Ions maybe classified as cations – positively charged or anions – negatively charged.  These ions produce certain colors in flame photometry which could help in their identification in unknown solutions.   Some examples of cations are: sodium (Na), magnesium (Mg), potassium (K) and calcium (Ca); while examples of anions are: chloride (Cl), HCO3 (bicarbonate), inorganic phosphorus (I.P.)

Each of these ions has specific functions in the body.  Their main functions are the following:

1. Sodium – active role in osmotic balance.
2. Magnesium – transmission of nerve impulses
3. Potassium – cardiac contraction
4. Calcium – bone growth
5. Chloride – passive role in osmotic balance
6.  Bicarbonate – maintenance of acid base balance.
7. norganic phosphorous – takes part in the biochemical process of food metabolism.

In flame photometry, these are the colors produced by some of them:

1. Sodium – yellow
2. Magnesium – blue
3. Potassium – violet
4. Calcium – red-orange
5. Chloride – this will depend upon the type of reagent it reacted with.
6. Bicarbonate – utilizes another method of determination like blood analysis.
7. Inorganic phosphorous – makes use of a preferred  method of determination – colorimetry

For chloride determination, the color produced with its reaction with different reagents is measured through a spectrophotometer.  The spectrophotometer is a machine that measures the concentration of an unknown solution by measuring its color intensity – the more colored solution is more concentrated.   The ending solution may be colored light yellow, pink or violet.

For bicarbonate determination and inorganic phosphorus, these are performed too making use of the same machine but with different reagents.   

Necessary precautions should be observed in the performance of the above mentioned procedures:

1. Contamination of unknown and reagents should be avoided to ensure reliability of results.
2. Use de-ionized water in diluting your solutions.  This is to avoid adding ions into the unknown solution.

The simplest method for the determination of electrolyte is the flame method.  A Bunsen burner and a wire loop could be used to heat the solution in the flame and observe for the color emitted in the flame by the ions.