1. Basic Identification
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Chemical Name: Tetrasodium ethylenediaminetetraacetate
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Synonyms: EDTA tetrasodium salt, Na₄EDTA
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CAS No.: 64-02-8
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Molecular Formula: C₁₀H₁₂N₂O₈Na₄
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Molecular Weight: 380.17 g/mol (anhydrous)
2. Physical & Chemical Properties
| Property | Typical Specification |
|---|---|
| Appearance | White crystalline powder or granules, free of visible impurities |
| Solubility | Freely soluble in water (≥100 g/L at 20°C), clear solution |
| pH (1% aqueous solution) | 10.5–11.5 (alkaline) |
| Bulk Density | 0.6–0.8 g/cm³ (adjustable) |
3. Purity & Active Content
| Parameter | Industrial Grade | High Purity/Reagent Grade |
|---|---|---|
| Assay (on dry basis) | ≥ 99.0% | ≥ 99.5% |
| Chelating Value (as CaCO₃) | ≥ 260 mg/g | ≥ 265 mg/g |
| Water Content | ≤ 2.0% | ≤ 0.5% |
| Ignition Residue (as sulfate) | As per customer requirement | ≤ 0.1% |
4. Impurity Limits
| Impurity Type | Limit (ppm) | Test Method |
|---|---|---|
| Heavy Metals (as Pb) | ≤ 10–20 | ICP-OES/AAS |
| Iron (Fe) | ≤ 10–30 | Colorimetry/ICP |
| Chloride (Cl⁻) | ≤ 50–100 | Ion Chromatography |
| Sulfate (SO₄²⁻) | ≤ 100–200 | Turbidimetry |
| Ammonia Residue | ≤ 50 | Distillation-Titration |
5. Stability & Storage
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Thermal Stability: Stable at room temperature; gradual decomposition above 120°C.
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Light Stability: Insensitive to light, but storage in opaque containers is recommended.
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Storage Conditions: Keep sealed in a cool, dry place. Separate from acids and oxidizers.
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Shelf Life: Typically 2–3 years (unopened).
6. Packaging
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Industrial Grade: 25 kg/bag (paper-plastic composite or woven bag with inner PE liner).
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High-Purity Grade: 1 kg/bottle, 5 kg/drum (HDPE container).
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Customization: Particle size (e.g., 20–100 mesh) or liquid formulations available upon request.
7. Key Application-Related Properties
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Chelating Capacity
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High stability constants with di-/trivalent metal ions (Ca²⁺, Mg²⁺, Fe³⁺), suitable for water treatment, detergents, electroplating, etc.
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Biodegradability
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Poorly biodegradable (persistent in the environment); subject to regulatory restrictions in some regions (e.g., EU REACH).
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Compatibility
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Compatible with most anionic/nonionic surfactants, oxidizers, and alkalis. May precipitate when mixed directly with strong acids or polyvalent metal salts.
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8. Quality Control Standards
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Chinese Standard: GB/T 10718-2023 Tetrasodium EDTA for Industrial Use
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International Standards: USP-NF (United States Pharmacopeia), ACS reagent grade
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Industry-Specific Requirements:
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Cosmetic Grade: Must comply with heavy metal and microbial limits per Cosmetic Safety Technical Standards.
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Food Additive Grade: Must meet GB 1886.XX (China) or FDA 21 CFR §172.135 (USA).
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9. Precautions
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Safety: Dust may irritate respiratory tracts; wear protective masks. Alkaline nature may cause skin irritation; avoid direct contact.
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Environmental Regulations: Use and discharge of EDTA are regulated in some regions (e.g., EU); biodegradable alternatives (e.g., GLDA, MGDA) are recommended for environmentally sensitive applications.
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Testing Methods: Assay is commonly determined by complexometric titration (back-titration with zinc standard solution); impurities require instrumental analysis.
10. Typical Supplier Documentation
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Certificate of Analysis (COA): Includes batch-specific data on assay, impurities, pH, etc.
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Material Safety Data Sheet (MSDS): Covers toxicity, ecological information, and emergency handling.
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Custom Reports: Chelation performance tests (e.g., metal-ion binding capacity) available upon request.