| In recent years, with the development of the nuclear industry, a large-scale uranium mining cause surface water, groundwater, soil, atmosphere and ecosystem radioactive pollution, environmental geological hazards, soil erosion and many other issues. It is said that uranium and its compounds are threatens to human health and safety for its high carcinogenicity and biotoxicity. Therefore, it is of great significance to establish a simple,fast, sensitive method to detect them. Gold nanoparticles with special optical properties,strong Surface Plasmon Resonance and easy surface functionalization make its broad space to be used in bioanalytical assay, detection of heavy metal ions. In this research paper,three colorimetric sensors including imid-Au NPs,IMID-Au@Si O2 and Au@Si O2-DPTS have been prepared for colorimetric detection of U(VI).(1) Au@Si O2 cofunctionalized with diethylphosphatoethyltriethoxysilane(DPTS) is used as selective colorimetric sensors for uranyl ion detection. The aggregation in the presence of UO22+ is due to binding with chelating ligands( –PO43-), yielding a red-to-bule color change, and could be monitored by naked eyes as well. By optimized the condition of p H, the concentration of TEOS, the substrate concentration and reaction time,Au@Si O2-DPTS shows high selectivity to UO22+in comparison with other 17 metal ions(Ni2+, Co2+, Mn2+ etc.,). Under optimum conditions, the absorbance ratio(A600/A523)was linear with the UO22+concentration in the range of 4.23-10.28 μmol/L(Y=0.0118X+0.0967(R2=0.99)), the detection limit of UO22+ could be as low as 4.85×10-7mol/L.With the help of synergism action of L-Cystine and diethylphosphatoethyltriethoxysilane,detecting effect of the colorimetric sensor is optimized. The range of p H gets wider,reaction time shortened to 5 min, its detection limit is as low as 7.1×10-8 mol/L.(2) N-(3-Aminopropyl)-imidazole functionalized gold nanoparticles is used as a colorimetric sensor for uranyl ion detection. The metal chelation of imidazole groups and uranyl ions induces the aggregation of nanoparticles, which leads to the remarkable changein color from wine red to blue. It can be easily observed by naked eyes, which is particularly applicable to on-site and real-time detection. By optimized the condition of p H,the substrate concentration and contact time, imid-Au NPs shows high selectivity to UO22+in comparison with other 11 metal ions(Ni2+, Co2+, Mn2+etc.,). Under optimum conditions,the absorbance ratio(A678/A540) was linear with the UO22+ concentration in the range of1.5-13.36 μmol/L(Y=0.1552X+0.4526(R2=0.90)), the detection limit of UO22+ could be as low as 5.84×10-8 mol/L.(3) Au@Si O2 cofunctionalized with N-[3-(Triethoxysilyl)propyl]-4,5-dihydroimidazole(IMID) used as selective colorimetric sensors for uranyl ion detection. The aggregation in the presence of UO22+is due to binding with imidazole groups, yielding a wine red-to-bule color change, and could be monitored by naked eyes as well. By optimized the condition of p H, the concentration of TEOS, the substrate concentration and reaction time,IMID-Au@Si O2 shows high selectivity to UO22+ in comparison with other 12 metal ions(Ni2+, Co2+, Mn2+etc.,). Under optimum conditions, the absorbance ratio(A621/A532)was linear with the UO22+ concentration in the range of 0.42-4.23 μmol/L(R2=0.99), the detection limit of UO22+could be as low as 1.1×10-7 mol/L.Keywords: gold nanoparticles; Au@Si O; core-shell structure; colorimetric detection;... |
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