| identification test | solubility swells in water to form a transparent to milky viscous colloidal solution. Insoluble in boiling water and ethanol. 0.1% of the sample liquid can be shaken violently to form a layer of foam (this test can make cellulose ether different from sodium carboxymethyl cellulose or sodium alginate or natural colloid). Take 5ml of 0.5% sample solution and add 5ml of 5% copper sulfate solution or aluminum sulfate solution. There should be no precipitation (this test can make cellulose ether different from sodium carboxymethyl cellulose, gelatin, locust bean gum and tragacanth gum). When 1% sample liquid is slowly heated from room temperature to a temperature higher than 35 ℃ under stirring, turbid precipitate can be produced and completely disappeared during cooling. |