Simultaneous Determination of Melatonin, l-Tryptophan, and two l-Tryptophan-Derived Esters in Food by HPLC with Graphene Oxide/SiO2 Nanocomposite as the Adsorbent

• Published in: Food analytical methods 2018-09, Vol.11 (9), p.2438-2446
• Main Authors: Niu, Jiahua, Zhang, Xiaoting, Qin, Peige, Yang, Yixin, Tian, Shufang, Yang, Hui, Lu, Minghua
• Format: Article
• Language: English
• Subjects: Adsorbents; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cost analysis; Desorption; Detection limits; Esters; Food; Food Science; Fourier transforms; Graphene; High performance liquid chromatography; Infrared spectroscopy; Liquid chromatography; Melatonin; Microbiology; Microscopy; Morphology; Nanocomposites; Scanning electron microscopy; Silicon dioxide; Sol-gel processes; Transmission electron microscopy; Tryptophan; X-ray diffraction
• ISSN: 1936-9751; 1936-976X
• DOI: 10.1007/s12161-018-1213-2

In this research, a dispersive solid-phase extraction (dSPE) with graphene oxide@SiO 2 (GO@SiO 2 ) nanocomposites as the adsorbent followed by high-performance liquid chromatography analysis was developed for simultaneous determination of melatonin, l -tryptophan, and two l -tryptophan-derived esters in food (black sesame seed ( Sesamum indicum L. ) was selected in this case). The GO@SiO 2 nanocomposite was prepared by one-pot aggregation in aqueous phase with sol-gel technique. The structure and morphology of the GO@SiO 2 were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffraction. The extraction conditions of dSPE including the ratio of material to liquid, adsorption and desorption time, desorption temperature, and desorption solvents were investigated, respectively. The detection limits of the developed method for the analysis of melatonin, l -tryptophan, l -tryptophan methyl ester, and l -tryptophan ethyl ester were achieved below 0.1 μg mL −1 . The established method was successfully applied to the analysis of the target analytes in black sesame seed, which provided a simple, low-cost, and sensitive approach for the determination of trace compounds in complex samples.