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用巴歇尔等(W.Battscher,W.Schmidts)提出的对比电导法可以快速测定二氧化碳含量。这一方法特别适用于有机物元素分析的目的。分析方法如下:对用来吸收二氧化碳的氢氧化钠溶液与一个不变的标准溶液进行电导度测定和对比。这一比例与二氧化碳的含量不呈线性关系。但如电路选择得当,样品电池和对比溶液保持在相等温度下,线性关系是可以达到的。氢氧化钠溶液的浓度不能太高,否则就难以确定二氧化碳的含量,因为在这一情况下,吸收不可能完善。不过,这一困难可以通过加入一些糖酶或者氨基化合物(例如氨基乙醇)缓冲的办法来克服。经过这样改进以后,准确度大大提高。这一方法可以用来测定有机物中的含碳量。即使是小于1毫克以下的样品,结果比一般通用的分析方法更为准确。
The comparative conductivity method proposed by W. Barttscher, W. Schmidts allows rapid determination of carbon dioxide content. This method is particularly suitable for the purpose of organic elemental analysis. Analytical methods are as follows: Conductivity determination and comparison of the sodium hydroxide solution used to absorb carbon dioxide with a constant standard solution. This ratio is not linear with the carbon dioxide content. However, if the circuit is chosen properly, the sample cell and the comparative solution are kept at the same temperature and the linear relationship is achievable. The concentration of sodium hydroxide solution can not be too high, otherwise it is difficult to determine the content of carbon dioxide, because in this case, the absorption is not perfect. However, this difficulty can be overcome by adding a buffer of carbohydrase or amino compound (eg, aminoethanol). After this improvement, the accuracy is greatly improved. This method can be used to determine the carbon content of organic matter. Even samples smaller than 1 milligram have more accurate results than commonly used analytical methods.