BRAINCAKEHigh Performance Liquid Chromatography
High performance liquid chromatography (HPLC) separates the components of a liquid mixture quickly and precisely.
The stationary phase is made of very small solid particles, often silica, tightly packed into a narrow steel column. The small particles give a very large surface area, which improves separation. The mobile phase is a liquid solvent, such as a mixture of methanol and water. Because the particles are packed so tightly, the solvent must be pumped through the column at high pressure.
A small volume of the sample is injected into the solvent stream at the start of the column. Components with more affinity for the stationary phase are held back and take longer to come out. As each component leaves the column it passes a detector, often one that measures ultraviolet absorption, and a peak appears on the chromatogram.
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Key terms in this lesson
- chromatogram
- The output of a chromatography technique, showing a peak for each separated component, used to identify and measure the components of a mixture.
More in Modern Analytical Techniques
- High Resolution Mass Spectrometry
- Precise Molecular Mass
- Chromatography
- Thin-Layer Chromatography
- Gas Chromatography
- Retention Times
- Nuclear Magnetic Resonance
- Chemical Shift
All 15 lessons in Modern Analytical Techniques · All Edexcel A-level Chemistry topics