Since the presence of contaminants can lead to operational problems, biofuels are required to meet specific quality control criteria.  In the case of biodiesel the American Society for Testing and Material (ASTM) and European Standards Organization (EN) have developed methods (ASTM D6751 or EN 14214) by  which pure biodiesel (B100) can be tested. Physical, chromatographic and spectroscopic methods are used to apply the standard. 

FuelPro is developed specifically to address the trace metal analysis component of these quality standards.  At this time, the methods only require measurement of sodium, potassium, calcium, magnesium, phosphorous and sulfur. Controlling the content of these metals in biofuels has been shown to be important for the following reasons:
Sodium and potassium – sodium and potassium hydroxides are utilized as catalysts and in the production of biodiesel and should be removed through the production process.  Failure to control the level of these metals in the final product can result in the formation of deposits in the fuel injection system and also poisoning of emission control after-treatment systems. 

Magnesium and calcium - magnesium and calcium are used as absorbents in the production of biodiesel and should be removed through the production process.  These residual metals can form deposits in fuel injection system components and poison emission control after-treatment systems.

Phosphorus – Phosphorus has been shown to damage the ability of after-treatment systems to reduce exhaust emissions as intended.  The influence of phosphorus is cumulative; and as a result, very low levels of contamination over the significant amount of fuel consumed by an engine may lead to unexpected deterioration of the after treatment system.

Sulfur – Sulfur levels in fuel are regulated by various governmental agencies to assure compatibility with emission standard requirements.  In the United States there are currently three sulfur grades: S5000, S500, and S15, for both D1 and D2 petroleum diesel fuel. Biodiesel blends may not exceed the applicable maximum sulfur levels as defined for petroleum diesel.