- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A fluorescent probe for sequential sensing of MnO <sub/>4</sub><sup>?</sup> and Cr <sub/>2</sub> O <sub/>7</sub><sup>2?</sup> ions in aqueous medium based on a UCNS/TMB nanosystem
摘要： This paper reports the successful design of an UC fluorescence nanosystem for distinguishable and sequential detection of MnO4? and Cr2O72? based on the inner filter effect (IFE) between Gd2O3:Yb,Er upconversion nanospheres (UCNS) and 3,3’,5,5’-tetramethylbenzidine (TMB). The detection of MnO4? was realized by a stoichiometric oxidation reaction between TMB and Mn(VII), which resulted in quenching of the upconversion luminescence (UCL) by the blue product through IFE. The assay of Cr2O72?, in contrast, was based on the formation of complexes and the consumption of the oxidation product of the previous reaction. The sensing of MnO4? and Cr2O72? do not interfere with each other when Pb2+ was added as a masking agent. This provides a new strategy for sensitive and selective detection of MnO4? and Cr2O72?. The detection of MnO4? showed not only a low LOD of 0.243 μM but also high selectivity over other possible interfering ions. The sensitivity assay of MnO4? can be performed in the linear range of 1.85 to 69 μM. An excellent linear relationship was also found in the sensing of Cr2O72?, with a linear range of 18.3 to 250 μM and a LOD of 2.95 μM. The selectivity towards Cr2O72? was also proved to be good. Based on these properties, the UCNS–TMB nanoplatform is a potential chemosensor for both MnO4? and Cr2O72? ions in practical assays for waste water.
关键词： upconversion nanospheres,aqueous medium,UCNS/TMB nanosystem,Cr2O72?,MnO4?,TMB,fluorescent probe,inner filter effect,sequential sensing
更新于2025-11-14 17:03:37
-
Narrow resonance and ultrahigh sensitivity plasmonic waveguide refractive index sensor
摘要： A surface plasmon resonance optical refractive index sensor (for aqueous medium) with high angular and spectral sensitivities, S, very small full width at half maxima, w, (narrow resonance) and very high quality factor, χ=S/w, is proposed, which operates in both angular and spectral interrogation modes. The structure consists of a prism and a composite plasmonic waveguide consisting of a high index dielectic layer and a thin metal(Ag) film, separated by a low index layer. Above the metal film, the medium is analyte. It is shown that even with a prism of low index, the proposed sensor offers very small full width at half maxima (FWHM) of reflection spectra which improves the sensor performance. Numerically, an angular sensitivity of 168 degree/RIU and a quality factor, χ= 1680 could be achieved for the proposed configuration. Spectral sensitivity comes out to be 6000 nm/RIU.
关键词： Refractive index sensor,Aqueous medium,Surface Plasmon Resonance (SPR),Bio/Chemical sensor
更新于2025-09-23 15:19:57
-
Selective and Sensitive Fluorescence recognition of Pb(II) in aqueous medium by organic nanoparticles of a urea linker based tetrapodal receptor: Effect of linker molecules in a sensor on chemosensing
摘要： Tetrapodal framework based two compounds P and R were synthesized bearing two urea and thiourea moieties respectively. The organic nanoparticles (ONPs) were produced from P and R by re-precipitation method and their recognition behavior was studied by investigating the fluorescence emission pattern of ONPs-analyte complexes. The chemosensing studies of P-ONPs and R-ONPs revealed that P-ONPs (0.009 mM, size 20-30 nm) showed selective recognition behavior towards Pb(II) in aqueous medium among other alkali, alkaline earth and transition metal ions with the limit of detection as 1.56 μM via photoinduced electron transfer (PET)-OFF mechanism. In comparison to other metal ions, prominent peaks with higher intensity at 363 nm and 428 nm for Pb(II) were observed. R-ONPs have not shown any kind of selective chemosensing behavior. The judicially placed two urea bridges in P-ONPs are well suited for Pb(II) sensing.
关键词： urea,lead,aqueous medium,Fluorescence,chemosensor
更新于2025-09-04 15:30:14