Analysis of Fuels
The accidental mixing of fuels is increasingly common and can lead to severe and expensive vehicle damage. In a recent case SGS M-Scan was instructed to compare a sample of fuel received from a vehicle with a sample of pump diesel. Gas Chromatography with Flame Ionisation Detection (GC-FID) was used.
Both the vehicle sample and the reference diesel showed clear evidence of normal n-alkanes over the carbon range C9-26 superimposed upon an unresolved complex mixture of aromatic hydrocarbons, branched alkanes and naphthenes all typical of diesel fuel. However, the fuel sample from the vehicle also showed clear evidence of an additional distribution of components between 1 and 12 minutes on the chromatogram. These were consistent with the presence of petrol that was estimated to represent 9-10% of the fuel sample.
SGS M-Scan has 12 years experience in compliance testing and ‘fingerprinting’ of racing fuels and is the lead laboratory in the FIA Formula 1 fuel testing programme. Samples are tested for compliance to current regulations by several techniques including capillary GC-FID, GC-ECD and GC-MS.
Counterfeit and Adulterated Diesel
Agricultural diesel which has been 'laundered' to remove the identifying dyes and markers can be identified by Liquid Chromatography with Diode Array Detection (LC-DAD) . Impurities left by the 'laundering ' process can assist in identifying the method used.
Biodiesel adulterated by the addition of cooking oil and other products can also be identified