Variety doubt

I have a 25 centavos coin from El Salvador, dated 1999, and I don't know if it's N# 9192 or N# 2506, as they both seem equal (appart composition). Could anyone help me to figure wich one I have?

The 9192 is made of stainless steel, the other from nickel-clad steel.
An XRF-test will tell you who is who.

If need a XRF test they should be on the same reference, what collector does have this technology

Geison

If need a XRF test they should be on the same reference, what collector does have this technology

Doesn't matter. Even if they were on the same coin page you would need different year lines for the different compositions and then you're in the same boat.