SUMMARY
The Argentinean citrus agro-industry is a huge importance activity in the national and regional economy. Production, packaging, transport, cold treatment and concentrate juice production, essential oils, etc., are included. The controls and strategies on pesticide residues are increasing because of world importer markets and consumers of fresh or industrialized products requirements. Among the wide range of pesticides commonly used in citrus production, benzimidazoles are an important group of fungicides used for the control and treatment of diseases. The control of these fungicides residues are an important quality parameter when the fruits are going to be used for fresh consumption and for industrialization. The objective of this thesis is to develop alternative methodologies for determination of benzimidazoles pesticides in citrus, avoiding traditional ones that are generally of high cost, complex and high time analysis. The development of analytical methods for determination of thiophanate, thiabendazole and thiophanate methyl by solid phase microextraction and gas chromatography with nitrogen-phosphorus detector in fruits, concentrate juice and fermented products, and the determination of thiabendazole and carbendazim by solid phase extraction and high resolution liquid chromatography with diode array detector in essential oils, were proposed. In the first case, a carbowax / dvinilbencene polymer coating fiber was used with the following conditions: 10 minutes extraction with magnetic stirring at 2000 rpm and 50ml of pH 7 sample. Total mass absorbed at an equilibrium time of 720 minutes, the distribution constants and diffusion coefficients of the analytes in standard solutions and spiked samples were determined. The method was linear, precise, with high accuracy and sensitivity. The limits of quantification were 0.20 to 0.30 ppb for thiophanate methyl, 0.18 to 0.26 ppb for thiophanate and 0.09-0.17 ppb for thiabendazole, and recovery percentages between 95 and 98% for different analytes and matrices. The calibration curves for unknown samples analysis were made with spiked samples because of the presence of matrix effect. Extracted analytes were identified by gas chromatography - mass spectrometry. The methodology was applied to packaging house and concentrated juice samples showing good reproducibility and compatibility with traceability data provided. Carbendazim and thiabendazole determination in essential oils were optimized using a solid phase extraction with diol as an adsorbent and mobile phase consisting of acetonitrile / methanol (40:60, v/v), 5mM KPO4H2, acidified to 0.01% with acetic acid as eluents. The selected wavelengths were 303 and 285 nm for thiabendazole and carbendazim respectively. The method was linear, precise, with high accuracy and sensitivity.The limits of quantification were 58 and 68 ppb for thiabendazole and 68 and 75 ppb for carbendazim in standard solutions and spiked samples, respectively. The recovery percentages were 91 – 94% for thiabendazole and 96 – 98% for carbendazim. The calibration curves for unknown samples analysis were made with spiked samples because of the presence of matrix effect. The methodology was applied to essential oils samples showing good reproducibility and compatibility with traceability data provided related with residues of the processed fruits. The developed methodologies give to the citrus productive sector an important tool for problems controlling associated with production, manufacturing and marketing of this products, with high feasibility of transferring the results to the media.