Determination of trace ascorbic acid by inhibition kinetic spectrophotometry

Objective To establish a new inhibition kinetic spectrophotometric method for the determination of trace ascorbic acid.Methods Ascorbic acid was determined by inhibition kinetic spectrophotometric method,which was based on the inhibition effect of ascorbic acid on the nitrite catalyzed oxidation of xylenol orange by potassium bromate in dilute sulfuric acid medium.Results The linear range of determination was 0.010～0.40?mg/L.The detection limit was 6.8×10~(-6)?g/L.Conclusion The method were simple,high sensitivity and good selectivity.The method was applied successfully to the determination of ascorbic acid in vitamin C tablet and tomato.