Abstract Residual water in non-aqueous solvents can cause measurable changes in electrochemical experiments. Such levels can be difficult to detect quantitatively. We report the development of a new method to detect trace amounts of water in non-aqueous solvents such as propylene carbonate. Water is specifically labelled by derivatization with hexafluoroacetone and determined by capillary gas chromatography with electron capture detection. In propylene carbonate, water can be detected at levels above 500 ppb and determined quantitatively to a limit of 5 ppm. In hexane and ethyl acetate, detection limits are 50 ppb. In addition to low detection limits, the analysis is as much as ten times faster and uses four to ten times less sample than conventional packed column chromatography.