heptane a/b

[TalkingGarden]

Hey guys! Quick question. I have done a/b with nap. a few times but just did one with lab grade heptane. Well I will say the crystals are huge! However one area of the plate there is big crystals on top of a SUPER THIN layer and this thin layer looks to have a VERY SLIGHT light blue tint if ya catch it at the right angle. I never saw this before but first time using heptane is this normal has anyone encountered this? is it safe?

 

[endlessness]

Did you do an evap test with your solvent? If not, do it!

Clean heptane should evap totally without leaving any trace.

 

[TalkingGarden]

Thanks for answering so quick! But yes I have done it in the past and just did it again to double check! I have used this same heptane for re x before with no issues just not for the whole extraction. The only thing I did differently was the plate was sitting around for a while and was slightly dirty before use so I wiped the plate down with iso alcohol but I don't think that would do anything as I wiped it up with a paper towel and didn't see any residue at that point. It looked dead clean. But that is the ONLY thing I did differently besides using the heptane from the start.

I will try to snap a pic in a little bit

 

[endlessness]

If it is clean , you did an evap test and its fine, and you have used it in the past, then you shouldnt worry about it, but.. in case there was any other variable like a dirty plate or maybe an isopropanol that isnt clean or whatever else it can be, then I suggest you re-x your crystals. That way you will get the worry out of your mind, it´s not good to travel to another dimension while worrying about your health hehe

 

[TalkingGarden]

So I don't know what happened but after I left it out for a while the blue went away. This would lead me to belive that it wasn't fully dry or something but now sure how that could be as it went infront of a fan for a while then even into a vac chamber for a bit! So I don't know but looks fine. When I scraped it up didn't notice anything weird either so I think its good to go...like I said I have used the heptane to re x before with no issues so should be fine!

Endlessness than you for the help!

 

[downwardsfromzero]

My first thought was that the blue coloration resulted from diffraction because of a thin layer of 'something'.

Fortunately, it seems, that something turned out to be volatile (or got thicker??)