(Equivalent Test Methods: IP 156, ISO 3837, DIN 51791, JIS K 2536, and AFNOR M07-024)
EXPLANATION
This test method is intended for use with full boiling range products. It determines hydrocarbon types in the range of 5 to 99 volume % aromatics, 0.3 to 55 volume % olefins, and 1 to 95 volume % saturates in petroleum fractions that distill below 315° C.
TEST SUMMARY
A small amount of sample is introduced into a special glass adsorption column packed with activated silica gel. A small layer of silica gel contains a mixture of fluorescent dyes. When all of the sample has been adsorbed on the gel, alcohol is added to desorb the sample down the column. The hydrocarbons are separated according to their affinities into three types. The fluorescent dyes also react selectively with the hydrocarbon types, and make the boundary zones visible under ultraviolet light. The volume percentage of each hydrocarbon type is calculated from the length of each zone in the column.
TEST PRECISION
The precision statement has been determined with unleaded fuels that do not contain oxygenates. It may or may not apply to other types of gasolines. See the repeatability and reproducibility in the following tables.
Where X = the volume % of olefins.
The bias of this test method has not been determined.