A fast clean-up method has been developed to purify maize extracts and to detect moniliformin (MON) in maize samples from North-West Italy over a four-year period (2008-2011). The method is based on the use of MycoSep® 240 Mon clean-up columns (Romer Labs®). Samples were extracted using acetonitrile/water (84:16, v/v), and the extracts were purified with previously described clean-up columns. The liquid chromatography-tandem mass spectrography (LC-MS/MS) analysis has been carried out by means of hydrophilic interaction chromatography (HILIC), combined with negative electrospray mass spectrometry. The method has a recovery of 76-91% (relative standard deviation, RSD%: 6-14%), a limit of detection (LOD) of 1 µg kg⁻¹ and a limit of quantification (LOQ) of 4 µg kg⁻¹. Naturally contaminated maize (108 samples) was analysed for MON content. The average percentages of positive samples was 93% with the following ranges (µg kg⁻¹): 33-2606 (2008); <LOD-527 (2009); <LOD-920 (2010); <LOD-409 (2011).