The document describes an analytical method for the determination of ethers and alcohols in gasolines using the Agilent 6820 gas chromatography system. This method utilizes a 10-port switch valve and two columns. The specific compounds determined include methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), diisopropylether (DIPE), methanol, ethanol, isopropanol, n-propanol, isobutanol, tert-butanol, sec-butanol, n-butanol, and tert-pentanol. 1,2-dimethoxyethane (DME) is used as the internal standard for quantitative analysis. The Agilent 6820 GC is used to run ASTM Method D4815 for determining oxygenates in gasoline.
The document details a method for determining oxygenates, including methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), and various alcohols, in unleaded gasoline. The procedure utilizes the Agilent 6820 Gas Chromatography (GC) system equipped with a flame ionization detector (FID), a 10-port switch valve, and two specific columns: a polar TCEP micropacked column for prefractionation and a nonpolar HP-1 capillary column for separation.
The application outlines the experimental configuration, including hardware components like the auxiliary gas pressure regulator and software used (Cerity NDS). It provides specific instrument conditions such as oven programs, flow rates, and temperatures. The text also explains the method description involving valve switching to separate lighter hydrocarbons from oxygenates, presents calibration procedures with standards, and discusses results regarding repeatability which exceeds ASTM D4815 specifications.
| System Type | Agilent 6820 GC system |
|---|---|
| Prefraction Column | Micropacked column packed with polar 1,2,3-tris-2-cyanoethoxypropane (TECP) |
| Analytic Column | Nonpolar HP-1 capillary column |
| Internal Standard | 1,2-dimethoxyethane (DME) |
| Inlet Temperature | 200 °C |
| Detector Temperature | 250 °C |
The specific compounds determined include methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), diisopropylether (DIPE), and various alcohols such as methanol, ethanol, and propanol.
For this system, a backflush time of 0.22 minutes is used for the analysis of DIPE to ensure hydrocarbons are completely eluted while ethers are retained.
Yes, the experimental data demonstrates that the results exceed the ASTM D4815 calibration and repeatability specifications.