USP281炽灼残渣.doc

USP281炽灼残渣
RESIDUE ON IGNITION
炽灼残渣
Portions of this general chapter have been harmonized with the corresponding texts of the European Pharmacopoeia and the Japanese Pharmacopoeia. The portions that are not harmonized are marked with symbols (）。 The harmonized texts of these pharmacopeias are therefore interchangeable, and the methods of the European Pharmacopoeia and/or the Japanese Pharmacopoeia may be used for demonstration of compliance instead of the present United States Pharmacopeia general chapter. These
pharmacopeias have undertaken not to make any unilateral change to this harmonized chapter.
本章的部分地方已经与EP和JP进行了统一,没有统一的部分用标注，统一的部分可以相互通用,EP和JP中的方法可以代替目前的USP的方法。本药典不会对已经统一的地方做出单方面的修改。
The Residue on Ignition/Sulfated Ash test uses a procedure to measure the amount of residual substance not volatilized from a sample when the sample is ignited in the presence of sulfuric acid according to the procedure described below。 This test is usually used for determining the content of inorganic impurities in an organic substance。
用下面描述的方法检测在硫酸存在时对样品灼烧后的不易挥发的残留物质的质量，主要用于检测有机物质中的无机杂质。
PROCEDURE：Ignite a suitable crucible (for example， silica， platinum， quartz， or porcelain） at 60050℃ for 30 minutes, cool the crucible in a desiccator （silica gel or other suitable desiccant）, and weigh it accurately. Weigh accurately ¨1 to 2 g of the substance， or¨the amount specified in the individual monograph, in the crucible.
步骤：选合适的坩埚（如二氧化硅，铂，石英或者陶瓷坩埚)在60050℃下炽灼30分钟，在干燥器（硅胶或者其他合适的干燥剂）中冷却，精确称量.精确称量¨1—2g样品，¨或者专论中规定的量,将物质放入坩埚中。
Moisten the sample with a small amount （usually 1 mL） of sulfuric acid, then heat gently at a temperature as low as practicable until the sample is thoroughly charred. Cool; then， ¨unless otherwise directed in the individual monograph，¨ moisten the residue with a small amount （usually 1 mL） of sulfuric acid； heat gently until white fumes are no longer evolved； and ignite at 60050℃, ¨unless another temperature is specified in the individual monograph，¨ until the residue is completely incinerated.
Ensure that flames are not produced at any time during the procedure. Cool the crucible in a desiccator (silica gel or other suitable desiccant)， weigh accurately， and calculate the percentage of residue.
用少量硫酸（通常1ml）润湿样品，然后用尽可能低的温度对样品缓慢加热直至样品完全碳化，冷却,¨除非专论中特别规定，用少量硫酸（通常1ml）润湿残留物，缓慢加热直至不再生成白烟,¨除非专论中规定了另外的温度,一般在60050℃下灼烧直至残渣完全烧成灰烬。确保整个操作过程不出现火焰，在干燥器（硅胶或者其他合适的干燥剂）中冷却，精确称量，并计算残渣百分含量.
Unless otherwise specified， if the amount of the residue so obtained exceeds the limit specified in the individual monograph, repeat the moistening with sulfuric acid, heating and igniting as before, using a 30—minute ignition period, until two consecutive weighings of the residue do not differ by more than 0。5 mg or until the percentage of residue complies with the limit in the individual monograph。
除非另有规定，如果残渣的量超过了规定值，重复上述加硫酸润湿，加热以及炽灼等步骤，炽灼30分钟，直至连续两次残渣的重量差异不大于0.5mg或者直至残渣的百分含量符合专论中的规定限度.
¨Conduct the ignition in a well—ventilated hood， but protected from air currents, and at as low a temperature as is possible to effect the complete combustion of the carbon。 A muffle furnace may be used, if desired， and its use is recommended for the final ignition at 60050℃.
¨在通风良好的通风橱内进行炽灼实验，但是要防止气流的影响，在尽可能低的温度下实验碳的完全燃烧，如果需要的话,可以使用马弗炉，并且适合最后炽灼的温度为60050℃。
Calibration of the muffle furnace may be carried out using an appropriate digital temperature meter and a working thermocouple probe calibrated against a standard thermos—couple traceable to the National Institute of Standards and Technology。
马弗炉的校验可以使用一个合适的电子温度计和一个工作热电偶探头,这个探头已经按照美国国家标准和技术委员会的标准进行了校正。
Verify the accuracy of the measuring and controlling circuitry of the muffle furnace by checking the positions in the furnace at the control set point temperature of intended use. Select positions that reflect the eventual method of use with respect to location of the specimen under test。 The tolerance is25℃at each position measured。¨
通过核查马弗炉内控制点温度的位置,确认马弗炉的测量和控制电路的准确性。根据正在测试的样品的定位，选择可以反映最终方法的位置点。每个测试位置的允许误差是25℃¨。