Quantifying PG : VG ratio and nicotine content in commercially available e-liquids using handheld Raman spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemical Sensing

Background:

• Electronic cigarettes (e-cigarettes) are increasingly popular nicotine products, posing challenges for rapid quality control.
• Traditional e-liquid analysis methods (chromatography, mass spectrometry) are slow and lab-based.
• There is a need for quick, portable analytical tools for e-liquid ingredient verification.

Purpose of the Study:

• To develop and validate a rapid, portable screening method for e-liquid analysis.
• To quantify the propylene glycol:glycerol (PG:VG) ratio in e-liquids.
• To determine the nicotine content in e-liquids.

Main Methods:

• Utilized Raman spectroscopy combined with chemometrics for e-liquid analysis.
• Developed a method for simultaneous quantification of PG:VG ratio and nicotine content.
• Validated the method against commercial e-liquid samples.

Main Results:

• Successfully quantified the PG:VG ratio in 20 out of 23 commercial samples within 3% of stated values.
• Quantified nicotine content within 1 mg g^-1 for 16 out of 23 samples.
• Achieved high linearity in quantification, especially with constant flavor profiles.

Conclusions:

• Raman spectroscopy offers a fast, inexpensive, and portable complementary technique for e-liquid quality control.
• The developed method accurately determines key e-liquid components, aiding in product safety and regulation.
• Further research can address limitations and expand the application of Raman spectroscopy in e-liquid analysis.