Method development and validation for the determination of nicotine enantiomers in electronic cigarette liquids using reversed-phase and chiral phase High Performance Liquid Chromatography

A specific and sensitive High Performance Liquid Chromatography method has been developed for the determination of nicotine enantiomers in electronic cigarette liquids using reversed phase and chiral phase parameters. Separation of racemic nicotine was achieved using a Waters xTerra MS C8 column with a Methanol:Phosphate Buffer:Triethylamine (40:60:0.5) mobile phase and a detection wavelength set at 260nm. Chiral separation was achieved using a Daicel ChiralPak AD-H column with a Methanol:Ethanol:Triethylamine (90:10:0.1) mobile phase and a detection wavelength set at 260nm. Linearity was performed for both the racemic and chiral separation of nicotine over a range of 100 to 1000ppm. The correlation coefficients for both separations corresponded to 0.999. Accuracy testing was performed resulting in a percent recovery of 100.1% and a %RSD of 2.088 for the reversed phase separation and a percent recovery of 100.3% with a %RSD of 1.666 for the chiral separation. The precision for the reversed phase and chiral separations showed %RSD values of 1.748 and 1.682 respectively. Specificity of the reversed phase method was conducted by subjected a sample and placebo to forced degradation conditions for 24-hours. Based on the forced degradation results, nicotine showed optimal degradation with base hydrolysis and peroxide oxidation. Peak purity studies were performed for the optimal degradation standards with a peak purity greater than 990. Samples of electronic cigarette liquids were obtained from multiple online venders and though donations from Northeastern Illinois University students. The results showed a significant discrepancy between the labeled nicotine concentration and the amount determined though separation, with many samples containing double their label concentrations. The chiral separation method proved to only work for a faction of the companies tested. However, for samples where chiral separation could be achieved, the amount of R- and S-nicotine varied between samples.