In what way can we enhance the selectivity of EDTA?

Answer 1

I don't understand what you mean by "the selectivity of EDTA"... because EDTA is a abreviation of ethylenediaminetetraacetic acid, a chemical compound, used as a chelating agent... normally found in a lot of industrial cleaners and detergents.

So, if EDTA means something else, you should ask your question again, but tell us what the abreviation stands for.