Herein, we propose a simple and effective strategy for designing a ratiometric fluorescent nanosensor. We designed and developed a carbon dots (CDs) based dual-emission nanosensor for vanadium(V) by coating the surface of dye-doped silica nanoparticles with CDs. The fluorescence of dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBrO 3 ) oxidation. V(V) could catalyze KBrO 3 oxidation reaction process, resulting in the ratiometric fluorescence quenching of dual-emission silica nanoparticles. We investigated several important parameters affecting the performance of the nanosensor. Under the optimized conditions, the detection limit of this nanosensor reached 1.1 ng mL − 1 and the linear range from 10 to 800 ng mL − 1 . Furthermore, we found that the sensor was suitable for determination of V(V) in different mineral water samples with satisfactory results.
A simple, rapid, facile and ultrasensitive chemiluminescence (CL) sensor was developed for detection of Mn 2+ in mineral water samples. The developed CL sensor was based on the enhancement effect of manganese ion (Mn 2+ ) on the CL between luminol-modified AuNPs and AgNO 3 system. In the absence of Mn 2+ , the CL intensity from the luminol-modified AuNPs and AgNO 3 was relative weak owing to the bad stability of superoxide anion radical (O 2 − ) which was the key intermediate for the CL reaction. However, the addition of Mn 2+ to this CL system would generate hydrogen peroxide (H 2 O 2 ) according to the specific reaction of Mn 2+ and O 2 − . The produced H 2 O 2 had a better stability and reaction activity, thereby enhancing the CL emission. This phenomenon allowed to selective and highly sensitive detection of Mn 2+ . Under the optimal sensing conditions, the developed CL sensor showed a wide linear range for Mn 2+ detection in the range of 1–600 nM, with a detection limit of 0.3 nM at a signal-to-noise of 3. This sensitivity was about 2–3 orders of magnitude higher than that reported techniques based on metal nanoparticles-based optical sensors . In addition, the developed CL sensor exhibited excellent selectivity toward Mn 2+ over other metal ions , and it had a good stability and reproducibility.
Yun-Kai Lv,Wei Zhang,Meng-Meng Guo,Fang-Fang Zhao,Xiao-Xue Du
A home-made centrifugal microextraction tube (CMET) was developed and applied to cloud point extraction coupled with microwave-assisted back extraction and gas chromatographic separation of six phthalate esters (PAEs) from mineral water. All phthalate esters were entrapped in the micelles of the non-ionic surfactant Triton X-114 and removed from the bulk phase by centrifugation. The obtained surfactant-rich phase was treated with water-immiscible solvents, and the target analytes were back extracted by short-term microwave application and determined by GC-FID directly. The whole process was finished in the CMET. The proposed method demonstrated good performance concerning linearity (R2 = 0.9977-0.9998), precision (2.3–5.7%), the limits of detection and quantitation (LOD, 11.5-19.3 μg L−1; LOQ, 37.0-63.3 μg L−1), spiked recoveries (89.1–96.3%) and enrichment factor (71-85). The proposed method was successfully applied for the determination of trace amount of phthalate esters in mineral water. DBP and BBP were found in actual mineral water samples.
Membrane fouling is one of the difficult challenges that restrict the efficient application of membrane separation technology in oil/water separations. Hydrogel with strong hydration capability has been considered as an ideal material for preparing anti-oil-fouling coating for membranes. Although some hydrogel-based coatings have been developed for the membrane interface hydrophilization modification, controlling the morphology of gel layers and improving the flux of hydrogel coated membranes remains a difficult matter to resolve. In this study, we elegantly designed a new mineral-hydrogel coating with nanostructures to modify hydrophobic polyvinylidene fluoride (PVDF) microfiltration membranes by an alternate quaternary soaking strategy. Compared with the merely hydrogel-coated membrane, the pure water flux of novel mineral-hydrogel coating membrane increased by 214% and the permeation increased by 127% with the oil rejection rate of 99.6% at 0.4 bar. Most importantly, the newly-built mineral-hydrogel layer on porous support possessed excellent hydrophilicity, underwater super-oleophobic properties and superior anti-oil-fouling performance, which is greatly promising in oily sewage remediation. In addition, this mineral-hydrogel coating could also be constructed on other hydrophobic substrates successfully, such as commercial melamine resin. Our facile strategy for designing and constructing synergetic mineral-hydrogel architecture may also inspire other functional coatings with nanostructures.
危险品化学品经营许可证（带存储）