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| Names | |
|---|---|
| Preferred IUPAC name Trisodium 2-hydroxypropane-1,2,3-tricarboxylate | |
| Other names Sodium citrate Trisodium citrate Citrosodine Trisodium salt E331 | |
| Identifiers | |
3D model (JSmol) | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.000.614 |
| E number | E331iii(antioxidants, ...) |
| RTECS number |
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| UNII |
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| Properties | |
| Na3C6H5O7 | |
| Molar mass | 258.06 g/mol (anhydrous), 294.10 g/mol (dihydrate) |
| Appearance | White crystalline powder |
| Density | 1.7 g/cm3 |
| Melting point | > 300 °C (572 °F; 573 K) (hydrates lose water ca. 150 °C) |
| Boiling point | Decomposes |
| Anhydrous form:57 g/100 g H2O (25 °C)[1] Pentahydrate form: 92 g/100 g H2O (25 °C)[2] | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Irritant |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 1548 mg/kg (intraperitoneal, rat)[3] |
| Safety data sheet (SDS) | External MSDS |
| Related compounds | |
Related compounds | Monosodium citrate Disodium citrate Calcium citrate Citric acid |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Trisodium citrate is a chemical compound with themolecular formula Na3C6H5O7. It is sometimes referred to simply as "sodium citrate", though sodium citrate can refer to any of the threesodium salts ofcitric acid. It possesses asaline, mildly tart taste, and is a mildbase.
Sodium citrate is primarily used as afood additive, usually forflavor or as apreservative. ItsE number is E331. Sodium citrate is employed as a flavoring agent in certain varieties ofclub soda. It is common as an ingredient inbratwurst, and is also used in commercialready-to-drink beverages anddrink mixes, contributing a tart flavor. It is found ingelatin mix, ice cream, yogurt, jams, sweets, milk powder, processed cheeses, carbonated beverages, wine, and butter chicken,[4] amongst others.
Sodium citrate can be used as an emulsifying stabilizer when making cheese. It allows the cheese to melt without becoming greasy by stopping the fats from separating.[5] This effect makes cheese particularly suitable as a topping fornachos - coincidentally echoing its chemical formula Na3C6H5O7.[6]
As aconjugate base of a weak acid, citrate can perform as abuffering agent oracidity regulator, resisting changes inpH. It is used to controlacidity in some substances, such asgelatin desserts. It can be found in the milk minicontainers used with coffee machines. The compound is the product ofantacids, such asAlka-Seltzer, when they are dissolved in water.[citation needed] The pH range of a solution of 5 g/100 ml water at 25 °C is 7.5 to 9.0. It is added to many commercially packaged dairy products to control the pH impact of the gastrointestinal system of humans[citation needed], mainly in processed products such as cheese and yogurt, although it also has beneficial effects on the physical gel microstructure.[7]
Sodium citrate is a component inBenedict's qualitative solution, often used in organic analysis to detect the presence of reducing sugars such asglucose. It can also be used to prepare inorganic metal citrates such ascopper citrate.
In 1914, theBelgian doctorAlbert Hustin and theArgentine physician and researcherLuis Agote successfully used sodium citrate as ananticoagulant inblood transfusions, withRichard Lewisohn determining its correct concentration in 1915. It continues to be used in blood-collection tubes and for the preservation ofblood inblood banks. The citrate ionchelates calcium ions in the blood by formingcalcium citrate complexes, disrupting the blood clotting mechanism. Recently, trisodium citrate has also been used as a locking agent in vascath and haemodialysis lines instead of heparin due to its lower risk of systemic anticoagulation.[8]
In 2003, Ööpik et al. showed the use of sodium citrate (0.5 g/kg body weight) improved running performance over 5 km by 30 seconds.[9]
Sodium citrate is used to relieve discomfort in urinary-tract infections, such ascystitis, to reduce the acidosis seen in distalrenal tubular acidosis, and can also be used as an osmoticlaxative. It is a major component of theWHO oral rehydration solution.
It is used as an antacid, especially prior to anaesthesia, forcaesarian section procedures to reduce therisks associated with the aspiration of gastric contents.
Sodium citrate is a particularly effective agent for removal of carbonate scale from boilers without removing them from operation[10] and for cleaning automobile radiators.[11]
