EXPLANATION
The aromatic hydrocarbon content of motor diesel fuels affects their cetane number and exhaust emissions. The aromatic hydrocarbon and the napthalene content of aviation turbine fuels affects their combustion characteristics and smoke forming tendencies. These properties are included in the aviation turbine fuel Specification D1655. U.S. EPA regulates aromatic content, and California Air Resources Board (CARB) regulates the total aromatics and polynuclear aromatics hydrocarbon contents of motor diesel fuels.
This test method is applicable to materials in the boiling range of the motor diesel fuels and is unaffected by fuel coloration. Aromatics concentration in the range 1 to 75 mass %, and polynuclear aromatic hydrocarbons in the range 0.5 to 50 mass % can be determined by this test method.
The results obtained by this method are statistically more precise than those obtained by Test Method D1319 for diesel fuels and aviation turbine fuels. This test method is also quicker. Results from this test method for total polynuclear aromatic hydrocarbons are also expected to be at least as precise as those of Test Method D2425.
TEST SUMMARY
A small aliquot of the fuel sample is injected onto a packed silica adsorption column and eluted using supercritical carbon dioxide mobile phase. Mono- and poly-nuclear aromatics in the sample are separated from nonaromatics and detected using a flame ionization detector. The detector response to hydrocarbons is recorded throughout the analysis time. The chromatographic areas corresponding to the mono-, polynuclear, and nonaromatic components are determined and the mass percent content of each of these groups is calculated by area normalization.
TEST PRECISION
