Most of the alkaloid content extracted during an ethanol extraction (or a NET extraction in general) will be in the salt form. As such, these salts are not amenable to titration. One forum member used a cold ethanol extraction awhile back and was able to get more alkaloid salts relative to the copious amounts of junk that a NET extraction typically pulls out. This resulted in a liquid that, while unable to approach WTA alkaloid levels, contained perhaps several times more alkaloid salts than a typical NET extraction (somewhat low -vs- very low levels).
When researching the alkaloid content of tobaccos, one often finds literature stating that the alkaloid content of many tobaccos are on the order or 2 - 3 percent. In practical terms, these figures are overly optimistic. In extraction after extraction, using many different tobaccos, I've found that 1.0 - 1.2% is about the limit of the alkaloid extraction. In other words, if I extract 100 grams of tobacco and process it to purify WTA, I'll end up with about 1 gram of purified WTA... and this from a very efficient extraction process.
On a good day, a PG-based NET extraction might pull out about half of the alkaloids present along with a great deal of non-alkaloidal tobacco material. This assumes using heat and a lot of contact time. An ethanol extraction might be expected to do a bit better. It depends largely on the amount of ethanol used and the contact time with the tobacco. Shorter NET extractions tend to be cleaner NET extractions, but they also contain fewer alkaloids.
It's very difficult for me to speculate on what the actual alkaloid concentration in a NET extraction might be. For example, if someone were to heat up 500 mL of PG and soak 100 grams of tobacco in that PG, perhaps 500 mg of alkaloid salts would be extracted. Of the 500 mL of PG, perhaps 100 mL would be lost due to being soaked into the tobacco, so 400 mL of NET could be recovered. This 400 mL of PG-based NET extract might contain 80% of half the alkaloids present in the tobacco (50% alkaloid removal and 80% PG recovery). In other words, the PG might pull out 500 mg of alkaloids, and 100 mg of the alkaloids would be retained by the PG left in the tobacco. So the alkaloid content of the PG-based NET would be 400 mg / 400 mL, or about 1 mg/mL. This is assuming that the NET extraction would not have to be further diluted to a vapable level.
The reason a WTA liquid can contain such greater alkaloid concentrations than a NET is the fact that the WTA process eliminates all the non-alkaloidal tobacco gunk. Thus, one can have a 24 or ever 36 mg WTA liquid that is only very lightly colored due to the alkaloids having been isolated from the rest of the tobacco material.
