Phosphate Content Determination - UV Vis Spectroscopy

This application describes how UV Vis spectroscopy can be used to determine the trace level of phosphate content in water, in the soluble form. For more information about this application, proceed to download the page.

Why is phosphate content measured?

Carbonated soft drinks, especially coke, contain acidulant agents that reduce their pH and assist in beverage preservation for long-term storage. Moreover, phosphate salts are one of the major constituents in natural water, such as ground water which is used in the manufacturing of soft drinks.

Recent studies have shown that hyperphosphatemia (a condition where there is an excess amount of phosphate in the blood) leads to advanced chronic kidney disease (CKD). It is also identified to damage blood vessels and to induce the aging processes. Hence, it is mandatory for manufacturers in food and beverages industry to label and report the exact concentration of phosphate in their products.

How is phosphate content measured?

The measurement is based on Deniges' reaction which involves the addition of ammonium molybdate to a solution of an orthophosphate. The phosphomolybdate produced is partially reduced using ascorbic acid. The intensity of the blue colored complex formed (molybdenum blue) is directly proportional to the concentration of phosphate (PO43-).

This application describes how UV Vis spectroscopy can be used to determine the trace level of phosphate in water at the working concentration of around 2.0 ppm.