Prepared Three-Dimensional Flower-Like MoS ₂/Ag@rGO Nanocomposite as Self-Cleaning SERS Substrate for Trace Detection 17β-Estradiol in Environmental Water

Abstract

17β-E2 was the most active sterol estrogens and was widely used in animal husbandry for animal fattening and increasing milk production. Its abuse has resulted in residues in the environment. The concentration of 17β-E2 had been detected in agricultural groundwater where livestock fertilizers were used in the range of 6-66 ng/L. However, even very low concentrations could still enter the human body through the enrichment of the food chain and have adverse effects on the endocrine system. In order to satisfy the trace detection of 17β-E2 the SERS analysis method with high sensitivity, simple operation and fingerprint recognition effect was proposed for the detection of 17β-E2 in environmental water.In order to achieve high sensitivity detection of SERS, cheap Ag NPs was selected as SERS source. MoS2 not only provided a platform for the regular arrangement of Ag NPs, but also gave the material self-cleaning functions due to its ability to photogenically the degradation of organic matter. Finally, MoS2/Ag was wrapped with rGO. On the one hand, rGO could protect Ag NPs and avoid its oxidation during storage and use. On the other hand, it could adsorb target molecules and pull the distance between target molecules and Ag NPs, thus enhancing SERS signal. The material had high SERS enhancement factor (EF=1.95 × 107), low detection limit (LOD=5 × 10-12 M), good linear relationship (R2=0.994) in the concentration range of 10-11 -10-6 M, good stability (daytime relative standard deviation RSD=4.74%), and strong anti-interference ability. The recovery of 17β-E2 in farm wastewater samples were 100.15% - 108.00%, and RSDs were 1.09%-2.57%.

Keywords: 17β-estradiol, Surface Enhanced Raman Spectroscopy, MoS2/Ag@rGO, Self-cleaning