I store it in the jar. Never have seen this before though. I'll try tossing the solution and using 'new'. Thanks!Where did you have the paper stored and where did the chromatogram hang to dry? It looks like it was exposed to an acidic environment or an acid gas like so2. Also, if your solvent has been open to the air for a long time, or stored in the chromatography jar, it will decrease in strength causing a similar result.
Interesting. This one dried in the same location as my last one (which turned out fine).I just had this happen to me in September. Dried so light that I couldn’t accurately read it and Had to re-test.
I believe it was caused by sunlight. I did my test at 1 location and brought to another during the drying period. Chroma paper sat in my truck for a few hours. I’m not sure if it got sunlight or not, but obviously less than ideal drying conditions. And is what I attributed to the fading. Same solvent the next day dried properly.
Lol. My chromatography kit’s instructions must have been missing that page.Whether it's right or wrong, I put mine on the suction side of a fan. It usually dries in 3-4 hours. Only did 4 tests but they all dried in similar times. It's kind of funny though because if I don't move the paper you can see the shape of the fan guard on the paper but it goes away.
I was going to suggest cold as a possible issue. I was drying one out in my garage during a colder than normal day and it had a very yellowish appearance. Brought it inside to my normal hanging place in the basement and it colored back up (ie. I think it dried the rest of the way like yours did) though it never became as dark as ones I had dried in warmer conditions.Well, another 12 hours seems to have done the trick. Maybe its just colder than normal down in the basement and it took a while to fully dry.