I would have two question, hope somebody can help me. So

1, i bought 2,5 litres of petrolether 1,5 years ago but i still have half of it, so the bottle was opened a dozen times then sat on the selve.the expiration says 10.2019 so this was two months ago. I am doing STB extraction at the moment but i dont like the yield.i am doing everything as before but the yield seems too weak. I dont think the plant material has less quality. A year before i got yellow dmt everytime, now the crystals look like glass crystals, at least look very different (much poorer).
Is it possible that the NPS is degrading over time so it can pull less dmt?


2, i am going to purchase fresh petrolether. I can choose from different regarding the boiling point: 40-65C, 60-80C, 35-100C, 50-70C. Which one can pull wider spectrum? (I am not doing warm bath extraction)

Thank you

it should be fine.
the expiration is undoubtedly because of evaporation of the lighter fractions, with lower boiling points.

I'd choose the 60-80 C, that's light naphtha. but the 30-100 C works too.
obviously, the higher the b.p., the longer it's going to take to evap. but you also want the b.p. to be high enough that you can warm the solvent, as it pulls higher yields when warm.

Just a contemplation, maybe it could be true... the petrolether is a mixture of solvents, so the lower boiling point fraction is different solvent than the higher boiling point fraction.

And the wider the boiling point spectrum (like 30-100C) the more it contains of different solvents so the wider of final alkaloid spectrum is pulled (but longer evap time).

I used to have nice yield with 40-65C solvent, so i am a bit afraid the yield will be less if i choose higher boiling point solvent.


Now i suspect that the lower boiling point fraction of my solvent has evaporated as you wrote,this is the reason of much less yield,which i dont like.