ASTM D1839 Standard Test Method for Amyl Nitrate in Diesel Fuels
9. Preparation of Calibration Curve
9.1 Prepare a series of standard samples containing a known amount of amyl nitrate in diesel fuel, covering the range of 0.2 to 2.0 mg of amyl nitrate per gram (Note 3). Weigh 0.5-g portions of these standards, to the nearest 0.1 mg, into the Squibb-type separatory funnels and treat as described in Section 10. Calculate the milligrams of amyl nitrate in each standard by multiplying the weight of the standard taken by the corresponding concentration of amyl nitrate. Construct a calibration curve by plotting absorbance values as the ordinate and corresponding milligrams of amyl nitrate per 50 mL as the abscissa.
NOTE 3 - Experience with the method indicates that different base stocks of diesel fuels do not cause variations in the results. If low results are obtained for a particular fuel, prepare standards using the fuel in question to check the reaction and recoveries.
