Leça, João M.Pereira, Ana C.Vieira, Ana C.Reis, Marco S.Marques, José C.2021-10-142021-10-142015Leça, J. M., Pereira, A. C., Vieira, A. C., Reis, M. S., & Marques, J. C. (2015). Optimal design of experiments applied to headspace solid phase microextraction for the quantification of vicinal diketones in beer through gas chromatography-mass spectrometric detection. Analytica chimica acta, 887, 101-110. https://doi.org/10.1016/j.aca.2015.06.044http://hdl.handle.net/10400.13/3727Vicinal diketones, namely diacetyl (DC) and pentanedione (PN), are compounds naturally found in beer that play a key role in the definition of its aroma. In lager beer, they are responsible for off-flavors (buttery flavor) and therefore their presence and quantification is of paramount importance to beer producers. Aiming at developing an accurate quantitative monitoring scheme to follow these off-flavor compounds during beer production and in the final product, the head space solid-phase microextraction (HS-SPME) analytical procedure was tuned through experiments planned in an optimal way and the final settings were fully validated. Optimal design of experiments (O-DOE) is a computational, statistically oriented approach for designing experiences that are most informative according to a well-defined criterion. This methodology was applied for HS-SPME optimization, leading to the following optimal extraction conditions for the quantification of VDK: use a CAR/PDMS fiber, 5 ml of samples in 20 ml vial, 5 min of pre-incubation time followed by 25 min of extraction at 30 C, with agitation. The validation of the final analytical methodology was performed using a matrix-matched calibration, in order to mini mize matrix effects. The following key features were obtained: linearity (R2 > 0.999, both for diacetyl and 2,3-pentanedione), high sensitivity (LOD of 0.92 mg L 1 and 2.80 mg L 1 , and LOQ of 3.30 mg L 1 and 10.01 mg L 1 , for diacetyl and 2,3-pentanedione, respectively), recoveries of approximately 100% and suitable precision (repeatability and reproducibility lower than 3% and 7.5%, respectively). The applicability of the methodology was fully confirmed through an independent analysis of several beer samples, with analyte concentrations ranging from 4 to 200 g L 1engVicinal diketonesHeadspace solid phase microextractionOptimizationOptimal design of experiments.Faculdade de Ciências da VidaEscola Superior de Tecnologias e GestãoFaculdade de Ciências Exatas e da Engenhariajournal article10.1016/j.aca.2015.06.044