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色层分析法

又译色谱法。利用不同化学物质在气流或液流中被固定物质吸附的速率不同而将它们分离的方法,1903年首度由俄国植物学家茨维特提出,他用於分离有色的化合物(由此得名)。但他的工作被忽视多年,直到1930年代才又获重视,色层分析法基於对惰性液流或气流所载各种组分的吸附力有所不同,因此对它们的阻滞或保留时间也不同,从而具有使它们分离的能力。进行色层分析时,使含有未知混合物的气体或液体(流动相)在一种表面积很大的吸附剂(固定相)的上面或内部通过。混合物的各组分则被固定相分离,然後分别进行监定。最原始的技术是将有机溶液由顶端加入粉末状氧化铝柱,并用一种有机溶剂来淋洗该柱,以分离植物色素混合物。现代采用的方法则有纸色层分析法、薄层色层分析法、液相色层分析法(包括高效液相色层分析法)和气相色层分析法。其中一些还停留在实验阶段,但一些(特别是高效液相色层分析法)已应用到工业上。他们需要不同的方法来侦测或鉴定分离出来的成分,包括比色法、分光光度学、质谱测定法,以及萤光、电离电势或热传导等测量法。1952年的诺贝尔化学奖得主马丁(与辛格共获)发展了液相色层分析法和纸色层分析法,并在诺贝尔领奖典礼上演讲时宣布研发了气相色层分析法。

chromatography

Method first described in 1903 by Mikhail S. Tsvet for separating mixed chemical substances. Tsvet's neglected work, rediscovered in the 1930s, uses the different affinities of substances in a solution in a mobile phase (a moving stream of gas or liquid) for adsorbtion onto a stationary phase (a fine-grained solid, a sheet of filtering material, or a thin film of a liquid on a solid surface). Choices of materials for these phases allow enormous versatility for separating substances including biological fluids (e.g., amino acids, steroids, carbohydrates, pigments), chemical mixtures, and forensic samples. In the original technique, an organic solvent flowed through a column of powdered alumina (see aluminum), sodium carbonate, or even powdered sugar to separate mixed plant pigments. Among current adaptations are paper chromatography (PC), thin-layer chromatography (TLC), liquid chromatography (LC, including high-performance liquid chromatography, or HPLC), and gas chromatography (GC). Some remain laboratory techniques, but some (especially HPLC) can be used on an industrial scale. They require different methods for detecting and identifying the separated components, including colorimetry, spectrophotometry, mass spectrometry, and measurement of fluorescence, ionization potential, or thermal conductivity. A. J. P. Martin shared a 1952 Nobel Prize for developing LC and PC, and in his Nobel lecture announced the development (with his cowinner R. L. M. Synge and other colleagues) of GC.