I just discovered that the Whatchamacallit STB Tek recommends using a PET plastic container as a DIY Sep Funnel (read: bad choice). Embarrased that I recommended this inappropriate material to another site member, I sought out a good source of information to ascertain material choices.

Sure, in general, HDPE is a good bet, but there are still several compounds that are incompatible with that material (like butane, or Trimethylbenzene).

Here is a great (and thorough) database where both skilled and noob chemists can confirm the compatibility of their containers, solvents and regents, brought to you by Nalgene: Materials Chemical Resistance Database

If you are not absolutely sure of the appropriateness of your container, don't assume like I did; LOOK IT UP!

Thanks for this post. Quality of plastics and plasticizers being leeched into extractions is something that is often overlooked, yet precautions need to be properly executed to ensure a pure product is obtained.

Also, even if you have a HDPE container, they are coated with plasticizers which are carcinogenic. And also, what about the cap you are using? They are most of the time not HDPE, and I have seen with my own eyes how badly those things can warp. After an extraction, you can't even close the jug because the plastic has been warped via leech.

Aye, that's why I use quality bottles from SKS Bottle and Packaging-- would definitely recommend them.

For STB, I use their Natural HDPE Leak Proof Narrow Mouth Rounds. It has a polypropylene leakproof cap, which is good for Naptha and NaOH-- and they are inexpensive.