title: Standard infrared absorption spectrum of betaine and optimal conditions for its measurement.
abstract: The infrared absorption (IR) spectrum is often used as a standard reference in identification tests of food additives in Japan. In the case of betaine, many different IR spectra have been reported and, therefore, it is necessary to establish an IR spectrum that is reproducible and reliable enough to be used as a standard for identification. In the present study, suitable conditions to obtain a standard IR spectrum were examined from various viewpoints, including pretreatment, selection of method, and measuring technique. The KBr disk method, which has generally been used to identify betaine, was found to be humidity-dependent, and there was also an interaction between betaine and KBr. A reproducible IR spectrum suitable as a standard could be obtained by drying betaine at 105 degrees C for 3 hours over phosphorus pentoxide, and then measuring the IR spectrum by the liquid paraffin (Nujol) paste method.
authors.affiliation: Department of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan.
authors.forename: Youji
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Madok
authors.initials: M
authors.lastname: Saito
authors.forename: Masaki
authors.initials: M
authors.lastname: Mifune
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Saito
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sato
authors.forename: Chikako
authors.initials: C
authors.lastname: Yomota
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tanamoto
mesh_terms: D001622:Betaine / Q000032:analysis*; D012015:Reference Standards; D013055:Spectrophotometry, Infrared / Q000592:standards*
chemical_list: D001622:Betaine