Straight answer is no. We have never stated our pure liquid nicotine, (which we never sell without first diluting), is USP grade. The specification (recipe) we have developed has criteria, that if obtained by our subcontracted laboratory on a particular batch, meets European Union pharmaceutical grade qualification. About 60% of our batches meet European Union pharmaceutical grade qualification. United States pharmaceutical grade requires additional certification and verification of the process in action and is not necessary for vaping. It is required for medicine which would include stop smoking aids such as nasal spray, gum and patches.
We use a 6 step extraction process, forgetting the additional certification and verification of the process required for USP grade, we would have to add a 7th and possibly 8th step to hit 99.9% consistently which would add another 15% to 20% to our cost. Sometimes the batches are 99.82%.
Close enough for vaping.
Edit: The real question that should be asked is what is in the percentage not equaling 100%. Example 100% -99.9%= 0.1% or 100% -99.81= 0.18%. What I never see anyone on this forum ask is what is in that 0.1%, 0.18% or for some vendors 2.5%? That is what we test for and what is really important. Is it water, ok fine. Is it solvents not boiled off from the extraction process? Is it heavy metals? And last but not least how many parts per million arsenic content is contained in the nicotine? Testing for these elements determines if the batch is safe or not. All plants have a certain level of arsenic content. Therefore, all liquid nicotine has some arsenic in it. We allow 1 ppm maximum of any of the above except for H20 which is fine.