In situ detection and identification of dyes from a complex chemical mixture presents a great challenge to analytical chemists. Au NPs were uniformly deposited on magnetic Fe3O4@SiO2 bead to form a core-satellite Fe3O4@SiO2-AuNPs (FSPA) hetero-nanostructure, with tunable loading density via layer by layer polyelectrolyte encapsulation method. Further layer by layer decoration of polyelectrolyte outside satellite structure induced a high sensitive toward negatively and positively charged food dye molecules. The fabricated magnetic satellite structures were used as surface-enhanced Raman scattering (SERS) substrate for the selective detection of food dyes. Our results demonstrated when the FSPA substrate wrapped with positively polyelectrolyte, it could selectively increase the SERS signal for negatively charge sunset yellow, SY(-), but not for malachite green, MG(+), and indigo (neutral charge). On the other hand, when the surface charge was tuned to negative, this FSPA substrate then only respond to MG (+) but not the other two. This magnetic SERS substrate was also successfully applied in detecting food dyes in commercial beverages. As a result, this SERS platform provides an easy and fast screening technique for in situ analysis of food dyes and molecules with charge.
Journal: TechConnect Briefs
Volume: 1, Advanced Materials: TechConnect Briefs 2015
Published: June 14, 2015
Pages: 332 - 335
Industry sector: Advanced Materials & Manufacturing
Topic: Nanoparticle Synthesis & Applications