I am wanting to create an N-free Hoagland's solution and have discovered a recipe that includes sodium ferric ethylenediaminetetraacetate salt $(\ce{C10H12FeN2NaO8}).$ Will the nitrogen in EDTA release into the water and become bioavailable to aquatic plants?
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$\begingroup$ In what form would you consider the nitrogen to be available to plants - nitrates, nitrites, free ammonia, glycine? $\endgroup$– WaylanderMay 4 at 12:22
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$\begingroup$ I will be measuring both nitrate and nitrite in the water, so those, I guess. $\endgroup$– Martin J LambertMay 5 at 11:21
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1$\begingroup$ Then I think you are in the clear. There seems little chance that the nitrogens from EDTA will end up as nitrates or nitrites - see the reference in my answer below. $\endgroup$– WaylanderMay 5 at 12:03
1 Answer
This paper which discusses microbial degradation of EDTA is the most relevant I could find. It identifies the major products of degradation:
Included among these compounds were both isomers of ethylene-diaminediacetic acid (NN-EDDA, and NN'-EDDA), EDMA, NTA (nitrilotriacetic acid), and glycine.
No mention is made of nitrates, nitrites or free ammonia if those are the forms of nitrogen you are principally concerned about.