Glycol‐based antifreeze liquids, commonly composed of ethylene glycol or propylene glycol, have important uses in automotive cooling, but they should be handled with care due to their toxicity. Ethylene glycol is highly toxic to humans and animals. A fast, accurate, precise, and robust method was developed for the simultaneous quantification of seven most important glycols and their isomers.MethodsGlycols were analyzed from diluted sample solution of coolants using gas chromatography coupled with mass spectrometry (GC–MC) in single ion monitoring mode.ResultsThe method was developed and validated for seven individual glycols (ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol). Limits of detection (1–2 μg/mL) and limits of quantification (10 μg/mL) obtained were appropriate. The present method was applied for the determination of glycols in 10 different antifreeze liquids commercially available on the Romanian market, proving to be reliable.ConclusionsA method that requires only a two‐step dilution of antifreeze samples combined with direct liquid injection GC–MS was validated for the simultaneous quantification of seven glycols (and their isomers) in 10 different types of antifreeze liquids. The results obtained in the validation procedure proved that the GC–MS method is sensitive and precise for the quantification of glycols.