I found this someone posted from Wizard Labs. I. Saved it in my notes, thought it might be helpful to you also.
Thanks for the enquiry.
Just to clarify, nicotine doesn't have a shelf life as is normally used in
the food industry.
It won't spoil, and be unsafe to consume like a food product.
In the chemical industry, the "expiration date", or retest date, is usually
based on prior stability testing to indicate when a chemical, or solution
should be retested to assure it still meets the original specs for usage.
Nicotine will oxidize in reaction to oxygen, light, heat, and moisture to
form nicotine oxides.
These oxides are strongly colored, and are responsible for the yellow,
brown, and sometimes pink or red shades that you may see develop in nicotine
solutions over time.
In addition to the color change, the solution may develop a stronger
characteristic nicotine aroma, and taste which might interfere with very
light, or delicate flavorings.
When this happens it doesn't mean that a solution is now unusable, but
depending on individual tastes, you may find a heavily oxidized solution
only suitable for use with tobaccos (some find this even preferable), or
other strong flavorings.
While you cannot completely prevent the oxidation process once the pure
extract has been opened and mixed, there are a few storage procedures you
can follow to reduce exposure, and keep the solution as close to it's
original state for the longest period of time as possible.
Nicotine solutions should be stored in amber glass containers with a tight
fitting cap to prevent exposure to oxygen, light, and moisture.
If a nicotine solution is going to be used immediately over the course of a
few weeks, leaving it in the plastic shipping container is acceptable, but
if longer storage is needed, the solution should be transferred into glass
containers due to their superior oxygen barrier, and non-reactive
properties.
*** NOTE: Always properly label any rebottled solutions and chemicals! ***
To avoid repeated exposure of the entire solution to oxygen and moisture
during use, we recommend that the solution be divided up among several
smaller amber glass bottles instead of stored in one large bottle.
This way, you can take one small bottle from storage for short term use
while leaving the other bottles sealed, and untouched until needed at a
later date.
Store the filled amber glass bottles in a freezer to help slow down
molecular movement, and chemical reactions in the solution.
When filling the amber glass bottles, leave a minimal air space at the top
of the neck (approximately 1/4") for possible heat expansion when the bottle
is removed from cold storage, and allowed to warm to room temperature again.
Storage and handling recommendations are the same for both propylene glycol,
and glycerin based nicotine solutions.
On a side note, during our stability testing we've consistently witnessed
faster oxidation of VG based solutions in comparison to PG based solutions.
Whether this is due to a difference of hygroscopic properties, retention of
microbubbles during mixing, or other factors is unknown, but I thought I'd
include that for your own interest.
Thanks again for the good questions, and if we can be of any further help
just let me know.
Best regards,
J. M.
Wizard Labs
