So I had spotted this TLC plate with different lipid standards (their identities are known). The thing I'm wondering about though is, when I spotted oleic acid, I got a huge expansive blob at the top of the solvent front. Also, with phosphatidylethanolamine, it created faint streaking above and below the point. I'm wondering though, what could cause this? Method = iodine staining.Phosphatidylethanolamine
I tried looking up some information about possible bands/streaks, but the best I could come up with (besides bad spotting) is something about the difference in hydrocarbon compositions of the streaks. The article said if I were to take samples of the streak above and below, I would find more polyunsaturated fatty acids above and more saturated below. However, it was talking about phosphatidylcholine in bovine retina cells -- I was working with egg yolk.
They gave some reason, which was this: When phospholipids from rod outer segments are subjected to TLC on silica, partial resolution into groups of molecular species occurs (Roque and Giusto, 1995).
I'm not really quite sure what it's saying here, however.
I'm certain there must be something to it, because I wasn't the only one who observed this streak. And it doesn't seem like your conventional 'bad spotting' streak, either. Oleic Acid
I'm not sure what to think of this one. Most of the stuff I come across attributes it to bad spotting but again, I feel like there has to be a reason why the spot is so expansive (other people in my lab got it as well). Could it also have to do with the large hydrocarbon tail? I would have assumed the points would have been slightly 'neater' (especially since I am dealing with standards here).
Any way, any help would be greatly appreciated -- thanks!
Oh, I've attached my TLC plate photo in case you wanted a better view. Photo isn't the best, but I assure you, the mentioned points were there. Oleic was spotted 2nd from the right, phosphatidylethanolamine was spotted 4th from the right. Looking at it now, I wonder if that large spot at the top might be from the triglyceride sample (spotted at the 1st point from the right).