I think, you may use Ascorbic Acid method.

Using:

1. ICP techniqe

or

Concentration in Saxulat or in dry heater

or depended on add stander solution to all sample such as

add 1ml of 1ppm of stander of P like phosphor salts

Standard Stock Solution

Dilute 1, 2, 3, 4, and 5 mL Stock Solution to100-mL numbered flaks by adding distilled water, and then bring to volume. These solutions contain 0.5, 1.0, 1.5, 2.0, and 2.5 ppm P, respectively.

The molybdate reaction should be preceded by a digestion with persulfate. Both the molybdate reaction and ICP have limited sensitivity.

Use the molybdenum blue procedure (reduction of the phosphomolybdic acid complex) as listed by APHA (American Public Health Association) 'Water and Wastewater Standard Methods'. Just need a UV-Vis Spectrophotometer at 650 nm or 1100 nm.

Interesting discussion on estimating total P in water streams.Keeping aside detailed fractionation schemes of P in water or waste waters, a least three sources of P in water need to be included /recognized in total P estimation.They are water soluble orthophosphate P, soluble organic P and particulate P. Prior digestion of the sample is desired to include the organic and particulate P in water. Without digestion of sample,one may estimate only the soluble P using the colorimetric method as suggested by colleagues.ICP may estimate P from all the three sources,watersoluble, particulate and soluble organic without recognizing the source.So probably one can avoid digestion of sample when one uses ICP-OES technique for estimating total P. On the other hand one may underestimate the total P in water witout digestion of sample and use of the colorimetric procedure.The relative contribution of the orthophosphate, particulate and organic of P may vary depending on source of water and possible contaminants while water is flowing through stream.

Dear All,

Thank you for your kind response and valuable suggestions.

Best Regards,

Nimesha.