Effect of carbonate content and buffer type on calcium phosphate formation in SBF solutions

Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:

A solution containing appreciable amounts of a weak conjugate acid-base pair is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added. A solution of acetic acid and sodium acetate is an example of a buffer that consists of a weak acid and its salt: CH3COOH (aq) + CH3COONa (aq). An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride: NH3 (aq) + NH4Cl...

The phosphate buffer system is a critical biological mechanism for maintaining pH stability in the body. This system operates primarily through two components: sodium dihydrogen phosphate (NaH2PO4), which acts as a weak acid, and sodium hydrogen phosphate (Na2HPO4), which serves as a weak base.
Sodium dihydrogen phosphate does not fully dissociate in neutral or acidic solutions. When a strong base, such as sodium hydroxide (NaOH), is introduced into the solution, sodium dihydrogen phosphate...

The titration of a polyprotic base such as sodium carbonate with a strong acid such as hydrochloric acid results in two equivalence points on the titration curve. At the first equivalence point, the carbonate ions in the base are completely converted to bicarbonate ions. The second equivalence point corresponds to the complete conversion of bicarbonate ions to carbonic acid, which dissociates into carbon dioxide and water. The region before the first equivalence point corresponds to the...

The carbonic acid-bicarbonate buffer system is critical for maintaining the body's pH balance. It operates on the equilibrium:

Buffer solutions do not have an unlimited capacity to keep the pH relatively constant . Instead, the ability of a buffer solution to resist changes in pH relies on the presence of appreciable amounts of its conjugate weak acid-base pair. When enough strong acid or base is added to substantially lower the concentration of either member of the buffer pair, the buffering action within the solution is compromised.
The buffer capacity is the amount of acid or base that can be added to a given volume...