Thin-layer chromatography purity test

Ferenczi-Fodor, K., Vegh, Z., Renger, B. Thin-layer chromatography in testing the purity of pharmaceuticals. Trends Anal. Chem. 25, 778-789 (2006)... 

Years of doing things the same way does not validate correctness. Many chemical tests have been proven incorrect over a period of time. Newer techniques like thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and mass spectrometry (MS) have revolutionized our standards of purity. So, too, should this testing procedure prove to be. 

Thin-layer chromatography (TLC) is commonly used for the determination of radiochemical purity in nuclear medicine. TLC was described as early as 1967 for testing radiopharmaceuticals (Hoye 1967). Since the introduction of TLC (Izmailov and Shraiber 1938 Stahl 1956), a variety of modifications and new applications have been reported (Fairbrother 1984). 

The technical compound EPN was supplied by Promochem, West Germany. The purity of the sample was tested by thin layer chromatography. Stock solution was prepared by dissolving the required amount of EPN in dimethylformamide (DMF) as a solvent and making up with the supporting electrolytes to get the desired concentration. All the supporting electrolytes used in this work were of analytical grade. 

E. lllner. Purity testing of sorbose and sorbitol by thin-layer chromatography on Silufol ready-prepared plates, Pharmazie 39 689-690 (1984). 

The easiest way for most people to check a psychedelic compound s purity is at a testing station, such as Street Pharmacologist (Box 610233, Miami, FL 33161, 305/ 446-3585), or PharmChem. PharmChem s analysis is based on thin-layer and gas chromatography and involves comparison with 300 possible psychoactive substances and some 250 possible impurities. 

Hexamethylcyclotrisilazane and hexamethylcyclotrisiloxane were purified by rectification in vacuum following which their purity was tested by gas chromatography. Plasma polymerizations were carried out in an electrode system described previously ( ). Thin film were deposited in a 20 kHz glow discharge on the surface of stainless steel electrodes or on gold or silicon electrodes in the case of thin layers intended for further studies of electrical properties. All polymerizations were carried out at constant discharge parameters current density j = 1 mA/cm2, discharge duration t = 30 sec, monomer vapour pressure p = 0.3 Torr. 

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