Abstract: It has been already found that the ascorbic acid could reduce the phosphomolybdic acid salt into molybdenum blues quantitatively. Hence the concentration level of vitamin in the food could thus be determinde by the spectrometry. In this paper. the effect of some factors on the developing reaction had been studied in detail. The results showed that the reaction rate of vitamin and molybdenum was rather fast, the environmentel effect was small and the O D value of theis system was stable in acid medium. Beer’s law was obeyed in the range of 8-28ug/ml for ascorbic acid. In the range, the calibrated equation was Y=0. 189292+3686.31X(mol/L),the linear correlation coefficient R=0.99826,the indirect molar absorbing coefficient 3.68631 × 10~3 and the maximum absorption wavelength was 705nm and the coefficient of recovery was in the range of 97.50%-98.63%.This method was simple quick and accurate.

Key words: Spectrometry Ascorbic Acid Molybdenum blue method