The only FACT I say is crucial is not heating above 90 degrees Fahrenheit. Your choice if you want to but check the MSDS (Material Safety Data Sheet) on any flavors that you can find them for. Or The MSDS for Nicotine pure or mixed with base They will all ahow to keep below 90 degrees.
I have found several studies that indicate no degradation at the point you quote. Some not so scientific and others where a lot of effort was put into the study.
I myself was part of a study and blind taste test on steeping at 150F and the conclusion was if there was any degradation at all it was very nominal giv'in the time the finished product would be used by the average vaper.
This study can be found right here in the steeping thread going back about a year.
Here is the result of one such study.
Nicotine degradation and other myths | ALL ABOUT E-CIGARETTES UK
Quote:
So I've been looking into the chemical properties of Nicotine (and cotinine) for a while now, sad huh?
There are a lot of myths and old wives tales circulating but I have been sifting through and corroborating with multiple independent sources where possible.
The first thing that surprised me, is that Nicotine is a highly stable chemical compound!
Here are some info's about which (I hope) I have exhausted obvious error:
Freezing point -79°C.
This means Nicotine won't freeze unless you can get it to -80°C or below.
However the medium in which the Nicotine is contained will freeze at it's respective temperature.
PG -60°C
VG +17°C
Vodka -15°C
(yes it freezes at +17°C, look it up later!)
Flash point +95°C.
The lowest temperature at which it can vaporize to form an ignitable mixture in air.
Solvents such as Vodka, PG and VG will have different flash points.
PG +130°C
VG +170°C.
Vodka +30°C
Auto ignition point +244°C.
The lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark.
Again beware of contaminants and solvents, although it is unlikely to occur in weak solution.
Boiling point +247°C.
The temperature at which it changes into a vapor.
In solution the solvent may boil at a different temperature.
This would result in the suspended Nicotine being carried away in the vapour without itself having boiled.
PG +188.2°C
VG +290°C
Vodka +80°C
Rate of degradation.
Nicotine in PG solution is noted to be stable at room temperature (20°C) when exposed to air and (indirect) sunlight for up to 2 months with only a 2.1% drop in concentration.
This indicates that an open container of Nic/PG base at 54mg would degrade to approximately 52.8mg.
An open container of PG e-liquid at 18mg would degrade to approximately 17.5mg.
Similar minimal degradation (2%) is noted to have occurred after storage in a domestic freezer for around 18 months.
(I only have one source for this, numerous others all appear to cite or plagiarise the original).
Various tests carried out at 40-80°C for up to 20 days appear to show no degradation of Nicotine in PG within a sealed container.
Breakdown of the chemical structure of Nicotine is noted to begin at approximately 300°C in an oxidising environment.
(The flavours and aromas associated with any particular mixed e-liquid would be subject to higher rates of degradation in much less severe environments).
PG - Propylene Glycol
VG - Vegetable Glycerin
Vodka - assumed 37% ABV (Cos that's what I had in me blooming cupboard!)
Cotinine is an anagram of Nicotine.
Menthol prevents the body from metabolising Nicotine so it stays in the system longer.
Nicotine likes Melanin, so if you have dark hair and/or skin you will be hanging onto residual Nicotine much longer than us pale folks.
If you find any pertinent FACTUAL errors in the above then please let us all know.
