ISO 15647:2004 specifies a method of isotopic analysis of uranium hexafluoride (UF₆) with ²³⁵U concentrations less than or equal to 5 % by mass and ²³⁴U and ²³⁶U concentration between 0,001 % by mass and 1,5 % by mass. The method is in routine use to determine conformance to UF₆ specifications.

ISO 15647:2004 is applicable if the mass spectrometer uses Faraday cups.