title: Quenching-Chemiluminescence Determination of Trace Amounts of l-Tyrosine Contained in Dietary Supplement by Chemiluminescence Reaction of an Iron-Phthalocyanine Complex.
abstract: The chemiluminescence (CL) signal immediately appeared when a hydrogen peroxide solution was injected into an iron-phthalocyanine tetrasulfonic acid (Fe-PTS) aqueous solution. Moreover, the CL intensity of Fe-PTS decreased by adding l-tyrosine. Based on these results, the determination of trace amounts of l-tyrosine was developed using the quenching-chemiluminescence. The calibration curve of l-tyrosine was obtained in the concentration range of 2.0 × 10(-7) M to 2.0 × 10(-5) M. Moreover, the relative standard deviation (RSD) was 1.63 % (n = 5) for 2.0 × 10(-6) M l-tyrosine, and its detection limits (3σ) were 1.81 × 10(-7) M. The spike and recovery experiments for l-tyrosine were performed using a soft drink. Furthermore, the determination of l-tyrosine was applied to supplements containing various kinds of amino acids. Each satisfactory relative recovery was obtained at 98 to 102%.
authors.affiliation: Department of Biomolecular Functional Engineering, Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Ohtomo
authors.forename: Shukuro
authors.initials: S
authors.lastname: Igarashi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Takagai
authors.forename: Osamu
authors.initials: O
authors.lastname: Ohno