Why not titrate Fe directly (permanganate), without separation?
My apologies. I dont know what I was thinking
it is not Mg it is Mn. So permanganate will not work because of the Mn.
Any P in a metal sample being dissolved in acid is going to be reduced by nascent hydrogen into phosphine, which other than affecting your analysis is also really toxic.
Why not EDX?
We can only use traditional methods.
So if the P in the metal was solubilized with HNO3 ¿Can I safetly asume that in the precipitate left there is only Si?
And I should mention that the current state of the analysis is the dissolved metal and a solution that I think contains: Mn, Fe and I guess that PH3. And the presipitate of the dissolved metal currently is on a filter paper and I'm guessing that it only contains Si.
PS.
If a nice mod could change my mistake in the title Mg to Mn and also in the first post as I cannot see how to do it