The dedicated gas chromatograph for analyzing oxygen-containing compounds in gasoline is suitable for determining the content of alcohols and ethers in gasoline. The components measured are: methyl tert butyl ether (MTBE), ethyl tert butyl ether (ETBE), tert amyl methyl ether (TAME), diisopropyl ether (DIPE), methanol, ethanol, isopropanol, n-propanol, isobutanol, tert butanol, sec butanol, n-butanol, and tert pentanol (tert pentanol). The determination range of various ethers ranges from 0.1% to 20%; The determination range of various alcohols is from 0.1% to 12.0%.
This method is not applicable to alcohol based fuels such as M-85, E-85, MTBE products, ethanol products, and modified alcohols.
The instrument analysis system fully complies with ASTM D4815 or SH/T0663-1998 (confirmed in 2004).


System flowchart:

working principle
Refer to Figure 5-4, introduce the sample with an appropriate internal standard [such as 1,2-dimethoxyethane (DME)] into a gas chromatography analysis system equipped with two columns and a ten way switching valve. The sample first flows into the TCEP pre cut column, where it is gently rinsed and emptied. When methylcyclopentane flows out, switch the valve to the blowback position to allow the oxide to enter the WCOT analysis column. After benzene and tert amyl methyl ether (TAME) flow out of the analysis column, the ten way valve is switched back to the starting position to blow back the heavy hydrocarbon components in the analysis column to the detector. Record detector response values proportional to component concentration; Measure peak area; And by referring to the internal standard, the concentration of each component can be calculated.

Analysis chromatogram of alcohol and ether whole component standard samples

1 methanol 2 ethanol 3 isopropanol 4 tert butanol 5 n-propanol 6 methyl tert butyl ether 7 sec butanol 8 diisopropyl ether
9 isobutanol 10 tert amyl alcohol 11 ethylene glycol dimethyl ether 12 n-butanol 13 tert amyl methyl ether 14 heavy hydrocarbons

Instrument system configuration
1. Gas chromatograph (including split/non split injection ports, dual FID detection and monitoring, with automatic blowback and reset ten way switching valve)
2. Chromatographic column:
Pre column TCEP micro filled column: 0.56m long, 1/16in (lin=2.54cm) outer diameter.
Analysis column: Methyl silicone quartz capillary column: 30m long, 0.53mm inner diameter, 5.0um liquid desert thickness.
3. Computer Workstation
4. Chromatographic gas source (high-purity nitrogen, high-purity hydrogen, pure dry air)
5. Standard samples
Qualitative standard samples of alcohols and ethers
Alcohol and ether calibration standards
Internal standard 1,2-dimethoxyethane (DME)
System analysis cutting standard sample