Rapid determination of 1, 2-propylene glycol and glycerol in refill fluids for electronic cigarettes by Raman spectroscopy

A simple and rapid Raman spectroscopy method for simultaneous determination of 1, 2-propylene glycol and glycerol in refill fluids for electronic cigarettes was developed. Samples of 17 refill fluids were analyzed by a portable Raman spectrometer, and the data were compared with those determined by GC-MS. The results showed that:1) The standard curves of 1, 2-propylene glycol and glycerol determined at the Raman intensity of 522 and 671 cm^-1 possessed good correlation coefficients (R² above 0.999) in the content range of 0.125-0.956 and 0.106-1.120 g/mL, respectively. The results of one sample t-test and independent sample t-test indicated that the Raman method was accurate. 2) The contents of 1, 2-propylene glycol and glycerol in 17 refill fluids were in the range of 0.533-0.766 and 0.182-0.476 g/mL, respectively. The result of paired sample t-test showed that the data determined by Raman spectroscopy were consistent with those obtained by GC-MS at a confidence level of 95%. Without sample pretreatment, Raman spectroscopy method is simple to operate and more suitable for the rapid quantitative determination of 1, 2-propylene glycol and glycerol in batches of refill fluids for electronic cigarettes.