ASTM D2668 Standard Test Method for 2,6-di-tert-Butyl- p-Cresol and 2,6-di-tert-Butyl Phenol in Electrical Insulating Oil by Infrared Absorption
8. Precision and Bias
8.1 Checking Limits of Range (A - Ao) - Determine the highest and lowest values of A - Ao resulting from the three or more scans and subtract one from the other. If the resulting quantity exceeds 0.010, reject the results as excessively variable and repeat the test.
8.2 Repeatability - The difference between two determinations for DBPC and DBP, each obtained from the average of three scans determined manually, 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 value of 0.04 % by only one case in twenty.
8.3 Reproducibility - The difference between two determinations for DBPC and DBP, each obtained from the average of three scans determined manually, obtained by different operators in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the value of 0.04 % by only one case in twenty.
8.4 No statement is made about bias of this test method for measuring ditertiary-butyl paracresol or ditertiary-butyl phenol as it has not been determined.
9. Keywords
9.1 2,6-ditertiary-butyl paracresol; 2,6-ditertiary-butyl phenol; electrical insulating oil; infrared absorption
