USP31-621色谱法 中文译稿

as a parameter of identification. Solutions of the substance to be identified or derivatives thereof, of the reference compound, and of a mixture of equal amounts of these two are chromatographed successively on the same column under the same chromatographic conditions. Only one peak should be observed for the mixture. The ratio of the retention times of the test substance, the reference compound, and a mixture of these, to the retention time of an internal standard is called the relative retention time RR and is also used frequently as a parameter of identification.

在开放柱色谱中，在按照恒定流速条件进行的加压液相色谱法中，以及气相色谱法中，被定义为在样品进样与被洗脱样品区域峰值浓度的出现之间所消耗时间的保留时间，t，可以用于鉴别的参数。待鉴别物质或其衍生物的溶液、对照化合物的溶液、以及此二者含量相等的混合物的溶液须在相同的色谱条件下，使用同一个色谱柱进行连续层析。只能在该混合物观察到一个峰。供试物质、对照化合物、以及二者的混合物的保留时间与内标物的保留时间的比值被称为相对保留时间RR，其也经常用于鉴别的参数。

The deviations of RR, RF, or t values measured for the test substance from the values obtained for the reference compound and mixture should not exceed the reliability estimates determined statistically from replicate assays of the reference compound.

从供试物质测得的RR、RF、或t值与从对照物质和混合物中得到的这些值之间的偏差不得超过从对照物质重复含量测定中以统计学方法确定的可靠性评估值。

Chromatographic identification by these methods under given conditions strongly indicates identity but does not constitute definitive identification. Coincidence of identity parameters under three to six different sets of chromatographic conditions (temperatures, column packings, adsorbents, eluants, developing solvents, various chemical derivatives, etc.) increases the probability that the test and reference substances are identical. However, many isomeric compounds cannot be separated. Specific and pertinent

chemical, spectroscopic, or physicochemical identification of the eluted component combined with chromatographic identity is the most valid criterion of identification. For this purpose, the individual components separated by chromatography may be collected for further identification.

在特定条件下以这些方法进行的色谱鉴别有力地指明了对其的识别，但是不能构成权威性的鉴别。识别参数在3至6套不同色谱条件（温度、柱填料、吸附剂、洗脱剂、展开剂、多种化学衍生物等）下均一致的情况增加了供试物质和对照物质完全相同的可能性。但是，很多同分异构物无法分离。具体的相关化学、分光镜检查、或物理化学鉴别与色谱识别合在一起才是对于被洗脱组分的最有效的鉴别标准。为此，由色谱法分离的单个组分可以收集起来以便进一步鉴别。

PAPER CHROMATOGRAPHY纸色谱法

In paper chromatography the adsorbent is a sheet of paper of suitable texture and thickness. Chromatographic separation may proceed through the action of a single liquid phase in a process analogous to adsorption chromatography in columns. Since the natural water content of the paper, or selective imbibition of a hydrophilic component of the liquid phase by the paper fibers, may be regarded as a stationary phase, a partitioning mechanism may contribute significantly to the separation.

在纸色谱法中吸附剂是适当质地与厚度的一张纸。色谱分离可以在与柱中的吸附色谱法相似的工艺中，通过某单个液相的移动来进行。因为纸含有天然的水分，或者纸纤维对于液相中亲水组分的选择性吸取，可以认为是个固定相，所以分配机制可以对于分离作用明显。

Alternatively, a two-phase system may be used. The paper is impregnated with one of the phases, which then remains stationary (usually the more polar phase in the case of unmodified paper). The chromatogram is developed by slow passage of the other, mobile phase over the sheet. Development may be ascending, in which case the solvent is carried up the paper by capillary forces,

or descending, in which case the solvent flow is also assisted by gravitational force.

另外的选择是使用一个两相系统。这张纸浸渍在其中一个相中，然后其保持不动（如果使用未改性纸，通常选择极性较大的相）。通过将另一个相，即流动相，缓慢穿过这张纸来使色谱图形成。色谱图的形成过程可以是上行的，这样溶剂被毛细管作用力支撑着沿着纸向上，这个过程也可以是下行的，在此情况下溶剂流动也受到重力的影响。

Differences in the value of RF have been reported where chromatograms developed in the direction of the paper grain (machine direction) are compared with others developed at right angles to the grain; therefore, the orientation of paper grain with respect to solvent flow should be maintained constant in a series of chromatograms. (The machine direction is usually designated by the manufacturer on packages of chromatography paper.)

有报道在将沿着纸张纹理方向（纤维方向）形成色谱图与沿着与纸张纹理呈直角方向形成的色谱图进行比较之后，RF值有一定的差异,因此，与溶剂流动有关的纸张纹理定向应该在一系列色谱图中保持恒定。（纤维方向通常由制造商在色谱纸的包装上标出。）

Descending Chromatography下行色谱法

In descending chromatography, the mobile phase flows downward on the chromatographic sheet.

在下行层析法中，流动相在层析用纸上向下流动。

Apparatus— The essential equipment for descending chromatography consists of the following:

仪器：用于下降层析法的基本设备有下列设备组成

A vapor-tight chamber provided with inlets for addition of solvent or for releasing internal pressure. The chamber is constructed preferably of glass,

stainless steel, or porcelain and is so designed as to permit observation of the progress of the chromatographic run without opening of the chamber. Tall glass cylinders are convenient if they are made vapor-tight with suitable covers and a sealing compound.

装有添加溶剂或释放内部压力的入口的气密室。该室最好以玻璃、或不锈钢、或瓷构成，且设计为不用打开该室即可观察层析运行的进展。如果以适当的盖子和密封物确保其密闭，高玻璃园筒即可使用。

A rack of corrosion-resistant material about 5 cm shorter than the inside height of the chamber. The rack serves as a support for solvent troughs and for antisiphon rods which, in turn, hold up the chromatographic sheets.

短于该室内部高度5cm的耐腐蚀材料支架。该支架作为用于溶剂槽以及用于抗虹吸棒的支撑，这些抗虹吸棒依次撑起色谱纸。

One or more glass troughs capable of holding a volume of solvent greater than that needed for one chromatographic run. The troughs must also be longer than the width of the chromatographic sheets.

一个或多个能够容纳多于一次色谱运行溶剂需要量的玻璃槽。该槽也必须长于那些色谱纸的宽度。

Heavy glass antisiphon rods to be supported by the rack and running outside of, parallel to, and slightly above the edge of the glass trough.

玻璃抗虹吸棒将由支架支撑并在玻璃槽边缘之外、与边缘平行、略微高于边缘的位置放置。

Chromatographic sheets of special filter paper at least 2.5 cm wide and not wider than the length of the troughs are cut to a length approximately equal to the height of the chamber. A fine pencil line is drawn horizontally across the filter paper at a distance from one end such that, when the sheet is suspended from the antisiphon rods with the upper end of the paper resting in the trough