The impurities are not detectable on TLC plates but in hplc run they interfere with major peak determination.
Could you reformulate your question giving more information. There is not one speedy way to remove minor impurities. The method of choice to purify your standard depend of many variables. Some times you can use recrystallization, distillation, solid or liquid extraction or chromatography. Some times if you don't have enough sample is better just to get a new standard. Please be a little more specific about your standard.
assuming you are stuck with UV detection, changing the wavelength might help (i.e., the impurity may have different spectrum than the pure substance). It must be present at quite high levels to interfere with a pure substance present at >90% or >95%.
Thank for your answer Gregory, but I m in seek of simultaneous method of analysis of more then one active ingredient. Finding wavelength again and again didn't work well. I bought the standards about one year ago and now they seems to have minor impurities that is more than one peaks. May be my standards degraded. I want to use the same because its really costly for me to buy new ones. As far as Column chromatography (cc) is concerned, I have already mentioned that the impurities are not visible on TLC. If someone has better idea please cpmment.........
I again say for silica gel colomn just pass your standard through about 10-15 cm colomn ,impurities will adsorb on silica, no need of TLC then check it direct through (HPLC or GC).
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