I find myself curious about the distinction between nicotine and free nicotine. Anybody have any idea what it means?
I was under the impression that tobacco companies guard this data closely, so how did you happen upon this information?
Anyway, in scientific terms, "free nicotine' is "unprotonated" and "unbound" nicotine. Free Nicotine is the component that is rapidly transmitted to the brain, thereby delivering the "nicotine kick" that tobacco users' seek. Apparently, tobacco companies exploited this knowledge by lowering the total nicotine yield while simultaneously manipulating the pH level of the tobacco in order to make a larger percentage of the total nicotine be Free Nicotine. In short, they could advertise and sell "low nicotine" cigarettes (that complied with government regulations!) that actually delivered similar amounts of (or perhaps more) Free Nicotine, thereby making them more addicitive.
The bottom line is that it appears that it is the Free Nicotine number that matters most when comparing the nicotine yield of multiple snus products. So, the question becomes: do we have access to Free Nicotine data for all of the snus products available to us?
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Despite its importance, the subject of Free Nicotine is so far below the radar for mainstream internet users, that it doesn't even have a Wikipedia entry.
However, if you would like to learn more about Free Nicotine, here are just a few of the many articles available online that touch on the subject:
More on the regulation of tobacco smoke: how we got here and where next -- Gray and Kozlowski 14 (3): 353 -- Annals of Oncology
Smokeless Tobacco and Some Tobacco ... - Google Books
SpringerLink - Book Chapter