Xu Yi,Kutsanedzie Felix Y. H.,Ali Shujat,Wang Pingyue,Li Chunyan,Ouyang Qin,Li Huanhuan,Chen Quansheng
Lead ion (Pb 2+ ) accumulation in food consumed by humans and animals possess health threats and effects. The development of a senor for its monitoring at its minutest accumulation in edible materials becomes an antidote to safeguarding human lives. A fabricated fluorescence-based sensor made of carboxyl modified upconversion nanoparticles (UCNPs), gold nanorods (GNRs), and cysteamine (Cys) were used as energy donor, receptor and a bridge respectively for the rapid sensing of Pb 2+ in Matcha. The UCNPs-Cys-GNRs sensor showed weak fluorescence signals due to the FRET, and was inhibited in the presence of Pb 2+ to form a complex with Cys, and the consequent recovery of fluorescence signals. Under optimized conditions, a good linear relationship was established between the relative fluorescence intensity and Pb 2+ concentrations from 1 to 100 μM with a low detection limit (LOD) of 0.5 μM. The developed sensor was applied to detect Pb 2+ in Matcha samples with recoveries within 93.99—102.16% and relative standard deviations (RSD) < 8%. Satisfactory results (p > 0.05) were obtained upon validation using a standard inductively coupled plasma mass spectrometry (ICP-MS).
Yan Li,Yang Si,Xueqin Wang,Bin Ding,Gang Sun,Gang Zheng,Wenjing Luo,Jianyong Yu
A facile, ultrasensitive, reproductive and selective sensor strip utilizing electrospun polyamide-6/nitrocellulose (PA-6/NC) nano-fibers/nets (NFN) membranes assemble bovine serum albumin decorated Au nanoparticles (BAu probe) for naked-eye colorimetric assay of Pb 2+ has successfully prepared through dual-component alternate distribution multifluidic electrospinning technique . Benefiting from the extremely large specific surface areas and high porosity of NFN membranes, the stability of BAu probe dramatically increased and the strips presented a significant absorbance decreasing band at 546 nm which induce the visual color changes from deep pink to white after incubated in Pb 2+ liquor with a low detection limit of 0.2 μM without any assistance of equipment. Upon exposure to a series of metal ions , only Pb 2+ could induce a pink-to-white color change, which clearly exhibited that BAu probe immobilized PA-6/NC membranes could act as highly selective strips to detect Pb 2+ with little interference from other metal ions. Additionally, the colorimetric responses are represented in visualized quantitative by calculated color difference from L ⁎ a ⁎ b ⁎ coordinates which are presented with lightness and chrome values. Furthermore, the sensitivity of NFN membrane-based strips is much higher than that of film-based ones. The results indicate that this promising cost-effective sensing system could potentially allow for assaying of Pb 2+ in human urine or blood as preliminary screening of lead poisoning.
In this study, an ordered spatial chelating resin was synthesized, and its selective adsorption of various cations was investigated. By using polyethyleneimine (PEI) as the main chain, methoxy biphenyl group as the rigid group, and methylene units as the flexible chains, a series of side-chain liquid crystal chelating resins were synthesized (labeled as POMen, where n is the spacer length varying between three to six methylene units). The analysis of the thermal properties of POMens showed that they are thermotropic liquid crystals with smectic structure. In its liquid state, out of all POMens, POMe6 demonstrated excellent adsorption capacity relative to Pb 2+ with maximum value equal to 387 mg/g. In particular, L-POMe6 demonstrates an excellent selectivity for the removal of Pb 2+ in the presence of competitive heavy metal ions. Density functional theory (DFT) calculations were carried out to analyze the binding energies of L-POMe6 structures and their corresponding metal ion complexes. L-POMe6 demonstrated the lowest binding energy with Pb 2+ complexes compared other complexes. Furthermore, the adsorption of Pb 2+ onto L-POMe6 adsorbents fitted to the Langmuir adsorption and pseudo-second-order kinetic model. The regeneration capacities of L-POMe6 were studied, that the adsorption capability remains high after several cycles of adsorption-desorption process.
危险品化学品经营许可证（带存储）