Ma Fangfang,Liang Sheng,Peng Yibo,Kuang Yangfang,Zhang Xing,Chen Shu,Long Yunfei,Zeng Rongjin
Novel fluorescent silver nanoclusters (AgNCs) were synthesized using amido black 10B (AB) as a stabilizing agent and then employed for the detection of copper ions (Cu 2+ ). The AB-stabilized AgNCs (AB–AgNCs) were well dispersed in aqueous solution with an average diameter of around 1.3 nm and exhibited illustrious blue fluorescence emission. Moreover, the fluorescence of AB–AgNCs could be quenched efficiently by Cu 2+ , which might be a result of the coordination between Cu 2+ and the free recognition group of AB on surfaces of AB–AgNCs, inducing the aggregation of AB–AgNCs. Based on the linear decrease of fluorescence intensity, the Cu 2+ concentration was determined in the range of 0.01–1.1 μmol L −1 and the limit of detection (LOD) was 4.0 nΜ. In addition, the detection of Cu 2+ could be performed with AB–AgNCs in the presence of other ions, including 13 kinds of conventional metal ions and 11 kinds of anions. Based on the above experiment, the developed AB–AgNC probe was successfully further applied to detect Cu 2+ in three electroplating effluents, which showed high accuracy.
The process of synthesised silver nanoclusters and the application for Cu 2+ detection.
In this study, a gold nanoparticles colorimetric probe (AuNPs) with direct response to mercury ions (Hg 2+ ) were developed using treated N-methylpyrrolidone (NMP) and chloroauric acid (HAuCl 4 ) as precursors. NMP showed good reducibility after high temperature hydrolysis and could be used as reducing and stabilizing agent to synthesize AuNPs. The prepared AuNPs have obvious characteristic absorption peaks and appear wine-red. At the same time, it was found that the presence of Hg 2+ can cause the aggregation of AuNPs, increased the absorbance at 700 nm, and changed the color of the solution into blue-gray. This method is capable of sensitive and specific determination of Hg 2+ ranging from 1 to 30 μM, with the limit of detection (LOD) at 0.3 μM. The method showed good specificity for the determination of Hg 2+ and has the potential to be applied to Hg 2+ detection in sewage samples in the environment.
In this study, Sn@C composite was fabricated from ZnSn(OH) 6 through a green thermal calcination method. For the first time, this composite was used as a modifier on glassy carbon electrode (GCE) to construct an electrochemical biosensor to detect acetaminophen (AC). The Sn@C sensor exhibited distinctly enhanced performance in electrochemical response to AC compared with bare GCE, GCE modified with Sn and GCE modified with graphene. The linear range is 0.2–100 μM and the limit of detection (LOD) is 0.020 μM based on DPV analysis. The excellent electrochemical behavior can be ascribed to the outstanding conductivity of metal Sn and carbon, and the strong adsorption of the carbon layer to AC. Most importantly, the chemical interaction between Sn and C through Sn-C bond facilitated the electron transfer process in the electrooxidation of AC. Finally, the Sn@C sensor was successfully applied in pharmaceutical samples and spiked serum samples to detect AC with satisfactory recoveries.
Surface-enhanced Raman scattering (SERS) as a powerful sensing tool has been widely used in the food and medical sciences as it is a rapid, convenient and sensitive mean of detecting chemicals, proteins, microorganisms, etc. A variety of different SERS substrates have been fabricated by using conventional methods to contribute to the practical applications of SERS sensing. Inspired by the noble metals which have excellent SERS activity, silver (Ag) is used in this study to coat cotton fabric on a large-scale by using magnetron sputtering. The properties of Ag-coated cotton fabric samples as SERS substrates are evaluated by Raman spectra of the molecular probe, and the mechanisms are also discussed by using finite-difference time-domain simulation and 3D Raman mapping. Its limit of detection for thiram is far lower than the national standard, thus indicating that the substrate in this study is an excellent SERS substrate for use in food science.
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