Yuxing Lian,Mengqin Zheng,Suhua Li,Wenqiang Lai,Dianping Tang,Youxiu Lin
A colorimetric and photothermal dual-mode detection method based on β-NiOOH nanozyme-3,3',5,5'-tetramethylbenzidine (TMB) system was established for Chloramphenicol (CAP) content in fruit juice. Here, a novel nanozyme β-NiOOH with high oxidase-like activity can directly and effectively catalyze the oxidation of colorless TMB to blue color TMB oxidation (oxTMB) without the presence of H2O2. Using a competition-type immunoassay, the oxTMB can induce not only a increase in absorption peak intensity but also a photothermal effect under 808 nm laser irradiation, achieving dual-mode detection of CAP. The increase of absorbance at 652 nm and the increase of temperature generated by photothermal conversion are linearly correlated with the CAP content. Under the optimal conditions, the dual-mode detection shows a low limit to 0.0056 ng/mL for the colorimetric method, and 0.0016 ng/mL for photothermal method. Moreover, the developed colorimetric and photothermal dual-mode immunobiosensor is successfully used to detect CAP in fruit juice with an acceptable recovery rate between 93.387% and 118.514%. This method has good repeatability, specificity, and accuracy, and provides an efficient approach for real-time detection of CAP in food safety analysis and detection platform.
Liming Dai,Chenchen Fang,Fanglei Yao,Xiaoyuan Zhang,Xuefeng Xu,Shangling Han,Jingyao Deng,Junwu Zhu,Jingwen Sun
In-situ generated hydroxides and oxyhydroxides have been gradually recognized as the real active sites of metal organic frameworks (MOFs) towards the oxygen evolution reaction (OER). Nevertheless, the fine phase evolution process is still less of concern and elusive. Herein, we successfully construct serious of Ni-MOFs with differing thickness ranging from 1 nm to 270 nm through a competitive coordination strategy. Utilizing the operando resonance spectroscopy, an accurate phase inversion behavior of the Ni-MOFs has been witnessed during the OER, and demonstrated as a thickness-dependent process. Ultrathin architecture is identified as a positive factor to promote the exchange between MOFs ligands and applied electrolyte during the electrochemical test. Hence, after removing most of the internal ligands, 2D MOFs favor to be transformed as β-NiOOH, which is more active than the generated γ-NiOOH in bulky system. The density function theory (DFT) calculation alongside with the in-situ electrochemistry tests further affirm the β/γ-NiOOH transformation behavior. This work offers a new understanding of the electrocatalytic mechanism from the view point of phase evolution in 2D MOFs.
In this paper, oleophilic and superhydrophobic sponges were successfully constructed via a one-pot low temperature hydrothermal method anchoring three-dimensional rambutan-like-β-NiOOH microspheres into sponge skeletons and lauric acid modification. The constructed modified three-dimensional rambutan-like-β-NiOOH @sponge (the static contact angle of 153.5°) possessed outstanding oil sorption capacity (separation efficiency is nearly 99%) towards the various organics/oils and excellent recyclability after 30 cycles of adsorption-squeezing. Importantly, modified three-dimensional rambutan-like-β-NiOOH @sponge is capable of separating surfactant-stabilized water-in-oil emulsions and can be utilized for continuous oil-water separation with the aid of a peristaltic pump. This is mainly due to the fact that the three-dimensional hierarchical rambutan-like micronano structure formed by self-assembly with high specific surface area provides a large number of hydrophobic interfaces to improve the hydrophobic properties of sponges. This work presents a new strategy for the designs multitasking oil-water separation materials.
危险品化学品经营许可证（带存储）