ตำรายาของประเทศไทย
Thai Pharmacopoeia
สำนักยาและวัตถุเสพติด กรมวิทยาศาสตร์การแพทย์ กระทรวงสาธารณสุข
Bureau of Drug and Narcotic, Department of Medical Sciences, Ministry of Public Health4.13 DETERMINATION OF INSOLUBLE MATTER
Dissolve the quantity of the sample specified in the monograph in 100 ml of water, heat to boiling unless otherwise directed, in a covered beaker, and warm on a water-bath for 1 hour. Filter the hot solution through a filtering crucible with an asbestos mat or a crucible with a sponge platinum mat or a sintered-glass crucible of fine porosity or a porous porcelain crucible, which has been tared. Wash the beaker and the filter thoroughly with hot water, dry at 105º to constant weight, cool in a desiccator, and weigh.