This standard specifies a method of determining the purity of more than 95 % (m/m) pure cetane (n-hexade-
cane) and 1-methylnaphthalene used as reference fuels for determining the ignition quality (cetane number)
of diesel fuels (e.g. as specified in DIN 51773). The purity of these reference fuels affects the accuracy of
the determination of the cetane number.