Multivariate optimization for extraction of 2-methylimidazole and 4-methylimidazole from açaí-based food products
Luis Eduardo Silva Nascimento1, Bhawana Thapa2, Wellington da Silva Oliveira3
1Department of Food Science and Nutrition, School of Food Engineering, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil; Department of Chemistry, Iowa State University, 2415 Osborn Drive, Ames, IA 50011, USA.
Abstract:
In this study, polymeric ionic liquids featuring different functional moieties were applied as sorbent coatings in direct-immersion solid-phase microextraction (DI-SPME) for the extraction of 2-methylimidazole (2-MI) and 4-methylimidazole (4-MI) from açaí-based food products followed by gas chromatography-mass spectrometry (GC-MS) analysis. The analytical method was optimized using a sequential experimental design. Variables used in GC-MS such as desorption time, as well as for SPME-DI, including extraction time, extraction temperature, incubation time of extraction, amount of NaCl in the extract, and stirring rate, were optimized. The fitness-for-purpose of the method was verified by the linearity of matrix-matched calibration curves (R2 ≥ 0.9921), adequate recoveries (81.7-89.7 %), and precision (relative standard deviations ≤11.2 %). The method was applied to twenty-five samples of açaí-based food products. 4-MI was found in four samples whereas 2-MI was not detected above the limit of detection. The method was found to be suitable for quality control analysis.
