ASTM D6560 Test Method for Determination of Asphaltenes (Heptane Insolubles)
ASTM D6560 Standard Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum Products
13. Report
13.1 Report the following information:
13.1.1 The heptane insoluble asphaltene content of values less than 1.00 % m/m, to the nearest 0.05 % m/m, by Test Method D6560.

13.1.2 The heptane insoluble asphaltene content of values of 1.0 % m/m and greater, to the nearest 0.1 % m/m, by Test Method D6560.

14. Precision and Bias
14.1 Precision - The precision values were determined in an interlaboratory program, using benzene as solvent, in 1956. A second interlaboratory program, using toluene as solvent, was carried out in 1975 to confirm the precision. No data from the 1956 evaluation program can be found.

NOTE 5 - A recent (1998) interlaboratory program in France on four samples with asphaltene contents in the range from 0.50 to 22.0 % m/m resulted in estimated precision values very similar to those given in 14.2 and 14.3, except for the reproducibility at very low levels (<2.0 % m/m), which was significantly worse.

14.2 Repeatability - The difference between two successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the normal and correct operation of the test method, exceed the value below in only one case in twenty.
r = 0.1A
where A is the average result, in % m/m.

14.3 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on nominally identical test material would, in the normal and correct operation of the test method, exceed the value below in only one case in twenty.
R = 0.2A
where A is the average result, in % m/m.

14.4 Bias - Since heptane insoluble asphaltenes are defined by this test method, no bias can be assigned. The term asphaltenes may be associated with other similar procedures using alkanes as precipitating agents other than heptane. In general, lighter alkanes will give higher results and heavier alkanes will give lower results than heptane, but no consistent ratio can be assigned.

15. Keywords
15.1 asphaltenes; bitumen; crude petroleum; diesel fuel; gas oil; heptane insoluble residues; lubricating oil; residual fuel oils