Ok, so you need to do some TLC spotting and either your supervisor/teaching lab can’t afford to buy the expensive ones, or someone else in the lab has “moved” them. Pasteur pipettes are never ideal as they’re too wide and you want to spot the TLC plate, not blotch it! We’ve all seen those….
Here’s a short and sweet method to getting that TLC plate done and analysed.
Easy Solution – Make Your Own
1. Take a glass capillary tube and heat it gently over a Bunsen flame. Remember that the tube will get hot, even at the ends, so hold it carefully using tweezers.
2. Once the middle section of the capillary tube is hot enough you’ll find that you can pull apart the two ends quite easily. You need to do this quickly in order to draw out the middle section into a very thin point. You’ll get the timing right with practice.
3. Pull the ends until the tube snaps and shorten the two halves at the thinnest end until they measure around 1-2 inches in length. This is a good size to use as any longer and they have a tendency to snap when you apply pressure on the TLC plate.
4. Make sure the ends are smooth and flat for consistency when loading your material.
That’s all there is to it! It often takes several attempts to get good TLC spotters, but once you know how, you’ll find you can make them to whatever size suits you best. Keep them safe and they’ll be your best friends in the lab!
Practice makes perfect…..
Image attributed to: http://www.flickr.com/photos/54353022@N05/5035705332/
Preparative thin-layer chromatography separation of C60-fullerene derivatives over silica-gel. Bad separation… amazing result!!!