Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: TLC Reference paper
GreenD
International Hazard
*****




Posts: 615
Registered: 30-3-2011
Member Is Offline

Mood: Totally f***ing high, man!

[*] posted on 31-5-2013 at 10:16
TLC Reference paper


Need help understanding something again; odd description of developing TLC, in context they are trying to separate
monoacylglycerides/diacyglycerides/tri- of long-chain fatty acids.

Five/ul (50 units) of enzyme solution was spotted onto the pre-adsorbent area of a silica gel plate (Type LK6, Whatman Inc., Clifton, N J, USA) impregnated with 3.0% boric acid and dried for 2 h at 150°C, and I gl of the substrate mixture containing 76 wt% glycerol, 19 wt% of oleic acid and 5 wt~ of water was then layered. After 20 min at room temperature, the plate was pre-developed in the pre-adsorbent area twice with diethylether and then; developed with CHCl3/acetone (96.4, v/v). The spots were visualized by spraying 50~0 sulfuric acid followed by heating for 20 min at 150°C.

confused about the bold




ʃ Ψ*Ψ
Keepin' it real.
Check out my new collaborated site: MNMLimpact.com
View user's profile View All Posts By User
DJF90
International Hazard
*****




Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline

Mood: No Mood

[*] posted on 2-6-2013 at 08:57


They're using plates with a pre-concentration area. You spot below the baseline, where the pre-concentration area is, and when you elute it the compounds migrate quickly up to the baseline, giving a tight spot. This is then developed with the desired solvent system to run the actual TLC. It looks like they pre-eluted twice, just to get everything up to baseline. Diethyl ether is only weakly polar, and so I assume that it will only carry material through the pre-adsorbent zone to the TLC baseline.

If you want to do this, and don't have pre-adsorbent plates, just spot normally and run the TLC in 4 %v/v acetone in chloroform.
View user's profile View All Posts By User
GreenD
International Hazard
*****




Posts: 615
Registered: 30-3-2011
Member Is Offline

Mood: Totally f***ing high, man!

[*] posted on 3-6-2013 at 10:52


Ok, thanks. I don't see the necessity of doing this, but understand it now, at least.



ʃ Ψ*Ψ
Keepin' it real.
Check out my new collaborated site: MNMLimpact.com
View user's profile View All Posts By User
DJF90
International Hazard
*****




Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline

Mood: No Mood

[*] posted on 3-6-2013 at 11:44


If the extract is dilute it allows you to apply a reasonable amount of material to the plate without it all spreading out with the repeated applications. Pre-elution then gives a nice tight spot on the baseline, ready for elution with the chosen solvent system.

Peach is fine by the way...
View user's profile View All Posts By User

  Go To Top