Analytical and Bioanalytical Chemistry

, Volume 403, Issue 7, pp 2009–2017

Detection of melamine in milk by surface-enhanced Raman spectroscopy coupled with magnetic and Raman-labeled nanoparticles

  • Nazife Nur Yazgan
  • İsmail Hakkı Boyacı
  • Ali Topcu
  • Uğur Tamer
Original Paper

Abstract

A new method based on surface-enhanced Raman spectroscopy (SERS) has been developed for sensitive and rapid detection of melamine. Spherical magnetic-core gold-shell nanoparticles (AuNPs) and rod-shaped gold nanoparticles (nanorods) labeled with a Raman-active compound were used to form a complex with the melamine molecules. 5,5′-Dithiobis(2-nitrobenzoic acid) was used as Raman-active compound because it is readily adsorbed by a gold nanoparticle surface forming a self-assembled monolayer (SAM) and has strong Raman scattering at 1330 cm−1, because of the symmetric NO2 stretch. The calibration curve was obtained by plotting Raman band area at 1330 cm−1 against melamine concentration. A linear relationship was obtained with a high determination coefficient (R2 = 0.997). The method was validated for linearity, sensitivity, precision (intra-day and inter-day repeatability), and recovery. In the model system, the limits of detection (LOD) and quantification (LOQ) were 0.38 and 1.27 mg L−1, respectively. For melamine-spiked milk samples, LOD and LOQ values were 0.39 mg L−1 and 1.30 mg L−1, respectively. Intra and inter-day precision were 3.73 and 4.94 %, respectively. This method was applied to samples of skimmed milk that had been spiked with melamine at different concentrations. The recovery of the method was 95–109 % in the concentration range 2–15 mg L−1, and average RSD was 1.71 %. Total analysis time was less than 15 min.

Figure 1

Melamine acts as a cross linker molecule between the magnetic AuNPs and Raman-labeled nanorods

Keywords

Melamine Surface-enhanced Raman spectroscopy Magnetic nanoparticles Milk 

Supplementary material

216_2012_5971_MOESM1_ESM.pdf (132 kb)
ESM 1(PDF 132 kb)

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Nazife Nur Yazgan
    • 1
  • İsmail Hakkı Boyacı
    • 1
  • Ali Topcu
    • 1
  • Uğur Tamer
    • 2
    • 3
  1. 1.Department of Food Engineering, Faculty of EngineeringHacettepe UniversityAnkaraTurkey
  2. 2.Department of Analytical Chemistry, Faculty of PharmacyGazi UniversityAnkaraTurkey
  3. 3.Nanomedicine and Advanced Technologies Research CenterAnkaraTurkey

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