Sucrose: (10%) DNS method The DNS method for estimating the concentration of reducing sugars in a sample Reducing sugars contain free carbonyl group, have the property to reduce many of the reagents. 7.4.3.1 Use Glucose (HK) Assay Reagent, Prod. This stock solution is stable for at least 2 weeks at room temperature. This article is cited by 15145 publications. Analar. Dissolve contents per label instructions. Generate a calibration curve to correlate the absorbance to the sucrose concentration. Add to a small amount of cold water in a beaker and make a slurry. Prepare arsenomolybdate reagent in three steps: Dissolve 25 g ammonium molybdate in 400 mL water and add 25 mL concentrated sulfuric acid and mix. The DNSA test can detect concentrations of glucose between 0.5 mM (0.09% glucose w/v) and 40 mM (0.72% glucose w/v). After cooling to room temperature in a cold water bath, record the absorbance with a spectrophotometer at 540nm. Pipette out standard sugar solution in the range of 0 to 3 mL in different test tubes and make up the volume of all test tubes to 3 mL with distilled water concentrations ranging from 0 to 750 mg. Add 1 mL DNS reagent to all the test tubes and mix plug the test tube with cotton or marble and keep the test tube in a boiling water bath for 5 minute. Thamara C. Coutinho, João O. D. Malafatti, Elaine C. Paris, Paulo W. Tardioli, Cristiane S. Farinas. The DNSA reagent base is supplied without sodium hydroxide. 4H 2 O) Add 20cm 3 of 2N NaOH. necessary. Use a good quality starch, e.g. Mix well. Make dilutions of glucose standards; Add 3 ml of DNSA reagent to all the eight test tubes. No. 7.4.4 Cellulase Enzyme Solution (Cellulase) 7.4.4.1 Immediately before use, prepare a solution containing 2-6 units/ml of Cellulase in cold deionized water. Dissolve 3 g sodium arsenate heptahydrate in 25 mL water. 7.4.3 Glucose (HK) Determination Vial. Dilute to a final volume of 100cm 3 with water. Add the DNS reagent and follow the DNS method henceforth. Keep in boiling water bath for 15 minutes. First, take the absorbance (OD) of Blank and make it zero. Mix and heat gently to make a uniform suspension. Then make up to 100 cm3 with boiling water, stirring constantly. (To avoid the loss of liquid due to evaporation, cover the test tube with a piece of paraffin film if a plain test tube is used.) Discussions The DNS method can be applied twice to measure the individual concentrations of a mixture of glucose and sucrose. PREPARATION. The colour of the reagent changes from yellow to orange or red, depending upon the concentration of reducing sugar present. This starch solution does not keep well and should be made up fresh on the required day. 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