ISO 15647:2004规定了235U浓度小于或等于5质量%、234U和236U浓度在0.001质量%至1.5质量%之间的六氟化铀(UF6)的同位素分析方法。该方法通常用于确定是否符合六氟化铀规格。 如果质谱仪使用法拉第杯，则适用ISO 15647:2004。

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.