An improved self-assembly gold colloid film as surface-enhanced Raman substrate for detection of trace-level polycyclic aromatic hydrocarbons in aqueous solution

To detect trace-level polycyclic aromatic hydrocarbons, some investigations of an improved self-assembly method are carried out using gold colloid films for the preparation of the surface-enhanced Raman scattering (SERS)-active substrate. Extinction spectra and scanning electron microscopy images reveal that controllable surface plasmonic metal substrates can be obtained by increasing the temperature of (3-aminopropyl)trimethoxysilane solution up to 64.5?degrees C. The SERS-active substrates have a high enhancement factor, and they can be both easily prepared and reproducible. With the use of these substrates, different concentrations of pyrene and anthracene in aqueous solutions were detected by SERS. A further enhancement can be supported by shifted excitation Raman difference spectroscopy. Raman signals of pyrene and anthracene adsorbed on gold colloid substrates up to limits of detection at 5 and 1?nmol/l, respectively, can be obtained. The quantitative analysis shows the possibility of in situ detection of polycyclic aromatic hydrocarbons while such gold colloid film serves as a SERS-active substrate. Copyright (c) 2012 John Wiley & Sons, Ltd.