A black line across my developed TLC plat

[Felic]

TO Mr Krickos
I have already try the preeluting plat, however the black line still appeared. As you stated before about my work concerning the spot might be submerged in the mobile phase, I think it was not the problem because we have tried to work properly. Nowadays, I become believe that it may be caused by the purity and interaction of the mobile phase, Mr.

[unmgvar]

i know that it is a crazy question
but are you drawing the plate?
many do this by drawing a pencil line on the plate to create a grid for the samples and the sample loading position

[Felic]

There is no crazy question Mr/Mrs/Ms unmgvar =D
Absolutely not.
However, is it does a matter by drawing the line by pencil since the carbon of pencil absolutely doesnt have any chromophores to give any absorbance. Thank you before.

[HW Mueller]

Is your black line disappearing when you dry the plate? That is, are you talking about separation of mobile phase, as I remember that Tom mentioned already?
Incidentally, what makes you think that a black substance, as in pencils, "absolutely" does not have a chromophore??