Abstract:  The paper’s aim was to get the optimum wavelength for the determination of xylose content by DNS method. The reaction solution of xylose and DNS regent was scanned from 400～700nm,and the OD values were determined, respectively. The results showed that the max absorption is from 480～490nm, and the line range of the method is 150～600μg/ml (r=0.99997) xylose at 480nm. The result also showed the sensitivity, accuracy, precision are the highest at 480nm, and the recollection rate is more than 99.5%. Therefore, the optimum wavelength is 480nm when the xylose is determined by the DNS method.

Key words:  , DNS method； xylose； optimum wavelength；