Tetrasodium ethylenediaminetetraacetate (tetrasodium EDTA) is the tetrasodium salt of ethylenediaminetetraacetic acid (EDTA). It is a white, crystalline solid that is highly soluble in water and functions primarily as a chelating agent, binding metal ions such as calcium, magnesium, iron, and copper.
Chemical identity
- IUPAC name: tetrasodium 2,2′,2′′,2′′′-(ethane‑1,2‑diylbis(azanetriyl))tetraacetate
- Formula: C₁₀H₁₂N₂Na₄O₈
- Molar mass: 380.20 g mol⁻¹
- CAS number: 60‑31‑1 (for the anhydrous tetrasodium salt)
Physical properties
- Appearance: white to off‑white powder
- Solubility: > 100 g L⁻¹ in water at 20 °C; practically insoluble in most organic solvents
- pH of a 1 % aqueous solution: approx. 10.5–11.0
Functions and applications
| Sector | Primary uses |
|---|---|
| Food industry | Designated food additive E 385; used to sequester metal ions that could catalyze oxidation, thereby prolonging shelf life of processed foods and beverages. |
| Cosmetics and personal care | Added to shampoos, lotions, and skin‑care products to improve product stability, promote foaming, and mitigate metal‑induced discoloration. |
| Pharmaceuticals | Employed in formulations to enhance solubility of drugs, as a stabilizer in injectable solutions, and in some topical preparations. |
| Industrial water treatment | Utilized in boiler water, cooling‑tower water, and detergents to prevent scale formation and inhibit metal‑catalyzed degradation. |
| Laboratory reagents | Common chelating agent in biochemistry and molecular biology for metal‑ion removal, enzymatic assays, and as a component of buffer systems (e.g., in DNA extraction kits). |
Safety and regulatory information
- Toxicology: Acute oral toxicity in rodents is low (LD₅₀ ≈ 3 g kg⁻¹). The compound is generally regarded as having low acute toxicity for humans, though ingestion of large quantities may cause gastrointestinal irritation. |
- Handling: Standard laboratory personal protective equipment (gloves, goggles) is recommended. Dust inhalation may irritate the respiratory tract. |
- Environmental impact: Because it forms stable complexes with metal ions, tetrasodium EDTA can increase the mobility of trace metals in aquatic systems. Regulatory agencies monitor its discharge in wastewater, and some jurisdictions have set limits on its concentration in effluents. |
- Regulatory status: Recognized as safe for use in food (E 385) and cosmetics within established concentration limits by agencies such as the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). |
Production
Tetrasodium EDTA is produced by neutralizing aqueous solutions of EDTA with sodium hydroxide, followed by crystallization and drying of the resulting sodium salt.
Chemical behavior
In aqueous solution, the tetrasodium salt dissociates to release the EDTA⁴⁻ anion, which exhibits high affinity for divalent and trivalent metal cations. The stability constants (log K) for complex formation are generally in the range of 14–20, depending on the metal ion and solution conditions.
References
- International Union of Pure and Applied Chemistry (IUPAC). Compendium of Chemical Terminology (Gold Book).
- Food and Agriculture Organization/World Health Organization. Codex General Standard for Food Additives (E 385).
- European Chemicals Agency. Registration Dossier for Tetrasodium EDTA (EC Number 212-350-9).
This entry presents established, verifiable information about tetrasodium EDTA and does not include speculative content.
