美国药典USP31(921)翻译版(下)VIP专享

Method Ib (Residual Titration) 方法Ib（残留滴定） Principle— See the information given in the section Principle under Method Ia. In the residual titration, excess Reagent is added to the test specimen, sufficient time is allowed for the reaction to reach completion, and the unconsumed Reagent is titrated with a standard solution of water in a solvent such as methanol. The residual titration procedure is applicable generally and avoids the difficulties that may be encountered in the direct titration of substances from which the bound water is released slowly. 原理：见方法Ia 项下原理部分给出的信息。在残留滴定中，额外的试剂被加入到供试样品中，为反应的完成留下了充分的时间，并且将未消耗掉的试剂与水和某种溶剂（例如，甲醇）的标准溶液一起滴定。残留滴定程序通常是可行的，并避免了可能在直接滴定该物质过程中遇到的困难，这些物质中被束缚水分释放得很缓慢。 Apparatus, Reagent, and Test Preparation — Use Method Ia. 仪器、试剂、供试配制液：同方法Ia。 Standardization of Water Solution for Residual Titration— Prepare a Water Solution by diluting 2 mL of water with methanol or other suitable solvent to 1000 mL. Standardize this solution by titrating 25.0 mL with the Reagent, previously standardized as directed under Standardization of the Reagent. Calculate the water content, in mg per mL, of the Water Solution taken by the formula: 用于残留滴定的水溶液的标准化：以甲醇或其他适当溶剂将2mL 水稀释至1000mL，以配制水溶液。使用此前已经按照试剂的标准化项下规定进行过标准化的试剂，对 25mL 此溶液进行滴定，从而对其进行标准化。按照下面的公式，计算此水溶液中的水分含量（单位 mg/mL）： VF/25, in which V is the volume of the Reagent consumed, and F is the water equivalence factor of the Reagent. Determine the water content of the Water Solution weekly, and standardize the Reagent against it period...