Analysis of organic acetates in e-vapor products by GC-MS/MS
Organic acetates (methyl acetate, ethyl acetate, isobutyl acetate, isoamyl acetate and benzyl acetate) are flavorants and are of interest for E-vapor products testing based on recent guidance from FDA-CTP. A review of the literature shows few, if any, direct-application methods for these analytes. Herein we wish to present a GC-MS/MS method for the analysis of these acetates in e-vapor product aerosols and e-liquids. These organic compounds have a wide range of boiling points with methyl acetate being most volatile and ethyl acetate being the second. Since they can elute around the same retention time as the solvent, it is important to have the right solvent for GC separations. Various solvents have been tested and acetonitrile is most suitable which provides good separations from these volatile acetates. In addition, split injection (30:1) is applied in order to further ensure good separations. The calibration range is 20 to 2500 ng/mL for methyl acetate, 80 to 10000 ng/mL for ethyl acetate, 40 to 5000 ng/mL for isobutyl acetate and isoamyl acetate, and 8 to 1000 ng/mL for benzyl acetate. Furfural-d4 is used as internal standard for benzyl acetate, while ethyl-2,2,2-d3 acetate is used as internal standard for other four acetates. The LOQ of the method is defined as lowest spiking level during the validation which ranges from 8 – 80 ng/mL for various analytes above, or 3.2 – 32 ng/puff for 50 puffs of aerosols, or 0.44 – 4.4 µg/g for 0.36 g of e-liquids. The new method has been validated with good recoveries for e-vapor product aerosols (87 – 112 %) and e-liquids (79 – 124 %).