1. Rationale
In section 7.10, the method prescriptively requires the use of a 0.1 N K2Cr2O7 solution to standardize the 0.1N sodium thiosulfate solution (i.e., . . . Standardize against 0.1 N K2Cr2O7 solution, using any appropriate technique, such as the one indicated in 4500-C1 B. Standardize at intervals frequent enough to detect changes of 0.0005 in normality.). An issue was raised by a lab indicating that the 0.1 N K2Cr2O7 solution cannot be used in their lab due to industrial hygiene (IH) / safety reasons and would like to use a different reagent (e.g., KIO3) to perform the standardization. In checking the 4500-Cl B procedure that is cited in D3703, it does allow an option to standardize the 0.1N Na2S2O3 solution with 0.1 N KIO3. As such, proposed revisions are identified to provide labs with the flexibility to use 0.1 N KIO3 as an alternative to using a 0.1 N K2Cr2O7 solution to standardize the 0.1N Na2S2O3 solution.
Keywords
aviation fuels; diesel fuel; gasoline; hydroperoxide; hydroperoxide number; turbine fuel;
Citing ASTM Standards
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