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Sodium is an essential element for all animal life (including human) and for some plant species. In animals, sodium ions are necessary for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions. Sodium is the chief cation in extracellular compartment of animal body.
Sodium plays a vital role not only in human body but also in various food types. Sodium chloride is the principal source of sodium in the diet, and is used as seasoning and preservative, such as for pickling and jerky; most of it comes from processed foods.
The sodium content in various foods can be analyzed by using Flame Photometry. Flame photometry also called flame atomic emission spectrometry is a branch of atomic spectroscopy in which the species examined in the spectrometer are in the form of atoms.
The samples used for analysis are junk foods which have become a common trend among all generations. A total of 15 junk foods were processed and analyzed for estimating the sodium content in them by Flame Photometry.
Based on the analysis the samples were categorized into low, moderate and high sodium containing foods. The analysis helps in creating awareness among all the generations to reduce the sodium intake in order to prevent problems like hypertension, hyponatremia, hypernatremia and associated medical complications in their future.

Reference Id: PHARMATUTOR-ART-1412

is a chemical element with the symbol Na (from Latin: natrium) and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals such as feldspars, sodalite and rock salt. Many salts of sodium are highly soluble in water and are thus present in significant quantities in the Earth's bodies of water, most abundantly in the oceans as sodium chloride.

Sodium - silvery-white alkali metal

DENSITY: 0.971 g/cm 3

Many sodium compounds are useful, such as sodium hydroxide (lye) for soap making, and sodium chloride for use as a deicing agent and a nutrient. Sodium is an essential element for all animals and some plants. In animals, sodium ions are used against potassium ions to build up charges on cell membranes, allowing transmission of nerve impulses when the charge is dissipated; it is therefore classified as a dietary inorganic macro-mineral. The free metal does not occur in nature, but instead must be prepared from its compounds; it was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide

Characteristics of Sodium:
Sodium at standard temperature and pressure is a soft metal that can be readily cut with a knife and is a good conductor of electricity. Freshly exposed, sodium has a bright, silvery luster that rapidly tarnishes, forming a white coating of sodium hydroxide and sodium carbonate. These properties change at elevated pressures: at 1.5 Mbar, the color changes to black, then to red transparent at 1.9 Mbar, and finally clear transparent at 3 Mbar. All of these allotropes are insulators and electrides.


When sodium or its compounds are introduced into a flame, they turn it yellow, because the excited 3s electrons of sodium emit a photon when they fall from 3p to 3s; the wavelength of this photon corresponds to the D line at 589.3 nm (Earnshaw, A, et al 1997)

A positive flame test for sodium has a bright yellow color

Sodium is generally less reactive than potassium and more reactive than lithium. Like all the alkali metals, it reacts exothermically with water, to the point that sufficiently large pieces melt to a sphere and may explode; this reaction produces caustic sodium hydroxide and flammable hydrogen gas (Emsley, John 2001) When burned in dry air, it mainly forms sodium peroxide as well as some sodium oxide, in moist air, sodium hydroxide results. Sodium metal is highly reducing, with the reduction of sodium ions requiring −2.71 volts but potassium and lithium have even more negative potentials. Hence, the extraction of sodium metal from its compounds (such as with sodium chloride) uses a significant amount of energy.

Sodium compounds are of immense commercial importance, being particularly central to industries producing glass, paper, soap, and textiles. The sodium compounds that are the most important are common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCO3), caustic soda (NaOH), sodium nitrate (NaNO3), di- and tri-sodium phosphates, sodium thiosulfate (Na2S2O3·5H2O), and borax (Na2B4O7·10H2O). In its compounds, sodium is usually ionically bonded to water and anions, and is viewed as a hard Lewis acid.

Like the other alkali metals, sodium dissolves in ammonia and some amines to give deeply coloured solutions; evaporation of these solutions leaves a shiny film of metallic sodium. The solutions contain the coordination complex (Na(NH3)6)+, whose positive charge is counterbalanced by electrons as anions; cryptands permit the isolation of these complexes as crystalline solids. Cryptands, like crown ethers and other ionophores, have a high affinity for the sodium ion; derivatives of the alkalide Na- are obtainable by the addition of cryptands to solutions of sodium in ammonia via disproportionation.

