Title: Application of gold and silver colloidal nanoparticles for the surface-enhanced Raman spectrometric analysis of melamine and 4-aminobiphenyl

Authors: Ngee Sing Chong; Katrina A. Smith; Sunil Setti; Beng Guat Ooi

Addresses: Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee, TN 37132, USA. ' Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee, TN 37132, USA. ' Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee, TN 37132, USA. ' Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee, TN 37132, USA

Abstract: Colloidal nanoparticles of gold and silver were used in Surface-Enhanced Raman Scattering (SERS) analysis of melamine and 4-aminobiphenyl. Gold colloids allowed the SERS detection of melamine at levels below 0.1 μg/L using a previously unreported SERS peak at 275 cm⁻¹ and yielded better detection limits compared to silver colloids. For 4-aminobiphenyl, the detection limits were found to be similar for both colloids at 0.05-0.1 mg/L. Analysis by transmission electron microscopy showed that the morphology of both Ag and Au nanoparticles were uniformly spherical with average diameters that were 69.3 ± 23.1 nm and 41.6 ± 19.1 nm, respectively. The SERS spectral intensities of both compounds were found to increase as the sample pH increased. The optimal signals were obtained at pH = 8.5 for 4-aminobiphenyl and pH = 11.5 for melamine. The enhancement factors for the determination of melamine are in range of 3.5 × 10⁴-6.3 × 10⁴ for the silver colloid and 5.2 × 10⁷-2.1 × 10⁹ for the gold colloid.

Keywords: surface-enhanced Raman scattering; SERS; gold colloids; colloidal nanoparticles; silver colloids; 4-aminobiphenyl; melamine; cyanuric acid; nanotechnology.

DOI: 10.1504/IJETM.2013.050681

International Journal of Environmental Technology and Management, 2013 Vol.16 No.1/2, pp.3 - 20

Received: 02 Jun 2011
Accepted: 15 Sep 2011
Published online: 17 Sep 2014 *

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