USP <731>, Loss on Drying
This determines the amount of volatile matter especially water molecules is driven off when heated at specific condition (105° C).
USP <281>, Residue on Ignition (ROI)
ROI is used to determine the percentage of inorganic impurities present by measuring the amount of residual substance not volatilized when ignited in the presence of sulfuric acid.
USP <921>, Karl Fischer Moisture Analysis
The KFR method is based on the quantitative reaction with the presence of trace water with an anhydrous solution of sulfur dioxide and iodine in the buffer that reacts with hydrogen ions.