There has been a trend by vendors of e-liquids to offer larger containers of e-liquids than in the past. Thus, it is possible that larger containers may be kept at ambient temperatures for several months or more. Therefore, we began an ageing study in October 2019 with four highly flavoured, high-glycerol e-liquids (all 6 mg/mL nicotine) in 120-mL bottles. The flavour descriptors on the labels and sample numbers were: 1) crunchy cookie and coconut; 2) blue raspberry and candy; 3) choco chip cookie and vanilla ice cream; and 4) cherry pie and custard. Samples were taken weekly through February 2020 with samples put in frozen storage each week. At the end of six months, samples of each e-liquid and their frozen controls were sent to an ISO 17025 accredited laboratory for cytotoxicity assays by the neutral red uptake (NRU) method. No differences were reported. Shortly thereafter, the study was suspended due to Covid-19 restrictions. The frozen samples that had been taken weekly since the first sampling were kept frozen, and the remaining samples in the 120-mL bottles were kept at ambient temperature. Samples of both frozen and ambient aged e-liquids were dissolved in methanol at 1 % (w/v) and 10 % (w/v) concentrations. Initial analyses were done on a Cogent Bidentate C18 column (250 × 4.6 mm) with a mobile phase of 25 % acetonitrile and 75 % water at a flow rate of 1 mL/min with UV detection at 280 nm. Based on the chromatograms obtained under those analytical conditions, Samples 3 and 4 were the most stable. Sample 2 was the least stable, showing apparent chemical reactions between the ethyl maltol and other components of the e-liquid. Sample 1 showed loss of early eluting peaks as well as what may have been reactions of the propylene glycol acetals of aromatic aldehydes with glycerol.