ASTM D2887 Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
13. Report
13.1 Report the temperature to the nearest 0.5°C (1°F) at 1 % intervals between 1 and 99 % and at the IBP (0.5 %) and the FBP (99.5 %).
NOTE 8 - If a plot of the boiling point distribution curve is desired, use graph paper with uniform subdivisions and use either retention time or temperature as the horizontal axis. The vertical axis will represent the boiling range distribution (0 to 100 %). Plot each boiling temperature against its corresponding normalized percent. Draw a smooth curve connecting the points.
14. Precision and Bias
14.1 Precision - The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows:
14.1.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values by only one case in twenty (see Table 4).
14.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only one case in twenty (see Table 5).
NOTE 9 - This precision estimate is based on the analysis of nine samples by 19 laboratories using both packed and open tubular columns. The range of results found in the round robin are listed in Table 6.
14.2 Bias - The procedure in Test Method D2887 for determining the boiling range distribution of petroleum fractions by gas chromatography has no bias because the boiling range distribution can only be defined in terms of a test method.
14.2.1 A rigorous, theoretical definition of the boiling range distribution of petroleum fractions is not possible due to the complexity of the mixture as well as the unquantifiable interactions among the components (for example, azeotropic behavior). Any other means used to define the distribution would require the use of a physical process, such as a conventional distillation or gas chromatographic characterization. This would therefore result in a method-dependent definition and would not constitute a true value from which bias can be calculated.
15. Keywords
15.1 boiling range distribution; correlation; distillation; gas chromatography; petroleum; petroleum fractions; petroleum products; simulated distillation
