emcat Posted August 5, 2017 Hi, I've recently developed an interest in lichens but found you really need to use TLC to ID to species level. While I have used TLC before at uni, I don't really have access to their labs for this. It's easy enough to buy silica sheets for TLC but the reagents are a bit more difficult. Mainly because they need to be bought from lab supply shops that don't generally sell to individuals. At the moment reagent C is really the only one that seems easily obtainable. Was wondering if anyone might be able to give advice on where/how these might be obtained (legally)? The list is below. Cheers A toluene / dioxane / acetic acid (180 : 45 : 5) Dioxane in solvent A is hygroscopic and absorbs water over time. The solvent thus rapidly deteriorates and accurate Rf-values can only be recorded with relatively fresh solvent. B hexane / diethyl ether / formic acid (130 : 80 : 20) This solvent has largely been replaced by B'. B will deteriorate in less than 6 hours whereas B' can be used up to four or five days. B' hexane / methyl tert-butlyl ether / formic acid (140 : 72 : 18) C toluene / acetic acid (170 : 30) For most lichen substances C provides the best discrimination. It is also very stable (several weeks) and therefore is the most common solvent routinely used. Solvents E and G are mostly used only to discriminate substances which will otherwise not be resolved very well: E cyclohexane / ethyl acetate (75 : 25) Solvent E discriminates between non-polar derivates of lichen compounds and substances which have very high Rf-values in A, B, B' and C. It needs to be prepared fresh daily. G toluene / ethyl acetate / formic acid (139 : 83 : 8) Solvent G is very stable and discriminates well between substances with very low Rf-values in A, B, B' and C. Share this post Link to post Share on other sites
