title: Determination of pesticides in lettuce using solid-liquid extraction with low temperature partitioning.
abstract: This work describes the optimization and validation of a method employing solid-liquid extraction with low temperature partitioning (SLE/LTP) together with analysis by gas chromatography with electron capture detection (GC/ECD) for the determination of nine pesticides (chlorothalonil, methyl parathion, procymidone, endosulfan, iprodione, λ-cyhalothrin, permethrin, cypermethrin, and deltamethrin) in lettuce. The method was found to be selective, accurate, and precise, with means recovery values in the range of 72.3-103.2%, coefficients of variation ⩽ 12%, and detection limits in the range 0.4-37 μg kg(-1). The matrix components significantly influence the chromatographic response of the analytes (above 10%). The optimized and validated method was applied to determine the residual concentrations of the fungicides iprodione and procymidone that had been applied to field crops of lettuce. The maximum residual concentrations of the pesticides in the lettuce samples were 13.6 ± 0.4 mg kg(-1) (iprodione) and 1.00 ± 0.01 mg kg(-1) (procymidone), on the day after application of the products.
authors: Department of Chemistry, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
authors: Anna I G
authors: AI
authors: Costa
authors: Department of Chemistry, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil. Electronic address: meliana@ufv.br.
authors: Maria E L R
authors: ME
authors: Queiroz
authors: Department of Chemistry, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
authors: Antônio A
authors: AA
authors: Neves
authors: Department of Chemistry, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
authors: Flaviane A
authors: FA
authors: de Sousa
authors: Department of Phytopathology, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
authors: Laércio
authors: L
authors: Zambolim
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D018545:Lactuca / Q000737:chemistry*; D008743:Methyl Parathion / Q000032:analysis / Q000302:isolation & purification; D009570:Nitriles / Q000032:analysis / Q000302:isolation & purification; D010573:Pesticide Residues / Q000032:analysis / Q000302:isolation & purification*; D011722:Pyrethrins / Q000032:analysis / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods*; D013696:Temperature
chemical_list: D009570:Nitriles; D010573:Pesticide Residues; D011722:Pyrethrins; C017160:cypermethrin; C017180:decamethrin; D008743:Methyl Parathion; C037304:cyhalothrin
keywords: Chlorothalonil (PubChem CID: 15910); Cypermethrin (PubChem CID: 2912); Deltamethrin (PubChem CID: 40585); Endosulfan (PubChem CID: 3224); Gas chromatography; Iprodione (PubChem CID: 37517); Lettuce; Methyl parathion (PubChem CID: 4130); Permethrin (PubChem CID: 40326); Pesticides; Procymidone (PubChem CID: 36242); λ-Cyhalothrin (PubChem CID: 443046)