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ASK THE
SCIENTIST
How does chemical testing
of e-liquids happen?
How are e-liquids tested? How do you know how much nicotine is
in your e-liquid? Columnist Richard Cunningham, PhD, explains the
intricacies of chemical analysis for nicotine vape products.
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icotine e-liquids come in a variety of strengths up to a
maximum of 20mg per millilitre across EU states, while this
can be even higher in other countries. Basically, this is the
amount of nicotine in milligrams for every millilitre of liquid. For a
20mg-strength liquid in a standard 10ml bottle, there would be a total
of 200mg nicotine.
So how can we determine nicotine content?
The simplest method for testing nicotine content is acid-base
titration. This is where an acid is used to neutralise a basic solution,
or vice versa, wherein by knowing the volume of liquid and its exact
concentration added we can calculate the quantity of substance
under study.
In order to visualise the end point, which is when neutralisation has
occurred, there are multiple methods available, but a simple way
is through the addition of an indicator solution. One example is
bromothymol blue. Under basic conditions the solution will appear
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