Detailed Hydrocarbon Analysis

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

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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