ASTM-D6406:99(R2020) pdf free download – Standard Test Method for Analysis of Sugar in Vegetable Tanning Materials.
8.4 Munson and Walker Method for Sugar Analvsis.
8.4.1 Measure a 50 mL aliquot by pipet into a 400 niL beaker containing a mixture of 25 mL of the alkaline tarirate solution and 25 mL of the copper sulfate solution and cover the beaker. Heat this mixture to 100°C, as indicated by a thermometer, in exactly 4 mm and continue boiling for exactly 2 mm.
8.4.1.1 Regulate the rate of heating before the determination is started by adjusting the burner or hoplate so that 50 mL of water, 25 rnL of the tartrate solution, and 25 mL of the copper sulfate solution in a 400 mL beaker will he heated to 100°C in exactly 4 mm.
8.4.2 Filter the solution, without dilution, immediately through a tared crucible. Wash the residue thoroughly with hot water, then with alcohol, and finally with ether. Prepare the tared crucibles ahead of time by oven drying and weighing as described in Test Method DM03.
8.4.3 Dry the crucible and contents for 30 mm in the oven. cool in a dessicator, and weigh.
8.5 Deteriti liza 11011 of To 1(11 Sugars:
8.5.1 To a 500 rnL Erlenmeyer flask add 150 rnL aliquot of the clarified (dc-tanned) and deleaded filtrate solution obtained from 8.2.3 and 7.5 mL of concentrated hydrochloric acid. Connect a reflux condenser to the Erlenmeyer flask and boil the mixture under refluxing conditions for exactly 1 h to hydrolyze the sugars. lithe solution foams at the start, which is unusual, add live to ten drops of kerosene to the mixture. Then remove the flask from the heat source, loosely stopper when moderately cool, and allow to stand until ready for reduction, usually overnight.
8.5.2 When ready for reduction, cool the hydrolyzed solution in ice-water for 20 to 30 mm and add two drops of phcnolphthalcin solution as an indicator. Neutralize the cooled solution carefully with a saturated solution of sodium hydroxide. Then add concentrated hydrochloric acid, drop by drop, until the red or pink color of the indicator is just discharged.
8.5.3 After being brought to ambient laboratory
temperature, quantitatively transfer the solution to a 200 mL volumetric flask, diluted to the mark with distilled water, mixed, and filtered until clear. Determine total sugars by the Munson and Walker procedure (8.4) using duplicate 50 mL.
8.5.4 Where the solution of tanning material contains ap
preciable amounts of magnesium salts, carry the hydrolysis out as in 8.5.1. Then cool the solution in ice-water for 20 to 30 mm, add two drops of phcnolphthalcin. neutralize with the saturated solution of sodium hydroxide and add two drops in excess. Without delay, transfer the mixture to a 200 mL volumetric flask, dilute to volume with distilled water, mix, and filter until clear.