ASTM D2472 Standard Specification for Sulfur Hexafluoride
6. Test Methods
6.1 Water Content - Test Method D2029.

6.2 Hydrolyzable Fluorides - Determine the acidity, expressed as HF, in accordance with Test Method D2284.

6.3 Air - Determine the amount of noncondensable gases, expressed as nitrogen, by gas chromatographic analysis in accordance with Test Method D2685.

6.4 Carbon Tetrafluoride - Determine the amount of carbon tetraflluoride by gas chromatographic analysis in accordance with Test Method D2685.

6.5 Assay - Assay shall be by difference, after impurity content has been determined.

7. Keywords
7.1 electrical insulating gas; sulfur hexafluoride