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Overview


Many chemical reactions are affected by acidity. A solution's acidity must remain constant in order to control a reaction and its rate. In biochemistry, all fluids in organisms have constant pH levels to maintain proper body functions. However natural processes such as gas absorption from the atmosphere, impurification, decomposition, precipitation, advanced dissolution, and fermentation, change pH levels in fluids. These alterations are conrolled by buffers, which control pH levels in fluids.

Buffers have the property of maintaining a particular pH in a varied pH range. They do this by mixing a weak acid with its conjugate base or a weak base with its conjugate acid. Buffers are most prevalent in organisms to maintain body function. This is essential to many living organisms because their bodies produce acids amd bases, which must be neutralized in a variety of ways. Like most organisms, the majority of this "neutralization" occurs through and in the blood stream.


Historyexternal image Charles_Gerhardt.jpg

Throughout history, buffers were used to induce particular pH levels within solutions. No one invented buffers because it is a natural process. An example would be the use of bicarbonate in the blood and cell fluids.

Since buffering is a natural process that can be damaged, people developed buffers to help people with acidosis amongst other diseases that affect acidity. The first synthetic buffer was used and developed by the Chinese in pre 1000 B.C. They used saturated charcoal to treat severe heart burn and poisoning.[1] Later in history, chemists used buffers in drugs to enhance their effect. An external image activated-charcoal-powder-200X200.jpgexample of this is Aspirin (developed in 1853 by Charles Frederic Gerhardt), which prevents the flow of prostaglandins (pain nerves) in a particular pH range. Since the human blood is not acidic enough for aspirin, aspirin had a weaker effect. For this reason, Bayer, a pharmaceutical company, added MgO molecules to aspirin to increase the pH level in the blood to enhance aspirin’s effect in 1908. In 1928, Jim Howe used Chinese ideals to develop the buffer Tums to cure his wife’s indigestion.[2] The use of this buffer was to help neutralize acid in the stomach to relieve pressure, discomfort, and indigestion. Throughout history, the main purposes of synthetic buffers were to enhance the effects of drugs, or to neutralize/intensify acidity levels within fluids.

Acids and the Body

There are several body functions that increase the acidity of body fluids. However, there are several body processes which can remove acids and bases from the body instead of the conventional blood buffing solution. For example, the kidneys remove bicarbonate from the body, while the lungs remove carbon dioxide.

Kidneys

The kidneys also affect acidity in the blood. The kidneys produce about 250g of bicarbonate per day.[3] They do this by reacting the carbonic acid and water in the blood to form bicarbonate and hydronium. The kidney’s production of bicarbonate makes the blood more basic because it equalizes the aciexternal image wegener.gifdic carbonic acid.[4]

Lungs

The lungs inhale air and exhale carbon dioxide amongst other gas particles. They inhale air by contracting the diaphragm to decrease the pressure in the lungs, and the pressure indifference causes the air in the surroundings to surge back into the lungs. This process is known as breathing. The lungs exhale carbon dioxide because the carbon dioxide is stuck to the red blood cells in the Alveoli in the lungs. The oxygen and carbon dioxide switch places so the body can remove toxins from the body while providing cells with oxygen.[5]

This process affects the acidity level in the blood. This is because it removes carbon dioxide which is needed to produce carbonic acid, hydronium, and bicarbonate. Since the lungs remove a base ingredient needed for acids, the pH level of the body is affected by the lungs.


Natural vs Synthetic

Buffers are all around us. They are in us, we eat them, and they are necessary for our survival. However, while all buffers do the same thing, there are two different types: natural and synthetic.

Natural Buffers

Natural buffers are acid-base reactions that are made through natural processes. The body has two natural buffers: bicarbonate (base) and carbonic acid (acid). Both bicarbonate and carbonic acid are produced by each other. This is because bicarbonate reacts with hydronium to form carbonic acid and water, while carbonic acid reacts with water to form bicarbonate and hydronium. The process keeps repeating until eqilibrium is reached. Since the acids balance the bases, it keeps the acidity of the blood near neutral.
external image hydronium.jpg

Synthetic Buffers

Synthetic buffers are quite different from natural buffers. Synthetic buffers are created in labs and often contain the basic salt, sodium bicarbonate. These buffers are created for people who suffer from acidosis, a disease in which the body fluids are too acidic or too basic.[6] Also, many drugs are lined with buffers to make the blood more acidic or more basic to enhance a drug’s effect. It is important to notice the both synthetic buffers and natural buffers have the same physical properties and that many of the natural buffers can be made in laboratories.

