Thermo Fisher Scientific, Runcorn, UK Keywords: Gas chromatography, GC, flame ionization detection, FID, headspace, valve and loop, TriPlus 500 HS, GB 19083-2010, GBT 16886.7-2015, carcinogenic, ethylene oxide, face masks Goal To develop a fast, cost-effective analytical method suitable for the analysis of residual ethylene oxide and