[Determination of Vc with phosphomolybdate-blue spectrophotometry].

According as that Vc can reduce phosphomolybdate ammonium quantitatively to blue substance on certain conditions, a new spectrophotometry determinting Vc is proposed in this paper. On the conditions selected in this paper, the maximum absorptive wavelength of phosphomolybdate-blue formed by the reaction of ammonium phosphomolybdate with Vc is at 700.1 nm. It does not form moly-blue (650 nm) when excessive ammonium phosphomolybdate react with trace Vc. The conditions of determination is easy to control. This method can determinate Vc in food, medicine easily and conveniently. The accuracy and the repeatability are satisfactory.