title: Selective determination of melamine in milk samples using 3-mercapto-1-propanesulfonate-modified gold nanoparticles as colorimetric probe.
abstract: A novel and sensitive colorimetric method for determination of melamine in milk samples was developed by a 3-mercapto-1-propanesulfonate-modified gold nanoparticles (MPS-GNPs) probe. Melamine molecule has multiple -NH(2) groups. These functional groups can interact with MPS to form strong hydrogen bonding and induce the aggregation of the MPS-GNPs, resulting in a dramatic color change from red to blue. Therefore, the concentration of melamine in milk samples can be quantitatively detected by the naked eyes or a UV-vis spectrometer. Moreover, investigations have revealed that the sensitivity of the detection could be clearly improved by adding NaCl to the modified GNPs solution, which leads to a more rapid color change in the NaCl-optimized GNPs system. It is worth noting that the absorption ratio (A(650)/A(520)) of the modified GNPs in the NaCl-optimized system exhibited a linear correlation with melamine concentration and the limit of detection is 8 nM, well below the safety limit (1 ppm for infant formula in China).
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Taian, Shandong, PR China.
authors.forename: Haichao
authors.initials: H
authors.lastname: Su
authors.forename: Hai
authors.initials: H
authors.lastname: Fan
authors.forename: Shiyun
authors.initials: S
authors.lastname: Ai
authors.forename: Na
authors.initials: N
authors.lastname: Wu
authors.forename: Hongmin
authors.initials: H
authors.lastname: Fan
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Bian
authors.forename: Jianchao
authors.initials: J
authors.lastname: Liu
mesh_terms: D017738:Alkanesulfonic Acids / Q000737:chemistry*; D000818:Animals; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008892:Milk / Q000737:chemistry*; D008956:Models, Chemical; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000737:chemistry; D013053:Spectrophotometry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014227:Triazines / Q000032:analysis*
chemical_list: D017738:Alkanesulfonic Acids; D013438:Sulfhydryl Compounds; D014227:Triazines; C068559:propylsulfonic acid; D012965:Sodium Chloride; D006046:Gold; C011907:melamine