Ammonium sulfate for biochemistry
| Formula | H8N2O4S |
| Chemical formula | ( NH4)2SO4 |
| Density | 1.77g/cm3 |
| Molar mass | 132.14 g/mol |
| Bulk density | ~ 960 kg/m3 |
| CAS number | 7783-20-2 |
| HS Code | 31022100 |
| EC number | 231-984-1 |
| Storage | Without limitation |
| SDS | available |
| RTECS | BS4500000 |
| Odour | odourless |
| Form | solid |
| Color | colorless |
| p H value | 5.0 -6.0 (20g/l 20 °C) |
| Solubility in water | 754 g/l (20 °C) |
| Solubility in ethanol | insoluble |
| Boiling point | decomposition |
| Thermal decomposition | 280 °C |
| Assay | 99.0 – 100.5 | % | |
| Description | Conforms | ||
| Identification | Conforms | ||
| Solubility | Conforms | ||
| Limit of insoluble matter | ≤ | 0.005 | % |
| p H | 4.5 – 6.0 | ||
| Chloride | ≤ | 0.005 | 3/00% |
| Nitrate | ≤ | 0.005 | % |
| Iron | ≤ | 0.005 | % |
| Phosphate | ≤ | 0.005 | % |
| Arsenic | ≤ | 0.0001 | % |
| Calcium | ≤ | 0.001 | % |
| Cadmium | ≤ | 0.001 | % |
| Copper | ≤ | 0.001 | % |
| Zinc | ≤ | 0.001 | % |
| Lead | ≤ | 0.001 | % |
| Residue on ignition | ≤ | 0.01 | % |
Ammonium sulfate ((NH₄)₂SO₄) is an inorganic salt widely used in biochemistry and molecular biology for protein purification by precipitation. It is a white crystalline solid, highly soluble in water, and works by reducing protein solubility (“salting out”) based on ionic strength.
🏭⚗️ Production
Ammonium sulfate is industrially produced by reacting ammonia with sulfuric acid. It is available commercially as a white powder and is commonly prepared as a saturated aqueous solution to add gradually during protein precipitation procedures.
🔬 Properties
Ammonium sulfate has a high solubility in water (about 70.6 g per 100 mL at 0 °C), and dissociates into ammonium (NH₄⁺) and sulfate (SO₄²⁻) ions. It increases ionic strength of solutions and promotes protein aggregation by reducing hydration shells around proteins. The process is reversible, allowing proteins to be redissolved after precipitation.
🧪 Applications
- Protein purification: Used for fractional precipitation to selectively precipitate proteins based on their solubility differences.
- Enzyme studies: Helps concentrate enzymes while maintaining activity.
- Biochemistry research: Commonly used in crystallization, storage, and stabilization of proteins.
- Industrial use: Applied in fertilizer production and food industry as a food additive.
