When determining TP of water using Phosphorus Molybdenum Blue Method, ascorbic acid solution was unstable, can only be kept for several weeks.

The latter was investigated by the phosphomolybdate blue method, high_resolution TEM and XPS spectrum.

Objective: to set up a method for the determination of phosphorous in food samples by ammonium molybdate spectrophotometry after pretreated with the microwave digestion technique.