sensor Array, able to detect
  organophosphates, chlorinated hydrocarbons,
  ketones, alcohols, aromatic hydrocarbons, and
  saturated hydrocarbons. The SAWs and
  chemiresistor arrays have similar limit of
  detection. It has a time of response of about
  tens of seconds. Its price is about 500.
• The MicroChemLab is a chromatography system that
  consists in a microfabricated hotplate
  preconcentrator, a micromachined silicon gas
  chromatography column and a SAW sensor. It
  perceives an extensive variety of hazardous
  compounds in about 1 to 5 minutes. Its price
  oscillates between 10 and 20K.
• The MicroHound is composed of a chemical
  preconcentration system and a miniature Ion
  Mobility Spectrometer (IMS). It is also capable
  of identifying compounds in concentration in the
  ppb range. It has a time response of just a
  couple of seconds, and it costs approximately
  5K.

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Competitive advantages

• Sensitivity ppm
• Compactness 1 X 1 X 1
• Calibrability flexible calibration to different
  ranges of concentrations
• Wide range of applications in soil, water and air
• Price as compared to the other products in the
  market seen in the previous slide, the
  chemiresistor is from one to three orders of
  magnitude less expensive. Retail price will be of
  the order of 150.00 USD

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Project status

• Team Technologies (Albuquerque) and DInformatica
  21 (Chihuahua) have sign a partnership contract
  to develop and commercialize the product in the
  US and Mexico
• Team Technologies is manufacturing several lots
  of prototypes for monitoring VOCs in air,
  calibrated to different concentrations
• DInformatica 21 has developed the contacts in
  Chihuahua city for monitoring fumes in gas
  stations
• The Bi-National Sustainability Laboratory has
  done preliminary market surveys based on the
  analysis of the potential applications, promoted
  the product with the environmental authorities of
  both countries along the border region, analyzed
  the competition and determined the technical and
  economical feasibility of this project

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Future steps

• Approach EPAs Verification Programs Managers to
  introduce the concept and obtain proper support
  for technology verification
• Apply additional survey questionnaire to
  representative samples of the several market
  segment identified in both countries to expand
  the market survey
• Field test the prototypes by approaching the
  market and the environmental authorities of both
  countries, since both of them are interested in
  testing the product, even at a prototype level

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Proposal and benefits from the bi-national
viewpoint

• This is a bi-national project that could bring
  wide benefits to the border region, not only from
  the environmental monitoring viewpoint, but also
  on strengthening the bilateral relationship among
  the US and Mexico, and the regional job creation
  when starting market penetration
• We propose EPAs collaboration for introducing
  the concept to the Technology Verification
  Program
• We propose SEMARNATs analysis for supporting the
  alternative of establishing a pilot project for
  monitoring fumes in gas stations, having as it
  was mentioned at the beginning of this
  presentation, a gas station in Chihuahua city
  already committed to start this pilot program.

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Thank you
Dr. Alberto M. Correa BNSL
acorrea_at_bnsl.org UTEP albertoco_at_utep.edu
cell 915-799-1908
The Bi-National Sustainability Laboratory