title: Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy.
abstract: As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p=0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR.
authors.affiliation: School of Chinese Pharmacology, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Qu
authors.affiliation: School of Life Sciences, Beijing University of Chinese Medicine, Beijing 100029, China.
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Chen
authors.affiliation: School of Chinese Pharmacology, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Gui-Jun
authors.initials: GJ
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China. Electronic address: sunsq@tsinghua.edu.cn.
authors.forename: Su-Qin
authors.initials: SQ
authors.lastname: Sun
authors.affiliation: School of Chinese Pharmacology, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
mesh_terms: D002482:Cellulose / Q000737:chemistry; D004340:Drug Contamination; D008031:Lignin / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D029645:Thymelaeaceae / Q000737:chemistry*
chemical_list: D002482:Cellulose; D008031:Lignin
keywords: Adulteration screening; Aquilariae Lignum Resinatum; Correlation coefficient; Fourier transform infrared spectroscopy; Second derivative infrared spectroscopy; Two-dimensional correlation infrared spectroscopy