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

EquipmentPONA System (Nexis GC-2030AF)
ColumnRtx-PONA, 100 m x 0.25 mm x 0.5 um
Pre-columnPre-PONA, 2 m x 0.25 mm x 1 um
Col. Temp5  º C (hold 10 min) → 5 ºC/min → 48 ºC (hold 49 min) → 1.2 ºC/min → 200 ºC (5 min)
Carrier GasHe, Split 1:150 hold 5 min, split 1:20 for the rest time.
Sample size0.2 uL
Injector250 ºC
Detector250 ºC
CryogenicCRG-2030 with liquid CO2

Example of summary report from the dedicated software

Group TypeTotal Mass%Total Vol.%Total Mol%
Paraffins15.86817.114315.9838
Iso-Paraffins19.49520.858619.1926
Olefins17.355618.595219.8748
Napthenes20.648320.052221.3048
Aromatics23.542520.325621.8861
Total C14+3.09073.0541.7579
Total Unknowns000
Total Oxygenates000
Sample Total100100100
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
 IBPT10T50T90FBP
BP by mass (Deg. F)82.11153.14227.16402.10488.66
BP by vol. (Deg. F)82.11146.25274.10401.72488.66
Percent Carbon: 86.7143 Percent Hydrogen: 13.2857
Bromine Number (Calc): 22.8036

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

CarbonParaffinsI-ParaffinsOlefinsNapthenesAromaticsUnknownsTotal
C10000000
C20000000
C30000000
C40000000
C52.614120.392222.125341.02294006.15463
C61.756221.741863.42751.832331.5174010.27531
C71.782053.416054.852443.769431.02589014.84587
C81.685474.741742.492446.101523.72353018.74469
C91.747565.417243.00025.209345.63764021.01198
C101.605323.776761.457651.933796.87431015.64782
C111.567540.009100.014911.4575803.04912
C121.56411000.764033.306105.63424
C131.54563000001.54563
Total C14+ 3.09070, Oxygenates 0.00000, Total Unknowns 0.00000, Grand Total 100.00000

Nexis GC-2030

GC-2030PONA2 for ASTM D5134 “Detailed Hydrocarbon Analysis of Naphtha”

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