Detailed Hydrocarbon Analysis

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The purpose of detailed hydrocarbon analysis (DHA) is to determine the bulk hydrocarbon group type composition (PONA: Paraffins, Olefins, Naphthenes and Aromatics) of gasoline and other spark-ignition engine fuels that contain oxygenate blends (Methanol, ethanol, MTBE, ETBE, and TAME) according to ASTM D6730. PONA analyte identification is conducted by matching retention indices with normal hydrocarbon paraffins. However, chromatograms obtained in PONA analyses have an extremely large number of peaks and their analytes may be mislabeled. Without accurate and reproducible retention indices, this may result in erroneous PONA ratios. The GC-2030 incorporates an Advanced Flow Controller that enables highly precise flow control and makes it easy to analyze and identify detailed hydrocarbons. Shimadzu offers DHA analysis conforming to the following methods: ASTM D5134, ASTM D6729, ASTM D6730, and ASTM D6733.

Example of a DHA analysis chromatogram

Example of a DHA analysis chromatogram

Analytical Conditions

Equipment PONA System (Nexis GC-2030AF)
Column Rtx-PONA, 100 m x 0.25 mm x 0.5 um
Pre-column Pre-PONA, 2 m x 0.25 mm x 1 um
Col. Temp 5  º C (hold 10 min) → 5 ºC/min → 48 ºC (hold 49 min) → 1.2 ºC/min → 200 ºC (5 min)
Carrier Gas He, Split 1:150 hold 5 min, split 1:20 for the rest time.
Sample size 0.2 uL
Injector 250 ºC
Detector 250 ºC
Cryogenic CRG-2030 with liquid CO2

Example of summary report from the dedicated software

Group Type Total Mass% Total Vol.% Total Mol%
Paraffins 15.868 17.1143 15.9838
Iso-Paraffins 19.495 20.8586 19.1926
Olefins 17.3556 18.5952 19.8748
Napthenes 20.6483 20.0522 21.3048
Aromatics 23.5425 20.3256 21.8861
Total C14+ 3.0907 3.054 1.7579
Total Unknowns 0 0 0
Total Oxygenates 0 0 0
Sample Total 100 100 100
Multi-substituted Aromatics: 13.7740 (mass %), 11.8683(vol. %)
Average Molecular Weight: 112.8396
Reid Vapor Pressure @ 100F: 1.9378
Calculated Octane Number: 77.0250
  IBP T10 T50 T90 FBP
BP by mass (Deg. F) 82.11 153.14 227.16 402.10 488.66
BP by vol. (Deg. F) 82.11 146.25 274.10 401.72 488.66
Percent Carbon: 86.7143 Percent Hydrogen: 13.2857
Bromine Number (Calc): 22.8036

Example of summary by group type & carbon number (in Mass Percent)

Carbon Paraffins I-Paraffins Olefins Napthenes Aromatics Unknowns Total
C1 0 0 0 0 0 0 0
C2 0 0 0 0 0 0 0
C3 0 0 0 0 0 0 0
C4 0 0 0 0 0 0 0
C5 2.61412 0.39222 2.12534 1.02294 0 0 6.15463
C6 1.75622 1.74186 3.4275 1.83233 1.5174 0 10.27531
C7 1.78205 3.41605 4.85244 3.76943 1.02589 0 14.84587
C8 1.68547 4.74174 2.49244 6.10152 3.72353 0 18.74469
C9 1.74756 5.41724 3.0002
5.20934
 5.63764 0 21.01198
C10 1.60532 3.77676 1.45765 1.93379 6.87431 0 15.64782
C11 1.56754 0.0091 0 0.01491 1.45758 0 3.04912
C12 1.56411 0 0 0.76403 3.3061 0 5.63424
C13 1.54563 0 0 0 0 0 1.54563
Total C14+ 3.09070, Oxygenates 0.00000, Total Unknowns 0.00000, Grand Total 100.00000
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