ASTM D6428 Test Method for Total Sulfur in Liquid Aromatic Hydrocarbons and Their Derivatives by Oxidative Combustion and Electrochemical Detection
13. Procedure
13.1 Sample sizes ranging from 3 to 40 µL are acceptable. It is advisable that the size of injected sample shall be similar to the size of injected standard.
13.2 Experience dictates the best sample size. Typical sample sizes have been used in the following ranges, (see Table 2).
13.3 Flush the microlitre syringe several times with the unknown sample. Determine the sample size as described in 13.2 and inject it at an even rate as described in 12.4.
14. Calculation
14.1 For analyzers equipped with an automatic calibration, calculate the sulfur content of the sample in parts per million by weight (mg/kg) as follows:
Sulfur,mg/kg = (I - B) x K/V x D
Sulfur,mg/kg = (I - B) x K/M
where:
D = density of sample, g/mL,
K = dilution factor,
V = volume of sample, µL,
M = mass of sample, mg,
I = visual display reading of sample, and
B = average of visual display readings of blank.
14.2 For analyzers not equipped with automatic calibration, calculate the sulfur content of the sample in parts per million by weight (mg/kg) as follows:
Sulfur,mg/kg = I x S x K/V x D
where:
D = density of sample, g/mL,
S = slope of standard curve, mg S/count,
V = volume of sample, µL,
I = detector response, integration counts, and
K = dilution factor (when applicable).
