Quaternized chitosan/silver nanoparticles composite as a SERS substrate for detecting tricyclazole and Sudan I

• Published in: Applied surface science 2015-10, Vol.351, p.466-473
• Main Authors: Chen, Kaihang, Shen, Zuguang, Luo, Jiwen, Wang, Xiaoying, Sun, Runcang
• Format: Article
• Language: English
• Subjects: Agglomeration; Amplification; Chitosan; Contaminants; Foods; Irradiation; Nanoparticles; Quaternized chitosan; SERS; Silver; Silver nanoparticles; Sudan I; Tricyclazole
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.05.149

•Synthesis optimization of Ag NPs with quaternized chitosan (QCS) was studied.•The size of Ag NPs was tuned by changing the DS and Mw of QCS.•QCS/Ag NPs exhibited much better SERS performance than Ag NPs without free QCS.•QCS/Ag NPs as SERS substrate detected tricyclazole in low concentration of 50ppb.•QCS/Ag NPs as SERS substrate detected Sudan I with the detection limit of 10ppm. There is an urgent need to develop a highly sensitive detection system for detecting trace amounts of food contaminants. In this study, optimal synthesis of silver nanoparticles (Ag NPs) with stable and narrow size distribution in the range of 15–25nm was performed under microwave irradiation, using quaternized chitosan (QCS) as reducing and stabilizing agent. The results showed that the ratio of QCS to [Ag(NH3)2]+, reaction temperature, irradiation time, the degree of substitution (DS) and molecular weight (Mw) of QCS had obvious effects on the formation, particle size and size distribution of Ag NPs. In addition, utilizing QCS/Ag NPs composite as SERS substrate, tricyclazole and Sudan I could be rapidly and sensitively detected with the limit of detection (LOD) as low as 50ppb and 10ppm, respectively. Compared with previously reported works, our detection system are of great stability and operability. The QCS was coated on the surface of Ag core, avoiding aggregation of Ag NPs and creating hot spots, in turn, providing superior amplification of SERS. Thus, it is believed that the QCS/Ag NPs composite could be considered as an ideal SERS-active substrate for detection of food contaminants.