美国药典USP31-NF26色谱《621》.doc

621 CHROMATOGRAPHY色谱法 INTRODUCTION简介 This chapter defines the terms and procedures used in chromatography and provides general information. Specific requirements for chromatographic procedures for drug substances and dosage forms, including adsorbent and developing solvents, are given in the individual monographs.此章节定义了色谱法中用到的术语和环节，并提供了通用信息对于原料药和成药的色谱环节的具体规定，涉及吸附剂和展开溶剂，在具体各论中给出Chromatography is defined as a procedure by which solutes are separated by a dynamic differential migration process in a system consisting of two or more phases, one of which moves continuously in a given direction and in which the individual substances exhibit different mobilities by reason of differences in adsorption, partition, solubility, vapor pressure, molecular size, or ionic charge density. The individual substances thus separated can be identified or determined by analytical procedures.色谱法是应用溶质在两相或多相系统中的差速迁移来进行分离的技术，其中一相持续地向特定方向移动，而由于物质在吸附性、分派、溶解性、气体压力、分子大小、或离子电荷密度上的差别，会显示出不同的移动性。

由此分开的这些单个物质可以通过度析过程鉴别或测定The general chromatographic technique requires that a solute undergo distribution between two phases, one of them fixed (stationary phase), the other moving (mobile phase). It is the mobile phase that transfers the solute through the medium until it eventually emerges separated from other solutes that are eluted earlier or later. Generally, the solute is transported through the separation medium by means of a flowing stream of a liquid or a gaseous solvent known as the “eluant.” The stationary phase may act through adsorption, as in the case of adsorbents such as activated alumina and silica gel, or it may act by dissolving the solute, thus partitioning the latter between the stationary and mobile phases. In the latter process, a liquid coated onto an inert support, or chemically bonded onto silica gel, or directly onto the wall of a fused silica capillary, serves as the stationary phase. Partitioning is the predominant mechanism of separation in gas–liquid chromatography, paper chromatography, in forms of column chromatography and in thin-layer chromatography designated as liquid-liquid chromatography. In practice, separations frequently result from a combination of adsorption and partitioning effects. Other separation principles include ion exchange, ion-pair formation, size exclusion, hydrophobic interaction, and chiral recognition.常规色谱措施规定溶质在两相之间的分派，一种是固定的（固定相），另一种则在移动（移动相）。

流动相的作用是穿过介质转移溶质，直至其最后与其她不同步间洗脱出来的溶质分开一般，该溶质由被称为“洗脱剂”的某种液体或气态溶剂的流动输送着穿过度离介质该固定相可以通过吸附发挥作用，例如活性氧化铝和硅胶之类的吸附剂，或者其可以通过溶解溶质并由此在固定相与流动相之间分派溶质来起作用在背面这个过程中，涂在惰性载体上、或用化学措施键合在硅胶上、或直接在涂布石英毛细管壁上的某种液体作为固定相分派作用是气液色谱法、纸色谱法、多种柱色谱法和薄层色谱法称为液-液色谱法中的重要分离机制在实际操作中，分离常常是吸附与分派联合伙用的成果其她分离原理涉及离子互换、离子对构造、空间排阻、疏水性互相作用、手性辨认The types of chromatography useful in qualitative and quantitative analysis that are employed in the USP procedures are column, gas, paper, thin-layer, (including high-performance thin-layer chromatography), and pressurized liquid chromatography (commonly called high-pressure or high-performance liquid chromatography). Paper and thin-layer chromatography are ordinarily more useful for purposes of identification, because of their convenience and simplicity. Column chromatography offers a wider choice of stationary phases and is useful for the separation of individual compounds, in quantity, from mixtures. Modern high-performance thin-layer chromatography, gas chromatography, and pressurized liquid chromatography require more elaborate apparatus but usually provide high resolution and identify and quantitate very small amounts of material.在USP程序中使用的定性和定量分析中可以使用的色谱法类型是柱、气相、薄层（涉及高效薄层色谱法）、加压液相色谱法（一般称为高压或高效液相色谱法）。

由于以便、简朴，纸和薄层色谱法一般在鉴别用途中更加有效柱色谱法对固定相提供了更广泛的选择，并且可用于从混合物中大量分离单个化合物现代高效薄层色谱法、气相色谱法、加压液相色谱法规定更加精密的仪器，一般提供高分离度，但只能辨认与定量测定非常少量的物料Use of Reference Substances in Identity Tests— In paper and thin-layer chromatography, the ratio of the distance (this distance being measured to the point of maximum intensity of the spot or zone) traveled on the medium by a given compound to the distance traveled by the front of the mobile phase, from the point of application of the test substance, is designated as the RF value of the compound. The ratio between the distances traveled by a given compound and a reference substance is the RR value. RF values vary with the experimental conditions, and thus identification is best accomplished where an authentic specimen of the compound in question is used as a reference substance on the same chromatogram. 原则物质在鉴别实验中的使用：在纸和薄层色谱法中，从试样点开始的某个特定化合物在介质上的行进距离（这个距离从斑点或者色带的最深点测量）与流动相前端的行进距离的比例被规定为该化合物的RF值。

某个特定化合物和原则物质的行进距离之间的比值是RR值RF值随着实验条件而变化，因此最佳有待检化合物可靠的原则品作为参照物质并在同一色谱条件下完毕鉴别实验For this purpose, chromatograms are prepared by applying on the thin-layer adsorbent or on the paper in a straight line, parallel to the edge of the chromatographic plate or paper, solutions of the substance to be identified, the authentic specimen, and a mixture of nearly equal amounts of the substance to be identified and the auth。