I need tips to obtain the best separation of spots on Tlc , and how to avoid the most common mistakes when making Tlc regarding solvent and elution system???
Read thoroughly theory and practice of TCL.If one dimensional TCL doesn't resolve the components well go for two dimensional one. Right choice of solvent/s, preparing and developing the chromatoplate well, preparing the sample well, using right detection technique, spotting the sample on the base line with soft hands are some of precautions that can be taken to get sound chromatogram.
In order to get best separation one should take care of following things
- 1. Selection of proper mobile phase .one should wisely choose proper combination of solvent system which consist of polar and non polar component depending upon separation of different TLC spot . This liitle trial and error based i.e if spot sticks to base line .one should increase polar component . If spots are near to solvent front means we need to increase non polar component . the principle involved in TLC system is the eluting power of solvents increases with polarity. Therefore, low polarity compounds can be eluted with low polarity solvents, while higher polarity compounds require solvents of higher polarity. The stronger a compound is bound to the adsorbent , the slower it moves up the TLC plate.
- 2.The length of TLC plate should be appropriate
- 3.Tailing due to Mobile phase must be nullified or minimized .
(some time a drop of ammonia or drop of acetic acid works well in this regard)
- 4. Mobile phase must be anhydrous ( Free from moisture)
- 5. TLC plate should also be anhydrous ( Free from moisture)
Dear colleague. try to optimise you system solvent by doing a lot of tlcs with different systems, in order to identify the most suitable one:
first try developping your plates with a solvent from different groups, then try the combinations, check the picture and presentation below for more details. i hope it will help you...
Best regards.
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