Ash content of hydroxypropyl methyl cellulose HPMC and its existing form

Hydroxypropyl methyl cellulose (HPMC) industrial quality standards called ash and pharmacopoeia called sulfate, namely burning residue, can simply be understood as the inorganic salt impurities in the product. Mainly by the production process of strong alkali (sodium hydroxide) through the reaction to the final adjustment of pH to neutral salt and raw material original inherent inorganic salt sum.

Method for determination of total ash; A certain amount of samples are burned in a high temperature furnace after carbonization, so that organic materials are oxidized and decomposed, escaping in the form of carbon dioxide, nitrogen oxides and water, while inorganic materials remain in the form of sulfate, phosphate, carbonate, chloride and other inorganic salts and metal oxides, these residues are ash. The total ash content of the sample can be calculated by weighing the residue.

According to the process in the use of different acid and will produce different salt: mainly sodium chloride (by the reaction of chloride ion in chloromethane and sodium hydroxide) and other acid neutralization can produce sodium acetate, sodium sulfide or sodium oxalate.