Originally Posted by Mac120
Bottle 1 uses sodium hydroxide & acetic acid (to destroy the chelators, so that the iron gets unbound & detectable), bottle 2 Phenantrolin and so Ferrous gluconate can be measured. By adding bottle 3 (Ascorbin acid) = some chelated iron like EDTA can be measured.
Since EDDHA is pretty stable on a very wide PH range, it just seems not too work with those ingredients to destroy such chelators.
So the Billion $$$ questions is:
Is there any hobby grade test kit out there which can handle such chelated stuff?
lol - i stand by my references. There is no way that NaOH and acetic acid (which should neutralize each other, btw) can compare to the oxidizing ability of concentrated, boiling acids in the digestion procedures (as the test methods require). Yes, lewis bases like OH- are better at cleaning organic substances but without using a very concentrated solution, they are just not the same as a digestion.
Furthermore, a digestion is going to chemically oxidize or destroy the chelates. The addition of a strong base like NaOH is probably not destroying the chelators but rather attempting to out compete the chelater for binding sites via a change in equilibrium or something like that. In other words, there's no comparison between the addition of NaOH and an acid digestion in terms of how they liberate the Fe from the chelater.