With the increasing price of fuel, there have been more requests from our clients that are concerned with the Octane and Cetane ratings of their gasoline and diesel. Stored gasoline will lose its Octane rating over time. When time passes during storage the volatile components degrade and form contaminates such as varnish and semi-solid material. Ethanol gasoline can be very unstable and lose its Octane in just one to three months. Cetane numbers can vary in diesels due to increased instability from degradation and potential addition of contaminants and additives.


Octane ratings are a measure of stability. A high octane gasoline rating implies that the fuel is more stable and is based on the pressure at which fuel will spontaneously combust in a variable timed testing engine. Two measurements determine the Octane rating that you see at your neighborhood gas station pump. The Research Octane Number (RON) correlates with automotive spark-ignition engine antiknock performance under mild conditions of operation. The Motor Octane Number (MON) corresponds to fuel anti knock performance for engines operating under heavy load, such as during rapid acceleration of an automobile. The average of the two values, the RON and MON, make up the antiknock index (AKI) which is the octane rating you see on your gas station pump.


Classically FOI Laboratories has provided determination of Octane in gasoline using ASTM methods D2700 (MON) and D2699 (RON). The procedures utilize a large variable timed engine and are fairly expensive, up to $250.00 each per gasoline sample. The time for analysis is also significant, taking a week or more to receive results.  The high price and long analysis time may be a deterrent to business and private individuals who want an Octane check on their stored gasoline. In order to meet this need FOI Laboratories is providing low cost, rapid analysis of RON and MON in gasoline as well as Cetane in diesel by measuring change in the fuels properties of dielectric permeability and electromagnetic induction. The analysis is quick, relatively inexpensive, and provides excellent Octane and Cetane results for your gasoline or diesel.


This procedure is an excellent low cost tool for people who wish to determine Octane or Cetane levels in their fuel. For more information call our customer service at FOI Laboratories, we will be happy to provide you with laboratory testing customized to fit your fuel testing needs. Please contact us at 800-546-4451 or emailing us at info@foilab.com.