Dithiocarbamates are common fungicides widely used in agriculture. They are characterized by high chemical and biological activity that makes them suitable for the protection of more than 70 crops from approximately 400 pathogens. Following application, dithiocarbamates break down rapidly and residues can be found in the agriculture products.
In mammals dithiocarbamates typically show low acute toxicity, but after prolonged exposure and especially in presence of heavy metal ion in the molecule the toxicity of these compounds significantly increases. Dermatitis and even neurotoxic effects have been observed after long-term exposures.
For these reasons, in order to assure the food quality and healthy, an accurate control of dithiocarbamate residues in agriculture products is highly recommended. In 1998 the European Community produced the European Standard EN 12396-2 in which a method for the determination of dithiocarbamate residues in non-fatty foods is described: this method is based on the reaction with tin-(II)-chloride and hydrochloric acid with consequent release of CS2, which is then analyzed by gas chromatography coupled to electron capture or mass spectrometric detector. The CS2 amount is proportional to the concentration of fungicides.
In this work, a new approach is described for the determination of dithiocarbamate residues in fruit and vegetable samples according to the method EN 12396-2. This approach is based on the use of Static Headspace technique coupled to GC-TOF MS. The sample is heated and shaken in presence of HCl and SnCl2 into a closed headspace vial and, at the end of the incubation time, an aliquot of the headspace is automatically transferred to the GC-TOF MS system and for CS2 content analysis. SHS Static Headspace autosampler guarantees a complete automation in the sample preparation, while TOFMS assures a reliable identification of the target compounds thanks to the full mass spectrum acquisition and matching against NIST library.