A minimum of 2 fully fluorinated carbon atoms instead of 1 is NOT broadening the definition. That’s narrowing it.
Think of the definition as a sluice gate. When you allow more things through, you’re opening it wider, therefore broadening the definition. I know it’s counter-intuitive sometimes to think of it like that. Narrowing the definition would be to let fewer things through, thus closing the gate.
Edit:
Reading through the discourse below, I think I see the points made. It might should be reversed.
Allowing more things through, if I understand your analogy correctly in this case, is broadening the exceptions – things not matched by the definition.
But, I’ll bite, let’s dive in. In a Venn diagram, substances with a minimum of 2 fully fluorinated carbon atoms is a subset of substances with a minimum of 1fully fluorinated carbon atoms, yes?
Similarly, M&Ms with only red and green colors is a subset of M&Ms of any color, yes? If a person was to change their personal definition of acceptable M&Ms from any color to only red and/or green, would you call that broadening that definition?
The EPA definition would exclude chemicals like trifluoroethanol, so the EPA’s definition is narrower, not broader.
From a strict organic chemistry perspective, trifluoroethanol contains a perfluorinated methyl group, and methyl is a type of alkyl, therefore it must be considered a PerFluoro Alkyl Substance.
Think of the definition as a sluice gate. When you allow more things through, you’re opening it wider, therefore broadening the definition. I know it’s counter-intuitive sometimes to think of it like that. Narrowing the definition would be to let fewer things through, thus closing the gate.
Edit: Reading through the discourse below, I think I see the points made. It might should be reversed.
Allowing more things through, if I understand your analogy correctly in this case, is broadening the exceptions – things not matched by the definition.
But, I’ll bite, let’s dive in. In a Venn diagram, substances with a minimum of 2 fully fluorinated carbon atoms is a subset of substances with a minimum of 1fully fluorinated carbon atoms, yes? Similarly, M&Ms with only red and green colors is a subset of M&Ms of any color, yes? If a person was to change their personal definition of acceptable M&Ms from any color to only red and/or green, would you call that broadening that definition?
But wouldn’t requireing two fluoridated carbon atoms instead of just one to qualify as PFAS, encompass less chemicals, thus narrowing the definition?
The EPA definition would exclude chemicals like trifluoroethanol, so the EPA’s definition is narrower, not broader.
From a strict organic chemistry perspective, trifluoroethanol contains a perfluorinated methyl group, and methyl is a type of alkyl, therefore it must be considered a PerFluoro Alkyl Substance.