Chondroitin sulfate, a type of glycosaminoglycan, is a linear polysaccharide which possesses high negative charges in its sulfate and carboxylate groups. Green synthesis of gold nanoparticles (AuNPs) is performed using chondroitin sulfate (CS) by mixing gold salts and CS with heating. No other chemicals are used for the synthetic steps providing a complete green route. The as-prepared AuNPs (CS-AuNPs) are characterized by microscopic and spectroscopic methods. The result from the inductively coupled plasma-atomic emission spectroscopy indicates that the reaction yield is 80.1%. Spherical shaped AuNPs that have an average diameter of 44.7 nm were observed by the atomic force microscopy. Interestingly, the CS chains positioned between the AuNPs play an important role as a stabilizer. Detecting melamine using the CS-AuNPs is a simplified nanosensing method compared to other conventional methods. When the melamine concentration of the AuNP solution increases, the intensity of the UV-visible absorbance at 530 nm decreases. Meanwhile, a new peak appeared at 620 nm, which offers a linear relationship between the absorbance ratio (A620/A530) in the range of 0.1�10 �M of melamine concentration. The melamine spiked in real infant formula is quantified with CS-AuNPs solution at concentrations as low as 12.6 ppb. For a quick on-site screening of melamine in milk products, melamine nanosensing using CS-AuNPs could be a promising technique.

Green synthesis of gold nanoparticles using chondroitin sulfate and their applications for melamine nanosensing

248th National Meeting (2014)

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