Trisodium citrate
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2008-06-21T15:59:41Z
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{{Chembox new
| Name = Sodium citrate
| ImageFile = Sodium citrate.png
| ImageSize = 200px
| ImageName = Sodium citrate
| IUPACName = trisodium 2-hydroxypropane-1,2,3-tricarboxylate
| OtherNames = citrosodine; trisodium citrate; trisodium salt
| Section1 = {{Chembox Identifiers
| SMILES = [Na+].[Na+].[Na+]. O=C([O-])CC(O)(CC(=O)[O-])C([O-])=O
| CASNo = 68-04-2
}}
| Section2 = {{Chembox Properties
| Density = 1.7 g/cm³, solid (approximate)
| Solubility = 72 g/100 ml
| MeltingPt = 150 °C
| BoilingPt = Decomposes
| pKa =
| pKb =
| MolarMass = 294.1 g/mol
| Formula = Na<sub>3</sub>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>
| Appearance = White crystalline powder
}}
| Section3 = {{Chembox Structure
| CrystalStruct =
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/S3386.htm External MSDS]
| MainHazards = Irritant
}}
| Section8 = {{Chembox Related
| Function = compounds
| OtherFunctn = [[calcium citrate]], [[citric acid]]}}
}}
'''Trisodium citrate''' has the chemical formula of Na<sub>3</sub>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>. It is sometimes referred to simply as ''[[sodium citrate]]'', though sodium citrate can refer to any of the three sodium salts of [[citric acid]]. It possesses a saline, mildly tart, flavor. For this reason, citrates of certain [[alkali metal|alkaline]] and [[alkaline earth metal]]s (e.g. sodium and calcium citrates) are commonly known as ''sour salt'' (occasionally citric acid is erroneously termed ''sour salt'').
==Applications==
===Food===
Sodium citrate is chiefly used as a [[food additive]], usually for [[flavor]] or as a [[preservative]]. Sodium citrate is employed as a flavoring agent in certain varieties of [[club soda]].
Sodium citrate is common as an ingredient in lemon-lime and citrus [[soft drink]]s such as [[Ting (soft drink)|Ting]] and [[Chinotto]], contributing to their tart tastes, and can also be found in such energy drinks as [[Rockstar (drink)|Rockstar]] and [[Red Bull]].
===Buffer===
As a [[conjugate base]] of a weak acid, citrate can perform as a [[buffering agent]], resisting changes in [[pH]]. Sodium citrate is used to control [[acid]]ity in some substances, such as [[gelatin dessert]]s. It can be found in the mini milk containers used with coffee machines. The compound is the product of antacids such as Alka-Seltzer when they are dissolved in water.
===Medical uses===
In [[1914]], the [[Belgium|Belgian]] doctor [[Albert Hustin]] and the [[Argentina|Argentine]] physician and researcher [[Luis Agote]] successfully used sodium citrate as an [[anticoagulant]] in [[blood transfusion]]s. It continues to be used today in blood collection tubes and for the preservation of [[blood]] in [[blood bank]]s. The citrate ion [[chelation|chelates]] calcium ions in the blood, disrupting the blood clotting mechanism.
Recently, Oopvik, et al. showed that use of sodium citrate (approx. 37 grams) improved running performance over 5 km by 30 seconds.<ref>{{cite journal | title = Effects of sodium citrate ingestion before exercise on endurance performance in well trained college runners | author = V Oöpik, I Saaremets, L Medijainen, K Karelson, T Janson, S Timpmann | journal = Br J Sports Med | year = 2003 | volume = 37 | pages = 485–489 | url = http://bjsm.bmj.com/cgi/content/abstract/37/6/485 | doi = 10.1136/bjsm.37.6.485 | pmid = 14665584}}</ref>
Sodium citrate is used to relieve discomfort in urinary tract infections such as [[cystitis]], to reduce the acidosis seen in distal [[renal tubular acidosis]], and can also be used as an osmotic [[laxative]].
It is used as an antacid, especially prior to anaesthesia for caesarian section to reduce the [[Mendelson's syndrome|risks]] associated with the aspiration of gastric contents.
==See also==
* [[Sodium citrate]]
* [[Citric acid]]
==References==
<div class="references-small"><references /></div>
[[Category:Food acidity regulators]]
[[Category:Citrates]]
[[Category:Sodium compounds]]
[[Category:Chelating agents]]
[[ar:سترات صوديوم]]
[[de:Natriumcitrat]]
[[it:Citrato di sodio]]
[[hu:Nátrium-citrát]]
[[pt:Citrato de sódio]]
[[ru:Цитрат натрия]]