外文过柱子资料.doc

? TLC Visualization Reagents This is a brief selection of the many available TLC visualization reagents. Below each title is the type of compounds or structure which can be detected with the specific reagent. When beginning work with these reagents, acquire any MSDS (material safety data sheets) to see if there are any extra precautions needed in safely using them. Before spraying, plates should be well dried in the hood of residual solvents and components. Amines and organic acids used in the mobile phases may adversely affect the visualization reaction being attempted. If heating to remove these components is done, consideration should be given so that loss of components or their decomposition is avoided (by lowering the temperature or using a shorter time in the oven). Always spray any of these reagents onto plates in a well ventilated hood while wearing safety glasses. Also apply moderate amounts to the plate so it always appears dull and flat (if it looks wet, you have sprayed too much). You can always overspray to enhance the detection. Aluminium chloride For flavonoids Spray plate with a 1% ethanolic solution of aluminum chloride. Results: Yellow fluorescence in long wavelength UV light (360nm) 4-Aminoantipyrine/potassium hexacyanferrate (III) (Emerson reaction) – check something missing (Emerson reagent) for the detection of phenols and arylamines Solution I: 1g aminoantipyrine (4-aminophenazone) in 100ml 80% ethanol Solution II: 4g potassium hexacyanoferrate (III) in 20ml water, fill to 100ml with ethanol Procedure: Spray with solution I Dry 5 minutes with warm air Place chromatogram in a chamber with vapor from 25% ammonium solution, making sure that the layer does not contact the liquid. Results: Red-orange to salmon pink spots 2-Aminoethyl diphenylborate, see Ethanolamine diphenylborate Ammonium metavanadate, ammonium monovanadate, see Vanadium(V)sulfuric acid reagent Ammonium molydbate For detection of phosphoric acid derivatives S