【CAS】63-68-3 Molecular formula:C5H11NO2S Relative molecular mass: 149.21
Structural formula:
一．Product Property：
Melting point: 276 – 279℃ (deci)
Specific rotation: 23.25℃ (in 2.6N HCl solution)
Water solubility: Soluble
Solubility: Easily soluble in water. The solubility in water at 25℃ is 25g/100ml; at 50℃ it is 39.1g/100ml; at 75℃ it is 54.4g/100ml.
At 100℃, its concentration is 67.2g/100ml. It is insoluble in ethanol and can be dissolved approximately 0.06g in 100g of anhydrous ethanol. It is almost insoluble in acetone and ethanol.
二．Quality Index:
| Parameter | Unit | Specification (Food Grade) |
| Appearance | — | White or light yellow crystalline powder |
| Assay (C₅H₁₁NO₂S) | % (w/w) | ≥ 98.5 |
| Loss on Drying | % (w/w) | ≤ 0.5 |
| Residue on Ignition | % (w/w) | ≤ 0.1 |
| Heavy Metals (as Pb) | mg/kg | ≤ 10 |
| Arsenic (As) | mg/kg | ≤ 2 |
| Iron (Fe) | mg/kg | ≤ 30 |
| Chloride (Cl⁻) | % (w/w) | ≤ 0.2 |
| Sulfate (SO₄²⁻) | % (w/w) | ≤ 0.3 |
| Ammonium Salt (NH₄⁺) | % (w/w) | ≤ 0.05 |
| pH (1% solution) | — | 5.0–7.0 |
| Microbiological Limits | — | Total plate count ≤ 1000 CFU/g; No pathogens |
三．Application scope and Usage：
DL-Methionine (Food-Grade) is a vital sulfur-containing amino acid primarily used as a nutritional supplement in food and animal feed to improve protein balance. In the food industry, it is added to cereals, dairy products, and health foods to enhance nutritional value, especially in vegetarian or low-protein diets. It also serves as a flavor enhancer in processed foods and seasonings due to its umami properties.
四．Package and Storage：
The packaging of this product is 25 kilograms per bucket.
For storage, keep methionine in a cool, dry, well-ventilated warehouse away from direct sunlight, high humidity, and strong oxidizers.
