Tuesday, May 21, 2019

What detectors are used in high performance liquid chromatography (HPLC)?



Polarity
The arrangement of atoms and the corresponding bonds in a molecule determine its activity, structure, and physiochemical properties. A particular arrangement of these atoms and their corresponding bonds (called functional group) is responsible for the characteristics and chemical reactions of the molecule. This structure helps in finding out the polarity of the molecule. Hence, two separation methods use these principles, Normal-Phase HPLC and Reversed-Phase HPLC. The Normal-Phase HPLC has one non-polar mobile phase and one polar stationary phase. The Reversed-Phase HPLC has one polar mobile phase and one non-polar stationary phase.

Molecular Size
This separation characteristic is commonly used in Gel Permeation Chromatography which separates analytes using the molecular size as the basis. Usually, polymer analysis uses this technique.
Electrical Charge
Contrary to polarity-based techniques, in electrical charge-based techniques such as ion-Exchange Chromatography, opposites attract and likes repel.

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