Process effectiveness is measured as oil depletion relative to internal chemical markers.
Conserved internal chemical markers, such as C30 17a(H), 21b(H)-hopane (a biomarker), are identified and measured by GC/MS.
The concentration of these compounds in the degraded samples relative to the concentration in the original product is used to estimate oil depletion as a measure of process effectiveness.
Other internal markers, such as the C4 alkyl phenanthrenes/anthracenes, can be substituted for hopane in diesel range products.