Microwave/SPME method to quantify pesticide residues in tomato fruits |
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Authors: | Valérie Guillet Céline Fave Michel Montury |
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Institution: | 1. Laboratoire de Physico- et Toxico-Chimie , Institut des Sciences Moléculaires , Périgueux Cedex, France;2. Association Interrégionale de Recherche et d'Expérimentation Légumière (AIREL) , Sainte-Livrade/Lot, France |
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Abstract: | A new analytical method using focused microwave-assisted extraction (FMAE), coupled with solid phase micro-extraction (SPME), has been elaborated to determine 25 pesticides used in tomato cultivation. Microwave energy was used for a fast and controlled heating of solvent to selectively extract compounds. Calibration curves were plotted from blank tomato samples spiked at different concentrations with standards. A linear response was obtained between 10 and 1000 μ g/Kg for pyrethroids and between 0.1 and 5000 μ g/Kg for other compounds. For all studied substances, the resulting correlation coefficient (r2) was greater than 0.99. Limits of detection (LOD) and quantification (LOQ) were measured lower than 8 and 25 μ g/Kg, respectively. The relative standard deviation (RSD) was determined below 15% for all pesticides. Field incurred tomato samples were used to validate the new FMAE/SPME method. Observed analysis results by using this technique were in good agreement compared to those obtained by two accredited trading laboratories using traditional methods. Four tomato samples, bought in a local market, were also tested with the FMAE/SPME method. |
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Keywords: | Food analysis microwave extraction solid phase micro-extraction pesticides pyrethroids |
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