Determination of pesticides and mycotoxins in feed: Applicability of an analytical method in routine analysis

• Autores: Magni, Florencia Valentina; Michlig, Nicolás; Demonte, Luisina Delma; Michlig, Melina Paola; Repetti, María Rosa
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: FEED; PESTICIDE; ON-GOING VALIDATION
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

In routine analysis it is often necessary to introduce minor changes in protocols or extend the applicability of previously validated methods to similar matrices. The SANTE guidelines contemplate on-going validation as a quality control process to verify analytical performance through a reduced number of experiments1.In this work, a validated QuEChERS method for the determination of pesticides and mycotoxins in corn and alfalfa was used for the analysis of a large number of different types of feed samples (cereals, pastures, silages). Briefly, 2 g of sample were hydrated with 10 ml H2O (2% CH2O2), followed by extraction and partition with 10 ml acetonitrile, MgSO4/NaCl (4:1). An aliquot of the extract was then cleaned-up using d-SPE with MgSO4, C18 and PSA, prior to analysis by UHPLC-MS/MS2.A modification of the clean-up step had to be introduced due to the large number of samples to be processed and availability of sorbent salts at the time of analysis. Thus, for cereal-based samples only MgSO4/C18 was used while MgSO4/PSA was used for pasture-based samples.Following the concepts of the on-going validation, the mean recovery (Rec%) was evaluated at the same concentration level from validation (100 µg/kg). Precision was evaluated as repeatability and intermediate precision, repeating the test 2 and 3 consecutive days for corn and alfalfa, respectively. The recovery results obtained after the modifications were compared with those from the initial validation through statistical t-tests. Finally, an additional quality control test was done by applying the methodology to a European Union Proficiency Test (EUPT CF18-2014) in wheat flour.As a result, 80% of the studied compounds (117 pesticides and 2 mycotoxins) showed recoveries in the 60-140% range accepted for routine analysis by the SANTE guide, with RSDs <20% in both matrices.From the statistical tests, the Rec% of more than 85% of the studied compounds were not affected by the changes introduced. Moreover, for compounds such as acephate, chlorpyriphos methyl, clethodim, fenthion and metribuzin in corn, and methomyl, metribuzin, thiabendazole, profenofos, spinosad D and terbuphos in alfalfa their Rec% improved with respect to the initial validation. Finally, the results from the EUPT test were compared to the declared concentration through a z-score, verifying the aptitude of the method for the determination of azoxystrobin, epoxiconazole, linuron,pyraclostrobin and carbendazim.
Fil: Magni, Florencia Valentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina
Fil: Michlig, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina
Fil: Demonte, Luisina Delma. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina
Fil: Michlig, Melina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina
Fil: Repetti, María Rosa. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina
8th Latin American Pesticide Residue Workshop
Panamá
Panamá
Sociedad Latinoamericana sobre Residuos de Plaguicidas
Universidad Nacional del Litoral
Gobierno de la República de Panamá. Ministerio de Desarrollo Agropecuario