Raman probing trace melamine in milk by a functionalized test paper

The rapid sensing for melamine in milk products has been developed with a portable Raman system based on the facile synthesis of tri-sodium citrate and dodecasodium of phytic acid (IP6) dual-functionalized gold nanoparticles modified filter paper, shortly named IP6-TC@Au NPs test paper. The tri-sodium citrate improved the sensitivity of Raman probe and the later kept the shelf stability. The limit of detection for melamine in water is 5 mu M (0.63 ppm) and it is 10 mu M (1.26 ppm) for testing real milk sample, which is well below the FDA's tolerance level of 2.5 ppm in milk. The proposed easy assay of IP6-TC@Au NPs test paper combining with portable Raman system could be applied for on-site monitoring melamine in milk products. (C) 2013 Elsevier B.V. All rights reserved.