FUEL 13 |
| Ethanol used as a blending agent in gasoline can be contaminated with chloride and sulfate that form plugging deposits and cause corrosion in automobile engines. If sulfate and chloride concentrations exceed the limits defined in ASTM Specification D 4806, then the ethanol may be rejected as unacceptable for use in automotive spark-ignition engine fuel. ASTM International has proposed that a new ion chromatography (IC) method be adopted to measure this critical product specification for ethanol intended for automotive spark-ignition engine fuel use. There are several sample preparation methods available to determine anions in various organic solvents such as ethanol. The method presented here addresses drawbacks of previous methods such as rapid loss in sulfate peak area/height with time, which can result in the underreporting of sulfate data. In this new method, the AS Autosampler performs a direct inject on a TAC-ULP1 anion concentrator, installed in place of the injection loop, and then washes off the ethanol. The elimination of the ethanol allows the use of electrolytic suppression in the recycle mode for the highest level of convenience. The method also exhibits good sulfate stability even when 20 mg/L of sulfate is spiked into gasoline denatured ethanol. Sulfate and chloride are separated on an IonPac® AS22 column. This improved method for determining sulfate and chloride in ethanol allows the analyst to easily determine if their ethanol meets ASTM Specification D 4806. This method is also easier to operate and more rugged than previous methods. |
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Characterization of Fossil and BioFuels: Challenges and Progress
8:25 AM-12:10 PM, Sunday, August 19, 2007 Boston Park Plaza -- Arlington Rm, Oral
Division of Fuel Chemistry |