Density and Refractive Index Quality Control of E-liquids

The application gives the density (DE) and refractometry (RE) techniques that can be used to determine the Propylene glycol  (PG) and vegetable glycerin (VG) concentration ratio in E-liquids.

Background:

E-liquid refers to a liquid solution used in ecigarettes. An e-cigarette heats the e-liquid, producing a vapor that the user inhales. Other names for an e-liquid are e-juice or e-fluid.

E-liquids generally contain different levels of nicotine, flavors, in a basis of propylene glycol (PG) and vegetable glycerin (VG) in different concentrations. Depending on the PG/VG ratio, eliquids properties can be modulated to meet customer's expectations. Since PG is tasteless and odorless, there is little or no flavor distortion, whilst VG contains preexisting flavor and sweetness: this means that in many cases the added flavoring will be diluted and final product will be sweeter. Thus higher PG-content e-liquids produces a high flavor intensity and throat hit, while higher VG-content tends to deliver duller flavors. PG/VG percentage modulation contributes to tune thickness and density vapor cloud. Furthermore, also the time and power needed to reach the level of vaporization can change: the higher viscosity of VG compared to PG typically requires more power and longer times to achieve optimal vaping temperature.

Download the application for measurement procedures, results and conclusions using Excellence Density meters and Excellence Refractometers.