ASTM D4905-99 (2020) pdf free.Standard Practice for Preparation of Solution of Solid, Pasty and PowderedVegetable Tannin Extracts.
Empty the sample onto a sheet of clean, glazed paper (orsuitable clean, smooth foil material), roughly crush any largelumps，and quickly mix and quarter the whole. From eachquarter，take a small representative portion,quickly crush,transfer to a small, glass stoppered weighing bottle, and take tothe balance. Without delay,transfer the analytical specimen toa tared container of suitable size and weigh to the nearest 0.1mg. Each sample shall be handled individually, and all operations carried out as quickly as possible up to this point,and allother precautions taken to minimize changes in moisturecontent.
Where the extract has a moisture content such that it cannot be ground, weigh the sample, broken orcut，into small pieces and bring to approximate equilibrium with the laboratory atmosphere by drying for severalhours at a temperature not exceeding 60°C.Allow the sampleto remain exposed to the air in the laboratory until theapproximate equilibrium has been attained. Weigh the partiallydried sample again . Calculate the original moisturecontent of the extract as in Test Method D6403，paragraph9.3.3,except that the residual moisture in the airdried material shall be determined as in the Procedure section of TestMethod D4903 instead of as in Test Method D6403, paragraph9.3.1.
Treat the air-dried sample,prepared as above,as inparagraph 7.1, above. In such cases, calculate the results of theanalysis to the basis of the original moisture before drying. Pour approximately 200 mL of distilled water, at 95°C,into a 1-L volumetric flask and place the container with thespecimen in a funnel resting in the neck of the flask. Adddistilled water, at 95°C, to the extract, filling the container. Stirthe contents of the container well and allow to stand for a fewmoments，so that any undissolved particles may settle to thebottom of the container. Decant the supernatant liquid into theflask, add more of the hot, distilled water to the contents of thecontainer, stirred and decanted, and repeat the process until thesoluble portion of the specimen has been completely dissolvedand the whole of it washed into the flask. Mix the contents ofthe flask by swirling.Add sufficient distilled water, at 96°C, tobring the volume to approximately 900 mL and again mix thesolution by swirling. The full operation of dissolving anddecanting, etc., shall be carried out as quickly as possible, andat no time during the operation shall the temperature of thesolution fall below 80°C. If necessary,apply heat to keep thesolution above 80°℃.ASTM D4905 pdf download.