title: Ultra-sensitive HPLC-photochemical reaction-luminol chemiluminescence method for the measurement of secondary amines after nitrosation.
abstract: A novel method for the determination of secondary amines at the nanomolar level was developed. The method is based on the nitrosation reaction of secondary amines, with the generated N-nitrosamines being measured using an HPLC separation, photochemical reaction, and chemiluminescence detection system. The efficient nitrosation of secondary amines was performed using sodium nitrite (200 mM) and acetic acid (0.8 M) at 80 °C over 60 min. Although compounds bearing OH and SH functional groups also underwent the nitrosation reaction, the sensitivity of these compounds was 1000 times lower than that of the secondary amines. Our method was applied to the determination of low molecular weight secondary amines, including dimethylamine, morpholine, pyrrolidine, diethylamine, and piperidine, giving method detection limits of 0.7 nM, 0.2 nM, 0.4 nM, 0.7 nM, and 1.5 nM, respectively. The calibration curves were linear in the range of 5-100 nM. We then applied this method for the detection and quantification of these secondary amines in samples of tap water, river water, treated wastewater, and sea water. Dimethylamine was detected at concentrations up to 15.4 nM, <0.7 nM, and 48.5 nM in tap water, river water, and treated wastewater samples, respectively, with recoveries ranging from 94 to 103%. Other amines were also detected at nanomolar levels. These results indicate that our proposed method can be applied to the analysis of secondary amines in various environmental water samples. To the best of our knowledge, the proposed method is one of the most sensitive and selective methods for the determination of secondary amines without pre-concentration steps.
authors.affiliation: Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan. Electronic address: kodama@sci.kagoshima-u.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kodamatani
authors.affiliation: Department of Human Environmental Science, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada, Kobe 657-8501, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Iwaya
authors.affiliation: Department of Human Environmental Science, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada, Kobe 657-8501, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Saga
authors.affiliation: Department of Human Environmental Science, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada, Kobe 657-8501, Japan.
authors.forename: Keiitsu
authors.initials: K
authors.lastname: Saito
authors.affiliation: Water and Environmental Engineering, Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujioka
authors.affiliation: Department of Applied Science, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kanzaki
authors.affiliation: Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tomiyasu
keywords: Chemiluminescence; Luminol; N-nitrosamine; Nitrosation; Photochemical reaction; Secondary amine