Sunday, November 29, 2009

AAS method for Magnesium

Clinical Chemistry Blog Notes # 32 -10

AAS method for Magnesium
Magnesium, as we all know is one of the most important electrolytes in our body. It is an intracellular cat ion. It has a reference range of 0.6-1.5 mg/dl. Maintaining a balance level of magnesium in the body can prevent the occurrence of hypomagnesemia as well as hypermagnesemia. I have also read in “Principles of Anatomy and Physiology” page 1044 that Magnesium is essential for normal neuromuscular activity, synaptic transmission, as well as in myocardial functioning. In addition, secretion of parathyroid hormone depends also on Magnesium.

To explain further the risk that may occur if levels of magnesium in the body are not maintained, I have created a table to present the signs of symptoms of Hypermagnesemia and Hypomagnesemia. (unfortunately, it didnt appear as a table =l )


·Occurs in renal failure or due to increased intake of Mg2+ containing antacids;
·Also occurs in aldosterone deficiency and hypothyroidism.

signs and symptoms
·Hypotension, muscular weakness or paralysis, nausea, vomiting, and altered mental functioning.


·May be due to inadequate intake or excessive loss in urine or feces; also occurs in alcoholism, malnutrition, diabetes mellitus, and diuretic therapy.

signs and symptoms
·weakness, irritability, tenany, delirium, convulsions, confusion, anorexia, nausea, vomiting, paresthesia, and cardiac arrhythmias

Atomic Absorption Spectrophotometry Method for Magnesium
Principle: The absorption of light of free atoms is measured. AAS is based on the “first half” of the excitation process, while atoms absorb light getting their Electrons from the ground state to a higher energy level. This is based on Beer’s Law that states the absorption of light is directly proportional to the number of atoms absorbing it. If the sample is more concentrated, the higher is its absorbance. Same calibration curve or standard addition method can be used in case of AAS. AAS is one of the branches of atomic spectroscopy; its purpose is to determine the concentration of an element in a given sample such as Magnesium, in this case, utilizing the phenomenon that the atoms in the ground state absorb the light of characteristic wavelength passing through an atomic vapor layer of the element. It is quite expensive, but by AAS 70 elements (mainly metals) can be determined using only a very low concentration. As I’ve said, only a very small amount of sample is enough, because the technique itself is high sensitivity.

For the AAS procedure for Magnesium determination, wait for my second blog entry! :)