Jingyue Xu,Ying Li,Jiajia Guo,Fei Shen,Yeli Luo,Chunyan Sun
A new fluorescence method for detecting clenbuterol based on gold nanoparticles (AuNPs) and rhodamine B (RB) has been developed. It has been observed that the quenching of fluorescence of RB occurs in the present of AuNPs through the fluorescence resonance energy transfer (FRET). In the presence of clenbuterol , the FRET-based fluorescence of RB and AuNPs would be gradually recovered for the reason that clenbuterol could congregate the AuNPs and inhibit the FRET process . An assay for the determination of clenbuterol has been proposed based on the modulation in FRET efficiency between RB and AuNPs. Under the optimum conditions, the fluorescence recovery efficiency of the assay is proportional to the concentration of clenbuterol. The detection limit in swine feed was calculated to be 0.008 mg/g and the recoveries were in the range of 97%–102%. In short, the proposed method provides advantages such as rapidity, simplicity, low cost and high sensitivity, making it promising for the rapid screening of clenbuterol residues.
A simple and convenient on-line molecular imprinted solid-phase extraction flow-injection fluorescence sensor was developed in this study. Florfenicol (FF)-imprinted polymer was prepared by self-assembly with acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The binding characteristics of the imprinted polymer to florfenicol were evaluated by equilibrium binding experiments, and the morphology of the imprinted polymer was studied by scanning electron microscope (SEM). Fluorescence intensity of 3-p-nitrylphenyl-5-(2′-sulfonophenylazo) rhodanine (4NRASP) and bovine serum albumin (BSA) was inhibited by FF. Under optimum conditions the intensity of fluorescence shows a linear relationship with the concentration of FF over the range of 1.2 × 10 −6 to 2.6 × 10 −5 g mL −1 with a regression equation of Δ I = 23.54 + 17.86 c ( c 10 −6 g mL −1 ) ( r = 0.9965, n = 6). The low detection limit of FF was found to be 3.4 × 10 −7 g mL −1 according to 11 parallel determinations for the blank solution. The relative standard deviation for the determination of 2.0 × 10 −6 g mL −1 FF solution was 3.5% ( n = 11). This proposed sensor could be satisfactorily applied to the determination of FF in liver and meat samples.
Heterostructured chemosensors have excellent chemical stability, low contamination and excellent recyclability, and are regarded as a promising new generation of sensors with critical properties related to their sensing sensitivity and selectivity. Our preparation strategy for a heterostructured sensor is to construct it using a luminescent lanthanide complex and metal organic framework (MOF). A heterogeneous sensor is systematically produced using EuTTA and ZIF-8 to cover silica, and thin particles are obtained with small size and uniform morphology. Then, the particles were used as a highly selective and sensitive sensor to detect Cu2+ in aqueous solution. Eventually, we find that the well-structured silica@EuTTA@ZIF-8 microspheres have a good fluorescence stability, low detection limit and broad linear range in aqueous environments. These excellent properties make it a potential chemosensor for sensing of Cu2+ in environmental or biological solution systems.
Shanliang Song,Chuanxi Wang,Yue Zhao,Tantan Hu,Xinxin Zhou,Tianxin Zhao,Minghui Yang,Quan Lin
A dual-emission ratiometric fluorescent sensing film for metal ion detection is designed. This dual-emission film is successfully prepared from chitosan, graphitic carbon nitride (g-C 3 N 4 ), and gold nanoclusters (Au NCs). Here, it is shown that the g-C 3 N 4 not only serves as the fluorescence emission source, but also enhances the mechanical and thermal stability of the film. Meanwhile, the Au NCs are adsorbed on the surface of chitosan film by the electrostatic interaction. The as-prepared dual-emission film can selectively detect Cu 2+ , leading to the quench of red fluorescence of Au NCs, whereas the blue fluorescence from g-C 3 N 4 persists. The ratio of the two fluorescence intensities depends on the Cu 2+ concentration and the fluorescence color changes from orange red to yellow, cyan, and finally to blue with increasing Cu 2+ concentration. Thus, the as-prepared dual-emission film can be worked as ratiometric sensing paper for Cu 2+ detection. Furthermore, the film shows high sensitivity and selectivity, with low limit of detection (LOD) (10 ppb). It is observed that this novel gold-cluster-based dual-emission ratiometric fluorescent sensing paper is an easy and convenient way for detecting metal ions. It is believed that this research work have created another avenue for the detection of metal ions in the environment.
危险品化学品经营许可证（带存储）