title: Isolation and Quantification of Polyamide Cyclic Oligomers in Kitchen Utensils and Their Migration into Various Food Simulants.
abstract: Small amounts of cyclic monomers and oligomers are present in polyamide (PA)-based kitchen utensils. In this study, we isolated eight PA-based cyclic monomers and oligomers from kitchen utensils made from PA6 (a polymer of ε-caprolactam) and PA66 (a polymer of 1,6-diaminohexane and adipic acid). Their structures were identified using high-resolution mass spectrometry and 1H- and 13C-nuclear magnetic resonance spectroscopy, and their residual levels in PA-based kitchen utensils and degree of migration into food simulants were quantified by high-performance liquid chromatography/mass spectrometry using purchased PA6 monomer and isolated PA66 monomers, and isolated PA6 and PA66 oligomers as calibration standards. Their total residual levels among 23 PA-based kitchen utensils made from PA6, PA66, and copolymers of PA6 and PA66 (PA6/66) ranged from 7.8 to 20 mg/g. Using water, 20% ethanol, and olive oil as food simulants, the total migration levels of the PA monomers and oligomers ranged from 0.66 to 100 μg/cm2 under most examined conditions. However, the total migration levels of the PA66 monomer and oligomers from PA66 and PA6/66 kitchen utensils into 20% ethanol at 95°C were very high (1,700 and 2,200 μg/cm2, respectively) due to swelling by high-temperature ethanol.
authors.affiliation: National Institute of Health Sciences, Kamiyoga, Setagaya-ku, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Abe
authors.affiliation: National Institute of Health Sciences, Kamiyoga, Setagaya-ku, Tokyo, Japan.
authors.forename: Motoh
authors.initials: M
authors.lastname: Mutsuga
authors.affiliation: Nagoya City Public Health Research Institute, Hagiyama-cho, Mizuho-ku, Nagoya, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohno
authors.affiliation: National Institute of Health Sciences, Kamiyoga, Setagaya-ku, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawamura
authors.affiliation: National Institute of Health Sciences, Kamiyoga, Setagaya-ku, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akiyama
mesh_terms: D002209:Caprolactam / Q000737:chemistry; D002853:Chromatography, Liquid; D003297:Cooking and Eating Utensils; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D009757:Nylons / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D009757:Nylons; D011108:Polymers; D002209:Caprolactam