EXPLANATION
Test methods to determine benzene and the aromatics in gasoline are necessary to assess the product quality and to meet fuel regulations. This test method can be used for gasolines that contain oxygenates such as alcohols and ethers as additives. They do not interfere with the analysis of benzene and other aromatics by this test method. The method is applicable in the concentration range of liquid volume percent:
Benzene 0.1 to 4; toluene 1 to 13; and total C6 to C12 aromatics 10 to 42.
This test method has not been tested on individual hydrocarbon process streams in a refinery, such as reformates, fluid catalytic cracked napthas, etc., used in the blending of gasoline.
TEST SUMMARY
The sample is injected either through the capillary splitter port or a cool-on-column injector into a gas chromatograph equipped with a dimethylpolysiloxane WCOT column interfaced to a fast scanning mass spectrometer. The capillary column is interfaced directly with the mass spectrometer or by way of an open split interface or other appropriate device. Calibration is done with mixtures of specified pure aromatic hydrocarbons. A multipoint calibration consisting of at least five levels and bracketing the expected concentrations of the specified individual aromatics is required. Specified deuterated hydrocarbons are used as the internal standards.
TEST PRECISION
Where X is the volume % of the component.
Bias of this test method is not known.