What Types of Precoated Layers Are There

For special separations, an impregnation of the layer is often necessary, e.g. of unsaturated fatty acids with silver nitrate or of antibiotics of the tetracycline type with EDTA. Whereas the user must perform these impregnations himself, a caffeine-impregnated HPTLC precoated layer is available for the determination of polycyclic aromatic hydrocarbons. 

Sorbent material Chromatographic principle Typical applications 

Aluminum oxide Adsorption chromatography due to polar interactions Alkaloids, steroids, terpenes, ahphatic, aromatic and basic compounds 

Unmodified cellulose Partition chromatography due to polar interactions Amino acids and other carboxyhc acids as well as carbohydrates 

Acetylated cellulose Depending on acetyl content transition from normal phase to reversed phase chromatography Anthraquinones, antioxidants, polycyclic aromatics, carboxyhc acids, nitrophenols, sweeteners 

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