Chromatography · 色谱法
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| chromatography/krəʊməˈtɒɡrəfi/ | 色谱法 | sè pǔ fǎ |
| solvent/ˈsɒlvənt/ | 溶剂 | róng jì |
| Rf value/ˌɑːˈref ˈvæljuː/ | 比移值 | bǐ yí zhí |
Separating colours and substances
- How do forensic scientists separate the dyes in an ink, or the colours in a food?
- With a simple, powerful technique: chromatography 色谱法.
分离颜色和物质
- 法医科学家如何分离一种墨水中的染料,或一种食物中的颜色?
- 用一种简单、强大的技术:色谱法(chromatography)。
Chromatography route · 色谱法路径
Watch a mixture separate as the solvent front moves. · 观察混合溶剂前沿移动时混合物的分离情况。
Chromatography separates a mixture because its components: · 色谱法能分离混合物是因为其组分：
Different speeds separate the substances. · 不同的速度将物质分开。
How chromatography works
- A spot of the mixture is placed on paper, and a solvent 溶剂 moves up through it.
- Different substances travel at different speeds, so they separate into spots.
Paper chromatography separates a mixture as the solvent rises up the paper
色谱法如何工作
- 把一点混合物放在纸上,而一种溶剂(solvent)向上穿过它移动。
- 不同的物质以不同的速度移动,所以它们分离成斑点。
纸色谱法在溶剂沿纸上升时分离一个混合物
A more soluble substance will travel: · 溶解度更高的物质将移动：
More soluble components move further. · 溶解度更高的组分移动得更远。
Reading a chromatogram
- Substances that are more soluble (or less attracted to the paper) travel further.
- Comparing with known substances identifies the components.
A mixture separates into coloured spots that rise different distances up the paper
读一张色谱图
- 更可溶(或较不被纸吸引)的物质移动得更远。
- 与已知物质比较可识别这些组分。
一个混合物分离成沿纸上升不同距离的彩色斑点
A spot moves 3 cm; the solvent moves 6 cm. What is the Rf value? · 斑点移动了 3 cm；溶剂移动了 6 cm。Rf 值是多少？
Rf = 3 ÷ 6 = 0.5. · Rf = 3 ÷ 6 = 0.5。
An Rf value is always between 0 and 1. · Rf 值始终在 0 和 1 之间。
The spot cannot move further than the solvent. · 斑点不能移动得比溶剂更远。
Rf = distance moved by the spot ÷ distance moved by the ______. · Rf = 斑点移动距离 ÷ ______移动的距离。
Rf compares the spot's distance to the solvent's. · Rf 比较斑点距离与溶剂距离。
Rf value 比移值
- The Rf value = distance moved by the spot ÷ distance moved by the solvent.
- It is always between 0 and 1, and is the same for a substance under the same conditions.
Worked example. A spot moves 4 cm while the solvent moves 8 cm. Rf = 4 ÷ 8 = 0.5. This value identifies the substance when compared with known samples.
Rf 值
- Rf 值 = 斑点移动的距离 ÷ 溶剂移动的距离。
- 它总是在 0 和 1 之间,且对一种物质在相同条件下是相同的。
例题。 一个斑点移动 4 cm,而溶剂移动 8 cm。Rf = 4 ÷ 8 = 0.5。当与已知样品比较时,这个值识别该物质。
You've got it
- chromatography separates a mixture as a solvent carries components at different speeds
- more soluble substances travel further up the paper
- Rf = distance of spot ÷ distance of solvent (always between 0 and 1)
你掌握了
- 色谱法在一种溶剂以不同速度携带组分时分离一个混合物
- 更可溶的物质沿纸移动得更远
- Rf = 斑点的距离 ÷ 溶剂的距离(总是在 0 和 1 之间)