Abstract An improved method for determination of 2-dodecylcylobutanone (DCB) in irradiated ground beef patties was developed. This method is based on a head-space solid-phase microextraction (HS-SPME) technique followed by gas-chromatography–mass-spectrometry (GC/MS) detection. SPME conditions were optimised: time and temperature for the adsorption of DCB on the polydimethylsiloxane (PDMS) fiber were set at 60 min and 80 °C, respectively. A matrix-matched standard calibration in the range 5–150 ppb was carried out, using 2-pentylcyclopentanone as internal standard. Linearity (r2 = 0.9999), repeatability (8.4%), intermediate precision (13.6%), limit of detection (LOD) (1.5 ppb), lower limit of quantification (LLOQ) (5 ppb) demonstrated that the analytical procedure is fully reliable. The method was applied to irradiated samples in order to evaluate the dose–response effects. The concentration of DCB was quantified in beef patties irradiated at doses as low as 0.5 kGy and was linearly increased up to 8 kGy.