ASTM D5986 for Oxygenates, Benzene, Toluene and Aromatics in Finished Gasoline
ASTM D5986 Standard Test Method for Determination of Oxygenates, Benzene, Toluene, C8-C12 Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography/Fourier Transform Infrared Spectroscopy
10. Sample Analysis Procedure
10.1 Add 1.0 mL of internal standard into a 10.0 mL volumetric flask or vial and record the mass (Ws). Add 9.0 mL of gasoline sample to the flask or vial, and record the mass (Wg). The sample/internal standard solution is then mixed 30 s on a vortex mixer and analyzed by GC/FTIR according to the instrument manufacturer’s directions using the same conditions as for calibrations.
11. Quality Control Reference Material
11.1 After the calibration has been completed, prepare the quality control reference material outlined in Table 8. Analyze the reference material as described in the sample preparation procedure below. The individual aromatic and total aromatics values obtained must agree within more or less 5 % relative of the values in the prepared reference material (for example, benzene 1.0 more or less 0.05). If the individual values are outside the specified range verify calibration and instrument parameters, accuracy of the preparation of quality control reference material, and so forth. Do NOT analyze samples without meeting the quality control specifications.
11.1.1 If samples containing oxygenated fuel additives such as ethanol, methyl-t-butylether (MTBE) are also analyzed in addition to conventional oxygenates free gasolines, then several quality control reference materials must be prepared containing the major oxygenated additives at levels found in gasoline samples.
11.2 Analyze the quality control reference materials before every batch of samples. Bracket the samples with the reference material. If the reference material does not meet the specifications in 11.1, the samples analyzed immediately preceding the reference material are considered suspect and should be rerun.
