RT info:eu-repo/semantics/article T1 Ad-hoc blocked design for the robustness study in the determination of dichlobenil and 2,6-dichlorobenzamide in onions by programmed temperature vaporization-gas chromatography–mass spectrometry A1 Herrero Gutiérrez, Ana A1 Reguera Alonso, Celia A1 Ortiz Fernández, Mª Cruz A1 Sarabia Peinador, Luis Antonio A1 Sánchez Pastor, Mª Sagrario K1 Chemistry K1 Mathematics K1 Química K1 Matemáticas AB An ‘ad-hoc’ experimental design to handle the robustness study for the simultaneous determination of dichlobenil and its main metabolite (2,6-dichlorobenzamide) in onions by programmed temperature vaporization-gas chromatography-mass spectrometry (PTV-GC-MS) is performed. Eighteen experimental factors were considered; 7 related with the extraction and clean up step, 8 with the PTV injection step and 3 factors related with the derivatization step. Therefore, a high number of experiments must be carried out that cannot be conducted in one experimental session and, as a consequence, the experiments of the robustness study must be performed in several sessions or blocks. The procedure to obtain an experimental design suitable for this task works by simultaneously minimizing the joint confidence region for the coefficient estimates and the correlation among them and with the block. In this way, the effect of the factors is not aliased with the block avoiding possible misinterpretations of the effects of the experimental factors on the analytical responses. The developed experimental design is coupled to the PARAFAC2 method, which allows solving some specific problems in chromatography when working with complex matrix such as co-elution of interferents (including silylation artifacts from the derivatization step) and small shifts in the retention time and, besides, the unequivocal identification of the target compounds according to document SANCO/12571/2013. PB Elsevier YR 2014 FD 2014-11 LK http://hdl.handle.net/10259/4286 UL http://hdl.handle.net/10259/4286 LA eng NO Ministeriode Economía y Competitividad and Junta de Castilla y León underprojects CTQ2011-26022 and BU108A11-2, respectively. DS Repositorio Institucional de la Universidad de Burgos RD 26-abr-2024