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E-liquid analysis is fundamental in ensuring e-liquid quality and safety. Different analytical techniques are used by manufacturers during the development and production of these substances. However, refractive index and density determination are two of the most important parameters used to determine propylene glycol (PG) and vegetable glycerin (VG) concentrations. By assessing the PG and VG content, manufacturers can not only control the quality but also tailor the flavor, intensity, vaporization characteristics, and more, ensuring that the best product is produced for the customer.
In this application note, you will learn:
- More about the background of quality control for e-liquids
- The best materials and methods to determine PG/VG
- The techniques and temperatures of measurements specified by USP, EU, FCC, and European Pharmacopoeia
- Additional information about the results obtained, as shown in the figure below
- And more!
Density dependence as a function of different PG/VG ratios.
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Black dots are the experimental data points, the red solid line represents the quadratic fit. The red-dotted line indicates the density-PG/VG ratio relationship for the 55/45 % w/w sample. |
What does e-liquid mean?
E-liquid refers to a liquid solution used in e-cigarettes, which heats the e-liquid, producing a vapor that the user inhales. Other names for e-liquid are e-juice or e-fluid. E-liquids generally contain different levels of nicotine and flavors, in a base of propylene glycol (PG) and vegetable glycerin (VG) in various concentrations. E-liquid manufacturers must verify the concentration of each substance as well as the final product. Two common, simple, and accurate techniques are used for concentration verification: density measurement and refractive index.
Download our application note to learn more about measurement procedures and how accurate the results are when using METTLER TOLEDO's Excellence Density Meter and Excellence Refractometer.
