Quantitative determination of melamine in milk using Ag nanoparticle monolayer film as SERS substrate

• Published in: Physica. E, Low-dimensional systems & nanostructures Low-dimensional systems & nanostructures, 2017-04, Vol.88, p.164-168
• Main Authors: Li, Ruoping, Yang, Jingliang, Han, Junhe, Liu, Junhui, Huang, Mingju
• Format: Article
• Language: English
• Subjects: Ag NP monolayer film; Melamine; Milk; Quantitative detection; Surface-enhanced Raman Scattering (SERS)
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2016.12.013

A Raman method employing silver nanoparticle (Ag NP) monolayer film as Surface-enhanced Raman Scattering (SERS) substrate was presented to rapidly detect melamine in milk. The Ag NPs with 80nm diameter were modified by polyvinylpyrrolidone to improve their uniformity and chemical stability. The treatment procedure of liquid milk required only addition of acetic acid and centrifugation, and required time is less than 15min. The Ag NP monolayer film significantly enhanced Raman signal from melamine and allowed experimentally reproducible determination of the melamine concentration. A good linear relationship (R2=0.994) between the concentration and Raman peak intensity of melamine at 681cm−1 was obtained for melamine concentrations between 0.10mgL−1 and 5.00mgL−1. This implies that this method can detect melamine concentrations below 1.0mgL−1, the concentration currently considered unsafe. •The Ag NP monolayer film (ANMF) has ultrahigh sensitivity and reliability.•The use of polyvinylpyrrolidone increases uniformity and stability of Ag NPs.•The treatment of liquid milk only requires acetic acid and centrifugation.•ANMF substrate allows reproducible determination of melamine concentration.•The results of quantitative analysis demonstrate an excellent linearity (R2≈0.994).