Impregnated Layers

TLC layers with special properties can be made by adding reagents to the silica gel slurry when the plates are made, or after, by dipping the prepared TLC plate into reagent solutions, or predeveloping them with the reagent solution. Since the prepared layers of this type are limited, and might age if not used, they are prepared mostly by the latter two methods. After drying and activation, they are used in the normal manner.

The most often used impregnated layer is that made with a 1-5% solution of silver nitrate in methanol. This impregnation allows geometric cis/trans or C=C bonded isomers to be separated, usually with various lipid mixtures. If made by impregnation, they must be dried and stored in the dark, and wrapped in aluminium foil so that oxidation caused by light does not occur.

Other useful impregnated layers found in the literature include 1% potassium oxalate aiding in the discrimination of polyphosphoinositides, 5-10% magnesium acetate aiding in the separation of phos-pholipids, and 5% ammonium sulfate, which allows a TLC plate to be charred without spraying with sulfuric acid or other reagents. Whether this dry reagent charring does as good a job for a particular class of compounds as other charring reagents should be investigated.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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