13. Procedure
13.1 Obtain a test specimen using the procedure described in Section 10. The sulfur concentration in the test specimen shall be less than the concentration of the highest standard and greater than the concentration of the lowest standard used in the calibration. If required, a dilution may be performed on either a weight or volume basis.
13.1.1 Gravimetric Dilution (mass/mass) - Record the mass of the test specimen and the total mass of the test specimen and solvent.
13.1.2 Volumetric Dilution (mass/volume) - Record the mass of the test specimen and the total volume of the test specimen and solvent.
13.2 The injection rate shall be consistent with that used in the calibration procedure (See Section 12).
13.3 Measure the response for the test specimen solution using the procedures described in 12.3.
13.4 Determine sulfur concentration in accordance with the manufacturer's instructions.
13.5 Cleaning and Recalibration - Clean any coked or sooted parts per the manufacturer's instructions. After any cleaning or adjustment, assemble and verify operation by analyzing a calibration check standard (see Section 16).
13.6 Density values needed for the calculations are to be obtained using the Test Methods D1298, D4052, or equivalent, at the temperature at which the sample specimen was taken for analysis by this test method.
14. Calculations
14.1
where:
RFS = response factor for sulfur,
Cn = sulfur concentration in mg/kg in the calibration mixture,
An = counts from the detector from calibration mixture,
Cu = sulfur concentration in mg/kg of the sample, and
Au = counts from the detector from the sample.