## 1 Introduction  
Mycotoxins are low-molecular-weight natural products, very diverse in terms of structure and abilities, produced as secondary metabolites by fungi. Pattulin (PAT) is an important mycotoxin produced by over 30 genera of mold such as Penicillin, Aspergillus, and Byssochlamys. In particular, _Penicillium expansum_ is recognized as the main source of PAT and it has been commonly associated with apple rot [1]. These molds grow easily in damaged fruit or in derived products such as juices, if storage conditions are deficient. Some of the most serious health effects of PAT ingestion in humans are agitation, convulsions, edema, intestinal ulceration, inflammation and vomiting [2]. The toxicity of these molecules has led to the set-up of strict regulations in many countries for their control in food and feed, and the consequent establishment of official legislation. The establishment of maximum limits in some food products resulted in an increasing demand of sensitive, selective and effective analytical methods. The European Commission Regulation (EC) 1881/2006 established a maximum content for PAT of 10 ppb in infant fruit juices, 50 ppb for fruit juices for adults and 25 ppb in fruit-derived products [3].  
For the determination of PAT, thin layer chromatography was firstly used. Nowadays, the official analytical method adopted by the Association of Official Analytical Chemists (AOAC) for the analysis of PAT in food is high performance liquid chromatography (HPLC) with ultraviolet (UV) detection,using an extraction with ethyl acetate and clean-up with sodium carbonate [4]. The main drawback of UV detection is the poor resolution between PAT and other co-extracted compounds such as hydroxymethylfurfural. To overcome this interference, liquid chromatography may be combined with mass spectrometric determination [1]. As an additional problem, PAT is vulnerable to the alkaline conditions of the previously mentioned extraction method. Purification by solid-phase extraction (SPE) has been frequently applied as an alternative procedure [5]. In the last years, molecularly imprinted polymers (MIPs) started to be used, and are becoming promising materials for extracting different analytes present in food and beverages [6]. However, mycotoxins are usually too toxic or too expensive to be used as template molecules in MIP preparation. Template bleeding may be an additional problem of these polymers, especially when dealing with very low detection levels. To overcome these limitations, dummy templates can be applied during MIP synthesis [7]. Also, magnetic materials can provide fast and simple methods of extraction and have already demonstrated their effectiveness to extract patulin [8].  
In the present work, a rapid and selective method based on an in-house designed magnetic molecularly imprinted stir-bar (MMISB) has been developed for the isolation of PAT. For MIP synthesis, a structural analogue of PAT, 2-oxindole, was used as a dummy template (Figure 1) [9]. The molecularly imprinted polymer was grafted on the silanized surface of a glass-covered stir-bar using an adaptation of typical protocols used in grafting techniques. The applicability of this novel stirring bar for the extraction of PAT has been tested in spiked apple samples using HPLC-MS/MS for detection.