title: Comparison of disposable pipette extraction and dispersive solid-phase extraction in the QuEChERS method for analysis of pesticides in strawberries.
abstract: In this study, we sought to assess the applicability of GC-MS/MS for the identification and quantification of 36 pesticides in strawberry from integrated pest management (IPM) and organic farming (OF). Citrate versions of QuEChERS (quick, easy, cheap, effective, rugged and safe) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for cleanup were compared for pesticide extraction. For cleanup, a combination of MgSO4, primary secondary amine and C18 was used for both the versions. Significant differences were observed in recovery results between the two sample preparation versions (DPX and d-SPE). Overall, 86% of the pesticides achieved recoveries (three spiking levels 10, 50 and 200 µg/kg) in the range of 70-120%, with <13% RSD. The matrix effects were also evaluated in both the versions and in strawberries from different crop types. Although not evidencing significant differences between the two methodologies were observed, however, the DPX cleanup proved to be a faster technique and easy to execute. The results indicate that QuEChERS with d-SPE and DPX and GC-MS/MS analysis achieved reliable quantification and identification of 36 pesticide residues in strawberries from OF and IPM.
authors.affiliation: REQUIMTE, Instituto Superior de Engenharia, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal CIQ-Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
authors.forename: Virgínia C
authors.initials: VC
authors.lastname: Fernandes
authors.affiliation: REQUIMTE, Instituto Superior de Engenharia, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal vfd@isep.ipp.
authors.forename: Valentina F
authors.initials: VF
authors.lastname: Domingues
authors.affiliation: CIQ-Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.affiliation: REQUIMTE, Instituto Superior de Engenharia, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Delerue-Matos