主题：【讨论】USP 281

281  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 pharmacopoeias 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 Pharmacopoeia general chapter. These pharmocopoeias have been undertaken not to make any unilateral change to this harmonized chapter.
此通则的各部分已经与欧洲药典和日本药典的对应部分做了协调。不一致的部分用符号（◆ ◆）来标明。因此，这些药典中协调一致的内容是可以互换的，欧洲药典和/或日本药典的方法可以替代美国药典的通则，用于显示符合性。对于这个协调一致的章节，这些药典已经承诺不进行任何单方变更。

The Residue on Ignition / Sulfated Ash test utilizes 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.
炽灼残渣/硫酸化灰分检测是当根据下面所述的步骤使样品在有硫酸的情况下灼烧后，测量未挥发的残留物质量的方法。该检验通常用用检测一个有机物质中的无机杂质的含量。

Procedure— Ignite a suitable crucible (for example, silica, platinum, quartz, or porcelain) at 600 ± 50  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：取一个适当的坩锅（例如，硅、铂、石英、或者瓷器），在600±50 条件下灼烧30分钟，在干燥器（硅胶或者其他适合的干燥剂）中将该坩锅冷却，并精确称重。精确称取◆1-2克该物质，或者◆在具体的各论中规定的数量，于该坩锅中。

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 600 ± 50 , ◆unless another temperature is specified in the individual monograph, ◆ until the carbon iscompletely 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（通常1mL）硫酸润湿该样品，然后在尽可能低的温度下温和加热至该样品彻底炭化。放凉；然后，◆除非在具体的各论中另有规定◆，以少量（通常1mL）硫酸润湿残渣；温和加热直到白色浓烟不再析出；再于600 ± 50 条件下，◆除非各论中规定其他的温度◆，灼烧，至碳被彻底焚化。确保在此步骤中的任何时间均不得出现火焰。在干燥器（硅胶或其他适当的干燥剂）中放凉该坩锅，精确称重，并计算残渣的百分比。

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 0.5mg or until the percentage of residue complies with the limit in the individual monograph.
除非有其他规定，如果这样得到的残渣数量超过具体的各论中指出的限度，重复此前的以硫酸润湿、加热、灼烧等步骤，灼烧30分钟，直到两次连续残渣称量的重量差不超过0.5mg或者直到残渣的百分比符合具体各论中的要求。

◆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 600 ± 50 .
◆在通风良好的罩子里进行灼烧，但须防止其接触气流，并且在尽可能低的温度进行，以便使碳实现彻底燃烧。如果需要，可以使用马弗炉，并且建议在600 ± 50 的最终灼烧时使用该炉。

Calibration of the muffle furnace may be carried out using an appropriate digital temperature meter and a working thermocouple probe calibrated against a standard thermocouple traceable to the National Institute of Standards and Technology.
进行马弗炉的校准，可以使用一个适当的数字温度表和一个工作热电偶探测器，该探测器须使用能够追索到国立标准和技术研究院（National Institute of Standards and Technology）的标准热电偶进行校准。

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 is ±25  at each position measured. ◆
通过检查炉子内部控制设备点位置的操作温度，证实马弗炉的测量和控制电路的准确性。关于供试品的位置，选择能够反映最终所使用方法的位置。每个测量位置的公差是±25 。◆