Quantification of the concentration of VOCs in gasoline and diesel

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www.estcal.com www.estcal.com Electronic Sensor Technology, Inc. Quantification of the concentration of VOCs in gasoline and diesel

Transcript of Quantification of the concentration of VOCs in gasoline and diesel

Page 3: Quantification of the concentration of VOCs in gasoline and diesel

www.estcal.comwww.estcal.comElectronic Sensor Technology, Inc.

4 News that have shocked us in the past!

• Fuel contamination incident in Bangor, County Down lead Tesco to pay the claims of about £8m.

• ASDA sent cheques to about 3,000 customers who collectively claimed £1.4m in compensation.

• In 2009, Fatty Acid Methyl Ester, a harmful component for engines found in jet fuel of U.S Air Force’s C-130 USAF.

• Fleet Readiness Center (FRC) East discarded about 12,000 gallons of fuel in December, 2014.

Fuel contamination is creating major problems for the globe

Page 5: Quantification of the concentration of VOCs in gasoline and diesel

www.estcal.comwww.estcal.comElectronic Sensor Technology, Inc.

7 Unique features of EST zNose®

Uses Surface Acoustic Wave (SAW) sensor and

ultra-fast Gas Chromatography (GC)

technology.

Rapidly provides complete

chemical profile.

Software of zNose® includes expandable library

of over 700 chemicals & odor signatures.

Operates within a wireless network.

Page 6: Quantification of the concentration of VOCs in gasoline and diesel

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4 steps to quantify the Chemistry of Gasoline Vapors!

Step 1 -Ambient air (vapor) is first sampled

and organic vapors collected on the trap

that acts as a pre-concentrator.

Step 2- The trap is switched into the

helium section where the collected organic

compounds are injected into flowing helium gas.

Step 3- The organic compounds pass through a

capillary column with different velocities and thus

individual chemicals exit the column at specific

times.

Step 4- As they exit the column they are

detected and quantified by a solid

state detector.

Page 7: Quantification of the concentration of VOCs in gasoline and diesel

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6 Samples of Pemex gasoline (87 and 92 octane) & 5 samples of diesel were taken from various service stations across US and subjected to a 4-step GC

method.

Testing Gasoline and Diesel Samples from service stations!

Page 8: Quantification of the concentration of VOCs in gasoline and diesel

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4-step GC method

Step1: Sample Preparation Fully vaporized samples and headspace vapors of gasoline and diesel collected.

Step 2: Sample Pre-concentration Time: Required sample volume of 1-0.5 milliliter from the concentration of vapor samples from gasoline and diesel.

Step 3 - Column Ramping: Used a db624 column and temperature ramping rates varied from zero (isothermal) to as high as 18o C/second.

Step 4 - Detector Response: Detector temperature of 10o C used for optimum response to the most volatile compounds, such as benzene.

Page 9: Quantification of the concentration of VOCs in gasoline and diesel

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• Calibration standards made by injecting known concentrations of benzene, toluene, ethylbenzene, o-xylene, and n-alkanes into septa sealed 40 milliliter vials and 250 milliliter bottles.

• Vapor standards used to verify system linearity and to provide reference retention times for indexing peak retention times.

• Standard deviation of replicate measurements using vapor standards was typically 1-5%.

• Using BTEX calibration standards used to test system linearity for vapor concentrations up to approximately 50 ppm.

4 Key Matrices to Set Calibration Standards