Monitoring pesticide residues in greenhouse tomato by combining acetonitrile-based extraction with dispersive liquid–liquid microextraction followed by gas-chromatography–mass spectrometry

• Published in: Food chemistry 2012-12, Vol.135 (3), p.1071-1077
• Main Authors: Melo, Armindo, Cunha, Sara C., Mansilha, Catarina, Aguiar, Ana, Pinho, Olívia, Ferreira, Isabel M.P.L.V.O.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Dispersive liquid–liquid microextraction; Food Contamination - analysis; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry - methods; Gas chromatography–mass detection; General aspects; Greenhouses; Improved extraction procedure; Liquid Phase Microextraction - methods; Lycopersicon esculentum; Lycopersicon esculentum - chemistry; Methods of analysis, processing and quality control, regulation, standards; Pesticide Residues - analysis; Pesticide Residues - isolation & purification; Pesticides; Tomato
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2012.05.112

► Multiclass and multiresidue analyses of pesticide residues in greenhouses tomato. ► DLLME was performed using acetonitrile QuEChERS extracts as dispersive solvent. ► Validated method enables analyzes of a large number of samples within a working day. ► Cyprodinil was quantified in a tomato sample. ► Azoxystrobin, fenhexanid, tolyfluanid, λ-cyhalothrin and trifloxystrobin were detected. A multiclass and multiresidue method for pesticide analysis in tomato was validated. Extraction and pre-concentration of the pesticide residues from acetonitrile extracts was performed by using dispersive liquid–liquid microextraction (DLLME) technique, followed by gas chromatography–mass detection. DLLME was performed using carbon tetrachloride as extractive solvent and acetonitrile extract as dispersive solvent, in order to increase enrichment factor of the extraction procedure. Validation parameters indicated the suitability of the method for routine analyses of thirty pesticides in a large number of samples. In general, pesticide recoveries ranged between 70% and 110% and repeatability ranged between 1% and 20%. The proposed method was applied to the monitoring of pesticides in tomatoes grown during winter in greenhouses. Among the compounds considered in this work, cyprodinil was found in tomato at concentrations of 0.33mg/kg, other pesticides like azoxystrobin, fenhexanid, tolyfluanid, λ-cyhalothrin and trifloxystrobin were also detected, but, not quantified.