Location of TEMPO derivatives in micelles: subtle effect of the probe orientation

卷:192

Aliaga, Carolina ; Bravo-Moraga, Felipe ; Gonzalez-Nilo, Danilo ; Marquez, Sebastian ; Luehr, Susan ; Mena, Geraldine ; Caroli Rezende, Marcos

Univ Santiago Chile

关键词: Partition constants;    4-AcyloxyTEMPO;    Reduced Triton X-100 micelle;    EPR g-factor;    Molecular dynamics simulation;   

DOI  :  10.1016/j.foodchem.2015.07.036

学科分类：食品科学和技术

【 摘 要 】

Partition coefficients for six 4-substituted derivatives of the 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) derivatives in aqueous solutions of reduced Triton X-100 (RTX-100) were determined by measurements of the probe EPR g-factor and of the fluorescence quenching of pyrene by the radical in the micelle. The partition constant attained a maximum value and then decreased with increasing probe hydrophobicity. Simulation of the probes inside the micelle showed that this trend could be rationalized by a change in the orientation of the 4-substituted TEMPO derivatives with the increasing substituent. chain-length. The use of the EPR g-factor for the determination of partition constants of radicals in micellar systems was thus validated as a reliable and sensitive method, capable of describing the probe orientation in its microenvironment. (C) 2015 Elsevier Ltd. All rights reserved.