In times of rocketing gasoline prices, ethanol - mainly derived from the fermentation of sugar cane (in Brazil) and corn (in the USA and Canada) - is a promising renewable high-octane vehicle fuel
A major drawback to the use of ethanol is the contamination with inorganic salt ions such as chloride, nitrate and sulphate.
These ions can affect the engine performance because precipitating salts clog filters and fuel injector nozzles.
Furthermore, these ions enhance corrosion in the vehicle components in contact with the fuel.
Hence there is an urgent need for standards defining quality specifications and test methods.
While the analysis of sulfate is specified in a number of ASTM standards, until recently, the ASTM D 4806-06b standard - the specification for denatured fuel ethanol - provided no guidelines for total and potential sulfate.
Recognising the need for validated methods for quality control, ASTM balloted and approved a sulphate specification for fuel ethanol stipulating a maximum level of sulfate in ethanol of four parts per million (ppm).
In this paper a convenient direct injection suppressed ion chromatographic method for determining chloride and sulphate in denaturated ethanol samples is presented.
The method complies with ASTM D 4806-06c.
