Surface-Enhanced Raman Spectroscopic Investigation of PAHs at a Fe3O4@GO@Ag@PDA Composite Substrates

Junyu Liu; Wencan Cui; Shihua Sang; Liang Guan; Kecheng Gu; Yinyin Wang; Jian Wang

doi:10.3390/mi13081253

Surface-Enhanced Raman Spectroscopic Investigation of PAHs at a Fe₃O₄@GO@Ag@PDA Composite Substrates

Micromachines (Basel). 2022 Aug 4;13(8):1253. doi: 10.3390/mi13081253.

Authors

Junyu Liu^{1

2}, Wencan Cui³, Shihua Sang¹, Liang Guan², Kecheng Gu², Yinyin Wang², Jian Wang²

Affiliations

¹ College of Material and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China.
² Department of Petroleum, Oil and Lubricants Army Logistics Academy of PLA, Chongqing 401331, China.
³ Department of Basic Courses, Army Logistic Academy of PLA, Chongqing 401331, China.

Abstract

A method for surface-enhanced Raman spectroscopy (SERS) sensing of polycyclic aromatic hydrocarbons (PAHs) is reported. Fe₃O₄@PDA@Ag@GO is developed as the SERS substrate prepared by classical electrostatic attraction method based on the enrichment of organic compounds by graphene oxide (GO) and polydopamine (PDA) and the good separation and enrichment function of Fe₃O₄. The morphology and structure of the SERS substrate were represented by transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and the UV-visible absorption spectrum (UV-vis spectra). The effect of different temperatures on SERS during synthesis was investigated, and it was found that the best effect was achieved when the synthesis temperature was 90 °C. The effect of each component of Fe₃O₄@PDA@Ag@GO nanocomposites on SERS was explored, and it was found that Ag NPs are of great significance to enhance the Raman signal based on the electromagnetic enhancement mechanism; apart from enriching the polycyclic aromatic hydrocarbons (PAHs) through π-π interaction, GO also generates strong chemical enhancement to the Raman signal, and PDA can prevent Ag from shedding and agglomeration. The existence of Fe₃O₄ is favored for the fast separation of substrate from the solutions, which greatly simplifies the detection procedure and facilitates the cycle use of the substrate. The experimental procedure is simplified, and the substrate is reused easily. Three kinds of PAHs (phenanthrene, pyrene and benzanthene) are employed as probe molecules to verify the performance of the composite SERS substrate. The results show that the limit of detection (LOD) of phenanthrene pyrene and benzanthene detected by Fe₃O₄@PDA@Ag@GO composite substrate are 10^-8 g/L (5.6 × 10^-11 mol/L), 10^-7 g/L (4.9 × 10^-10 mol/L) and 10^-7 g/L (4.4 × 10^-10 mol/L), respectively, which is much lower than that of ordinary Raman, and it is promising for its application in the enrichment detection of trace PAHs in the environment.

Keywords: Ag; PAHs; composite substrate; enrichment detection; surface-enhanced Raman spectroscopy.

Grants and funding

This research was supported by the Science and technology research project of Chongqing Education Commission in China (No. KJQN202012907), Natural Science Foundation of Chongqing in China (No. cstc2020jcyj-msxmX0274).