Ratiometric SERS detection of polycyclic aromatic hydrocarbons assisted by β-cyclodextrin-modified gold nanoparticles.

Abstract

A surface-enhanced Raman scattering (SERS) method is described for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in the environment efficiently and economically. Detection sensitivity is improved by modifying gold nanoparticles (AuNPs) with 4-mercaptophenylboronic acid (4-MPBA) conjugated toβ-cyclodextrin (β-CD) as a new method for ratiometric determination of PAHs in solution. Pyrene (with a Raman band at 580cm-1) and anthracene (750cm-1) were used as the model analytes, while 4-MPBA (1570cm-1) was used as the internal reference to normalize the SERS signals. The intensity ratios of pyrene/4-MPBA increase linearly in the 2 to 10nM pyrene concentration range, and the intensity ratios of anthracene/4-MPBA increase linearly in the 10 to 100nM anthracene concentration range. The detection limits are 0.4nM for pyrene and 4.4nM for anthracene. This method was applied to the determination of the two analytes in soil sample extracts and the recoveries of pyrene (at levels of 236ng∙g-1 and 170ng∙g-1) and anthracene (334 ng∙g-1 and 510ng∙g-1) agreed well with the results from GC-MS analyses. The good recovery rates (101.8% and 102.5% for pyrene and 106.4% and 101.7% for anthracene) confirmed the reliability of the method. Graphical abstract Schematic illustration of SERS signal enhancement of pyrene, as an example of polycyclic aromatic hydrocarbons, by β-cyclodextrin modified gold nanoparticles.