title: Direct Analysis of Lipophilic Antioxidants of Olive Oils Using Bicontinuous Microemulsions.
abstract: Quantitative analyses of olive oil for lipophilic antioxidants, such as α-tocopherol and phenolics, by simple electrochemical measurements were conducted in a bicontinuous microemulsion (BME), which was bicontinuously composed of saline and toluene microphases with a surfactant system. Lipophilic antioxidants in oils were directly monitored in BME solutions using a lipophilic, fluorinated nanocarbon-film electrode (F-ECR). The combination of a well-balanced BME and extremely biased electrodes, such as strongly hydrophilic indium/tin oxide and strongly lipophilic (hydrophobic) F-ECR, allowed individual monitoring of hydrophilic and lipophilic antioxidants in the same BME solution without any required extraction. Furthermore, values for the charge Q, integrated from observed currents, showed good linear relationships with the results of conventional assays for antioxidant activity, namely, total phenolics and oxygen radical absorbance capacity assays, even with practical food samples. This proposed methodology provided a very simple, rapid, easily serviceable, and highly reproducible analysis that possesses great potential for applications to a wide range of chemical mixtures, in terms of analyte and media, beyond food oils.
authors.affiliation: Science and Technology Division, Okinawa National College of Technology , 905 Henoko, Nago, Okinawa 905-2192, Japan.|Graduate School of Science and Technology, Kumamoto University , 2-39-1 Kurokami, Kumamoto, Kumamoto 860-8555, Japan.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Kuraya
authors.affiliation: Graduate School of Science and Technology, Kumamoto University , 2-39-1 Kurokami, Kumamoto, Kumamoto 860-8555, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Nagatomo
authors.affiliation: Graduate School of Science and Technology, Kumamoto University , 2-39-1 Kurokami, Kumamoto, Kumamoto 860-8555, Japan.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Sakata
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Kato
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Niwa
authors.affiliation: Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem), Itopia Hashimoto Building 7F, 2-11-9 Iwamoto-cho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Taisei
authors.initials: T
authors.lastname: Nishimi
authors.affiliation: Graduate School of Science and Technology, Kumamoto University , 2-39-1 Kurokami, Kumamoto, Kumamoto 860-8555, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kunitake
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry*; D004566:Electrodes; D004655:Emulsions / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D000069463:Olive Oil / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D004655:Emulsions; D000069463:Olive Oil