title: Quantitative Detection of NADH Using a Novel Enzyme-Assisted Method Based on Surface-Enhanced Raman Scattering.
abstract: An enzymatic method for quantitative detection of the reduced form of nicotinamide-adenine dinucleotide (NADH) using surface-enhanced Raman scattering was developed. Under the action of NADH oxidase and horseradish peroxidase, NADH can generate hydrogen peroxide (H₂O₂) in a 1:1 molar ratio, and the H₂O₂ can oxidize a chromogen into pigment with a 1:1 molar ratio. Therefore, the concentration of NADH can be determined by detecting the generated pigment. In our experiments, eight chromogens were studied, and o-tolidine (OT) was selected because of the unique Raman peaks displayed by its corresponding pigment. The optimal OT concentration was 2 × 10-3M, and this gave the best linear relationship and the widest linear range between the logarithmic H₂O₂ concentration and the logarithmic integrated SERS intensity of the peak centered at 1448 cm-1. Under this condition, the limit of detection for NADH was as low as 4 × 10-7M. Two NADH samples with concentrations of 2 × 10-4and 2 × 10-5M were used to validate the linear relationship, and the logarithmic deviations were less than 3%.
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China. 15117955455@163.com.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Teng
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China. lvmy1991@163.com.
authors.forename: Mingyang
authors.initials: M
authors.lastname: Lv
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China. liuluo@mail.buct.edu.cn.
authors.forename: Luo
authors.initials: L
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China. zhxin@mail.buct.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China. ymzhao@semi.ac.cn.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Analytical and Testing Center, Beijing Normal University, Beijing 100875, China. wuzl@bnu.edu.cn.
authors.forename: Zhenglong
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China. hjxu@mail.buct.edu.cn.
authors.forename: Haijun
authors.initials: H
authors.lastname: Xu
keywords: NADH; enzyme-assisted; quantitative detection; surface enhanced Raman scattering