Improved Performance of the Analysis of Aromatics in Gasoline by ASTM Method D5769 Using the Agilent 5977B GC/MS with the InertPlus Source

Agilent technologies, Inc.

June 2016

Fred Feyerherm

Reformulated Gasoline from epa.gov website

Reformulated Gasoline - background:

US Congress Clean Air Act of 1973

Amended 1990

Directed EPA to clean up urban air

EPA method 80.46 (f) (from 40 CFR)

ASTM subsequently developed D5769

High accuracy and precision using GCMS

Impacted 180 refineries in US and anyone

shipping gasoline to US

Reformulated Gasoline - background:

Parameters Regulated:

Total Aromatics (GCMS) limited to <25 vol%

Benzene (GC)

Oxygenates (GC-OFID)

Olefins (D1319 FIA)

Sulphur (X-ray)

Reid Vapor Pressure

Why GCMS for Aromatics?

EPA wanted to identify unknowns from possible dumping

EPA has a lab in Ann Arbor Michigan

What is Gasoline…chemically?

Saturates

Olefins

Napthenes (e.g. cyclohexane)

Aromatics

Oxygenates

Traces of other compounds

GCMS Chromatogram of Gasoline

Use Mass Spec to identify peaks

ASTM Method D5769 for Total Aromatics in Gasoline

Use Extracted ion to find targeted compoundsExtracted Ion Chromatogram EIC m/z 78

Quantitation by GCMS

Get a standard for each compound

Use extracted ion chromatogram to get peak and integrate

Use an Internal Standard (e.g. Benzene-d6)

But you can’t readily get standards for every possible aromatic

Get standards for all C6 – C9 and selected C10 Aromatics

Create Uncalibrated Compound Groups as directed in D5769

D5769 Uncalibrated C10-benzenes

C7 (Toluene m/z 91) and C8 Aromatics

C9 Aromatics m/z 120

C10 Aromatics m/z 134

C11 Aromatics m/z 148

C12 Aromatics m/z 162

Additional Aromatics: Indane and alkylated Indanes m/z 117

Additional Aromatics: Naphthalenes

Quantitation Compound List for D5769

D5769 differences from normal GCMS type analysisSpecial Software

Gravimetric calibration

• Raw weights

• Multiple gravimetric ISTDs

• Update from disc (Accustandard)

Quantitate Uncalibrated aromatics using RF from

calibrated cpnd

Report both Wt % and Vol %

Keys for SuccessExcellent Linearity for all analytes on 5977B GCMS

Regulatory Compliance

EPA has contracted Southwest Research Institute (SWRI) for

compliance monitoring

SWRI Lab in San Antonio does most monitoring samples

EPA Ann Arbor also does some

Regulatory Compliance

My Opinion: Everyone needs to get the same answer, not necessarily the best answer for total aromatics in gasoline.

As SWRI

Same STDs

Same column

Same method

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