M-EDTA features
1. EDTA complexing properties with a wide range, with almost all of the metal ions to form a stable chelate.
Advantageous: offers the possibility of measuring a wide range of elements (superior acid, precipitation).
The downside: Easy interference between the various components – selectivity.
2. EDTA and M-EDTA complex formation than the vast majority of 1:1.
3 chelate most charged, it can dissolve in water, rapid response CASNo. :6381-92-6.
Toxicity Protection: This product toxicity. The oral LD50 for rats 2000mg/kg. See other toxic and content protection “ethylene diamine tetra-acetic acid.”
Packing: cartons or sacks lined with double plastic bag, 80kg.
Properties: white crystalline powder. Low toxicity, soluble in water, aqueous solution of pH 5% of the value of 4-6. Acidic. Insoluble in alcohol.
Mainly used as a complexing agent.
The equilibrium dissociation EDTA
In aqueous solution, 2 H + transferred to the carboxyl group N, forming a bipolar ion:
EDTA H4Y said common due to its solubility in water and an acid in a small, commonly used for the disodium salt: Na2H2Y · 2H2O, also abbreviated as EDTA.
When the high acidity of the solution, the two carboxyl groups may be longer accept H +, formed H6Y2 +, the equivalent of a six-membered acid, has six dissociation constants:
Ka1 = 10-0.9; Ka2 = 10-1.6; Ka3 = 10-2.1; Ka4 = 10-2.8; Ka5 = 10-6.2; Ka6 = 10-10.3.
Seven forms:
H6Y2 +, H5Y +, H4Y, H3Y-, H2Y2-, HY3-, Y4-
When pH <1, mainly H6Y2 + form;
When pH> 11, the main presence in Y4-form – complex ion.