The Colorimetric E stimation of Inorganic P hosphate

1. The Colorimetric Estimation of Inorganic Phosphate

2. Introduction A phosphate, an inorganic chemical, is a salt of phosphoric acid It consists of one central phosphorus atom surrounded by four oxygen atoms in a tetrahedral arrangement. The phosphate ion carries a negative three formal charge

3. phosphorusis found as a free phosphate ion in solution and is called inorganic phosphate, to distinguish it from phosphates bound in various phosphate esters. Inorganic phosphate is generally denoted Pi

4. Phosphate are most commonly found in the form of adenosine phosphates, (AMP, ADP and ATP) and in DNA and RNA

5. Principle The measurement of inorganic phosphate must be one of the comments determinations carried out in a biochemistry lab. It is certainly surprising how frequently such a measurement is required, and the production of a standard curve is a useful exercise for checking the validity of Beer’s Law.

6. Inorganic phosphate reacts with ammonium molybdate in an acid solution to form phosphomolybdic acid. A reducing agent such as metol is added which reduces the molybdenum to give a blue colour but does not affect the uncombined molybdic acid.

7. Acid solu Pi + ammonium molybdatephosphomolybdic acid phosphomolybdic acid + metol(reducing agent) blue colour Metol not combine with excess of molybdic acid

8. Method

9. Mix, incubate at RT for 10 min. And then read at 880nm.

10. Calculation C1 X V1 = C2 X V2

11. Introduction Inorganic phosphate react with ammonium molybdate in an acid solution to form phosphomolybdic acid. A reducing agent such as metol is added which reduces the molybdenum to give a blue colour but does not affect the uncombined.