Best way to quantitatively spot TCL plates?

I like to use 10 uL Hamilton (or SGE) syringes. Used for GC injection they are (when clean) very smooth, accurate (fine point) and reproducible. 1uL makes nice spots. Just be careful not to poke a hole into the plate when you spot it (this doesn't seem to cause too many problems--but, some of your stuff will *definitely* stay behind with the hole).

Most other techniques are tricky if you are interested in quant. densitometry. Most all suffer not from getting sample to the plate, but rather from getting all of the sample onto the plate. For example microcaps are 0.5uL, but I have almost never been able to completely empty one onto the plate, much less in a spot small enough to give decent resolution. Despite this:

I also like microcaps (very expensive here: http://www.voigtglobal.com/manufacturer/652-Chromatography-T...), but the cost might have you pulling El-cheapo Pasteur pipettes into capillaries. These work well too, and are super cheap, but pulling them is a pain in the ass. You will learn that hot glass looks just like cold glass.

The most important thing that I have noticed, is to make sure that your spots are *Completely* dry before running the plates. I can't stress this enough, particularly when you are spotting from a polar solvent such as methanol, water, or God help you, DMF or DMSO. I find that a heat gun works really well. Don't worry if you trash your first (20 ) plate, you will get it eventually.

Cheers,

O3



[Edited on 4-2-2011 by Ozone]

Quote: Originally posted by Ozone

I like to use 10 uL Hamilton (or SGE) syringes. Used for GC injection they are (when clean) very smooth, accurate (fine point) and reproducible. 1uL makes nice spots. Just be careful not to poke a hole into the plate when you spot it (this doesn't seem to cause too many problems--but, some of your stuff will *definitely* stay behind with the hole). Most other techniques are tricky if you are interested in quant. densitometry. Most all suffer not from getting sample to the plate, but rather from getting all of the sample onto the plate. For example microcaps are 0.5uL, but I have almost never been able to completely empty one onto the plate, much less in a spot small enough to give decent resolution. Despite this: I also like microcaps (very expensive here: http://www.voigtglobal.com/manufacturer/652-Chromatography-T...), but the cost might have you pulling El-cheapo Pasteur pipettes into capillaries. These work well too, and are super cheap, but pulling them is a pain in the ass. You will learn that hot glass looks just like cold glass. The most important thing that I have noticed, is to make sure that your spots are *Completely* dry before running the plates. I can't stress this enough, particularly when you are spotting from a polar solvent such as methanol, water, or God help you, DMF or DMSO. I find that a heat gun works really well. Don't worry if you trash your first (20 ) plate, you will get it eventually. Cheers, O3 [Edited on 4-2-2011 by Ozone] Thank you. Very interesting. I have been using some miscellaneous microcaps (from the old days) of 25uL size. These work but as you mention, they are hard to empty completely. I have found this site http://www.discoverysciences.com/product.aspx?id=4272 which sells many types together with a bulb for forcing out the sample completely. I have also a Hamilton micro-syringe but since I have so many tests to do (16 per run) this would be tedious to use. I already have some free-ware densitometry software which I can use by photographing the developed plates with a digital camera. Can I use the micocaps twice, one sample per end?

Quote: Originally posted by Ozone

If you are *very* careful you can use both ends. Otherwise, you can rinse the capillaries with solvent and re-use them. But, if you are going to do that, you might as well use the syringes (rinsing is a pain, either way). Which densitometry software are you using? Cheers, O3

I see Camag have a thing that looks like a tile cutter for doing plates, which is something I was wondering about a while back.

This scanner looks nice, it's probably outside my £9.99 budget.