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Sociedade Brasileira de Espectrometria de Massas – BrMASS
GC-MS & LC-MS
MOLECULARLY IMPRINTED SOLID PHASE MICRO EXTRACTION OF TRIAZOLE PESTICIDES AND ANALYSIS BY GAS CHROMATOGRAPHY MASS SPECTROMETRY
André C. Vieira, João A. F. R. Mendonça, Eduardo C. Figueiredo*
Laboratory of Toxicant and Drug Analysis - LATF, Gabriel Monteiro da Silva St. 700, Federal University of Alfenas - Unifal-MG, 37130-000 Alfenas, MG, Brazil
Triazoles fungicides are an important classes of pesticides widely used in agriculture. Due to their characteristics such as high chemical stability and low biodegradability, these compounds can persist in environment, resulting in toxicological problems. So, several methods have been developed for the monitoring of triazoles in environmental matrices, mainly in water sample. In this way, we proposed, in this work, an alternative procedure to analyze triazoles in water samples based on molecularly imprinted solid phase microextraction following by GC-MS analysis. For the synthesis, a solution of 0.05 mmol de triadimenol, 0.2 mmol de methacrylic acid, 1.0 mmol de ethylene glycol dimethacrylate, 0.015 mmol de 2,2′-azobisisobutyronitrile and 0.5 mL de chloroform were purged with nitrogen and introduced into the glass tube of 0.53 (i.d.) x 100 mm in size. The tube was sealed and immersed in water-bath at 60ºC for 24 h. After the polymerization, the glass tube was broken, the monolith was removed, washed and used as fiber in a molecularly imprinted solid phase microextraction of triadimenol (m/z 112, 168, 128), tebuconazole (m/z 125, 70, 250), epoxiconazole (m/z 192, 165 and 138) and metconazole (m/z 250, 125, 145). Initially, during a conditioning step, the fiber was immersed in a methanol:acetic acid solution 90:10-v/v for 5 min. After this, the fiber was cleaned with water and inserted in the standard/sample during 7 min for the triazoles extraction. Then, the fiber was inserted in a GC-MS (model QP2010 - Shimadzu®, Tokyo, equipped with RTX 5 MS, 0.25 µm x 0.25 mm x 30 m) and the analytes were desorbed and analyzed. The stirring rate, extraction temperature, salting out effect, extraction time and sample volume were appraised by using univariate studies and the optimized conditions were 600 rpm, 45oC, 0.1 g of NaCl, 7 min and 10 mL, respectively. The procedure is simple and with low solvent consumption. The authors thank Unifal-MG, FAPEMIG (projects CDS-APQ-01612-10 and CDS-APQ-01323-09) and CNPq for the financial support.
4º Congresso BrMass – 10 a 13 de Dezembro de 2011