\[R_f = \frac{\text{斑点中心移动距离}}{\text{溶剂前沿移动距离}}\]\[R_f = \frac{\text{distance moved by spot}}{\text{distance moved by solvent front}}\]
含义Meaning
薄层色谱和纸色谱中衡量化合物迁移程度的量，0 ≤ R_f ≤ 1。极性固定相（硅胶）上，极性越大的化合物 R_f 越小。
In TLC and paper chromatography, the fraction of the solvent-front distance moved by a spot (0 ≤ R_f ≤ 1). On polar silica, more polar compounds have smaller R_f.
符号说明Symbols
| 符号Symbol | 含义 Meaning | 单位 Unit |
|---|---|---|
| \(R_f\) | 比移值retardation factor | 1 |
推导Derivation
按定义从原点量起两距离之比。
Measure both distances from the origin.
与保留因子关系：\(R_f = 1/(1 + k)\)（溶质在流动相中的时间分数）。
Related to the retention factor: \(R_f = 1/(1+k)\).
适用条件与局限Assumptions & limitations
受吸附剂活度、展开剂组成、温度、湿度、点样量影响，鉴定时应与标准品同板对照。
Depends on plate activity, eluent, temperature, humidity and loading; run standards on the same plate.