Chemical Explanation

The most important chemical reaction in maintaining the acid-base reaction in blood is the carbonic acid-bicarbonate buffer. Here's an illustration of it:

Picture_1.jpg

We are interested in the change in the pH of the blood; therefore, we want an expression for the concentration of H+ in terms of an equilibrium constant and the concentrations of the other species in the reaction.

Here's another picture which illustrates picture 1 in a clearer representation:

Picture_2.jpg

The acid-base reaction on the left shows the formation of carbonic acid from bicarbonate and hydronium. This reaction shows equilibrium because the bicarbonate (base) is used to create carbonic acid (acid) and vice versa. Since one makes the other, the formation of the acids and bases will reach equilibrium, thus allowing the blood to maintain a stable pH range of 6.8-7.8 pH.[7] The right side of the equation is not an acid-base reaction. However it shows that the roots of carbonic acid and bicarbonate are water and carbon dioxide and they are needed to maintain acidity.

The second part of the equation implies that equilibrium will never be reached. This is becaue the levels of water and carbon dioxide differ within the body at all times. This implies that acid-base reaction will never reach equilibrium because its base reaction will never be constant. This is further implied that the body will never be able to reach a stable pH level. However, the equation implies that when there is more carbon dioxide in the blood, the will eventaully be more bicarbonate in the blood. This is because in order to create bicarbonate, carbon dioxide must dissolve in water to create carbonic acid and water, and they react to form bicarbonate and hydronium. Since water has a greater pressence in the blood than hydronium, and hydronium is rapidly used by the cells and the digestive system.[8] Therefore, this reaction will always produce slightly more bicarbonate than carbonic acid because prevalent water in the body will excell the reaction.


Buffers in Everyday Life

Acidosisexternal image acidosis.png

Acidosis is a disease in which the body has too much acid. This causes the blood to become slightly acidic. As a result, the acidity of the blood kills white blood cells and significantly weakens the immune system. This causes people to easily attract fungi infections, virus infections, bacteria infections, and mold infections.
From a scientific perspective, this means that the body has too much carbonic acid. To lower the carbonic acid, a person must drink water because carbonic acid reacts with water to form bicarbonate which will lower carbonic acid levels.[9]

Heartburnexternal image Cause-of-Heartburn.jpg

Heartburn is a burning sensation in the esophagus when stomach acid (HCl) is backed up into the esophagus/throat. This is extremely common among all people because the esophagus does not close completely sometimes, allowing the acid to reflux.
Minor heartburn cases are treated with a buffer to neutralize the acids in the esophagus. Tums are commonly used because they help neutralize acids in the esophagus quickly and efficiently by making turning the hydrochloric acid into salt water.

Works Cited


  1. ^
    "aspirins - definition of aspirins by the Free Online Dictionary, Thesaurus and Encyclopedia.." Dictionary, Encyclopedia and Thesaurus - The Free Dictionary. N.p., n.d. web. 4 June 2010. <http://www.thefreedictionary.com/aspirins>.
  2. ^ "The Howes of Oxford and St Louis." Haine Family Website. N.p., n.d. Web. 4 June 2010. <http://haine.org.uk/howe.htm>.
  3. ^ "Chemical of the Week -- Biological Buffers." Science is Fun in the Lab of Shakhashiri. N.p., n.d. Web. 4 June 2010. <http://www.scifun.org/chemweek/BioBuff/BioBuffers.html>.
  4. ^ process, the kidneys is a relatively slow, and may take too. "pH Buffers in the Blood." Department of Chemistry. N.p., n.d. Web. 4 June 2010. <http://www.chemistry.wustl.edu
  5. ^
    Kozak, Charles. "Mucin Buffers." Gastric Mucin. Minneapolis Medical School, n.d. Web. 10 June 2004. <lib.bioinfo.pl/meid:118764>.
  6. ^ "Acidosis - Causes and Natural Treatment." Top water ionizers direct from USA importer. Free DVD on alkaline water. Ionizers from exclusive US importer.. N.p., n.d. Web. 4 June 2010. <http://www.ionizers.org/acidosis.html>.
  7. ^ "Acid-Alkaline pH chemical balance." INDEX - Earthtym.net: Health-4-All, a foundation for health.. N.p., n.d. Web. 4 June 2010. <http://www.earthtym.net/ph-intro.htm>.
  8. ^ "Buffer systems maintian a constant pH in blood ." Chem 104. N.p., n.d. Web. 10 June 2004. <www.brynmawr.edu/Acads/Chem/Chem104lc/buffers.html>.
  9. ^
    Quinn, Antonia. "Acidosis." EMedicine. N.p., n.d. Web. 10 June 2004. <emedicine.medscape.com/article/768268-overview>.