Salt has been an important commodity in human activities, as shown by the English word salary, which derives from salarium, the wafers of salt sometimes given to Roman soldiers along with their other wages. In medieval Europe, a compound of sodium with the Latin name of sodanum was used as a headache remedy. The name sodium is thought to originate from the Arabic suda, meaning headache, as the headache-alleviating properties of sodium carbonate or soda were well known in early times. The chemical abbreviation for sodium was first published by Jöns Jakob Berzelius in his system of atomic symbols, and is a contraction of the element's new Latin name natrium, which refers to the Egyptian natron, a natural mineral salt primarily made of hydrated sodium carbonate. Natron historically had several important industrial and household uses, later eclipsed by other sodium compounds. Although sodium, sometimes called soda, had long been recognised in compounds, the metal itself was not isolated until 1807 by Sir Humphry Davy through the electrolysis of sodium hydroxide.

Sodium imparts an intense yellow color to flames. As early as 1860, Kirchhoff and Bunsen noted the high sensitivity of a sodium flame test.

Commercial production:
Enjoying rather specialized applications, only about 100,000 tonnes of metallic sodium are produced annually. Metallic sodium was first produced commercially in 1855 by carbothermal reduction of sodium carbonate at 1100 °C, in what is known as the Deville process:

Na2CO3 + 2 C → 2 Na + 3 CO

A related process based on the reduction of sodium hydroxide was developed in 1886.

Sodium is now produced commercially through the electrolysis of molten sodium chloride, based on a process patented in 1924. This is done in a Downs Cell in which the NaCl is mixed with calcium chloride to lower the melting point below 700 °C. As calcium is less electropositive than sodium, no calcium will be formed at the anode. This method is less expensive than the previous Castner process of electrolyzing sodium hydroxide.

Reagent-grade sodium in tonne quantities sold for about US$3.30/kg in 2009; lower purity metal sells for considerably less. The market for sodium is volatile due to the difficulty in its storage and shipping; it must be stored under a dry inert gas atmosphere or anhydrous mineral oil to prevent the formation of a surface layer of sodium oxide or sodium superoxide. These oxides can react violently in the presence of organic materials. Sodium will also burn violently when heated in air. Smaller quantities of sodium cost far more, in the range of US$165/kg; the high cost is partially due to the expense of shipping hazardous material.

Sodium consumption:
Sodium chloride is the principal source of sodium in the diet, and is used as seasoning and preservative, such as for pickling and jerky; most of it comes from processed foods. The DRI for sodium is 2.3 grams per day, but on average people in the United States consume 3.4 grams per day, the minimum amount that promotes hypertension (Grobbee, D. E. 2004); this in turn causes 7.6 million premature deaths worldwide.

About 90% of Americans eat more sodium than is recommended for a healthy diet. Too much sodium increases a person's risk for high blood pressure. High blood pressure often leads to heart disease and stroke. More than 800,000 people die each year from heart disease, stroke and other vascular diseases, costing the nation $273 billion health care dollars in 2010. Most of the sodium we eat comes from processed foods and foods prepared in restaurants.

Sodium is already part of processed foods and cannot be removed. However, manufacturers and restaurants can produce foods with less sodium.

Sodium in biology:
Sodium is an essential element for all animal life (including human) and for some plant species. Sodium ions are necessary in small amounts for some types of plants, but sodium as a nutrient is more generally needed in larger amounts by animals, due to their use of it for generation of nervous impulses and finer regulation of fluid balance.

In animals, sodium ions (often referred to as just "sodium") are necessary for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions. Sodium is the chief cation in extracellular compartment of animal body. A normal serum sodium level is 135 - 145 mEq/liter (mEq/L).

Sodium cations are important in neuron (brain and nerve) function, and in influencing osmotic balance between cells and the interstitial fluid, with their distribution mediated in all animals (but not in all plants) by the so-called Na+/K+-ATPase pump. In the nerve cells, this sodium-potassium flux generates the electrical potential that aids the conduction of nerve impulses. This electrical potential gradient, created by the "sodium-potassium pump," helps generate muscle contractions and regulates the heartbeat.

Sodium is an essential nutrient that regulates blood volume, blood pressure, osmotic equilibrium and pH; the minimum physiological requirement for sodium is 500 milligrams per day.



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