Determination of dysprosium by resonance light scattering technique in the presence of BPMPHD

pH-Responsive Biocompatible Fluorescent Hydrogel for Selective Sensing and Adsorptive Recovery of Dysprosium

The elevated accumulation of electronic wastes, especially containing Dysprosium ion [i.e., Dy(III)], is emerging as a potential environmental threat. To overcome the deleterious effects of Dy(III), detection and removal of Dy(III) is crucial. Moreover, recovery of high-value Dy(III) is economically beneficial. However, the availability of a single material, capable of sensing Dy(III) in nanomolar concentration and simultaneously adsorbing it with high adsorption capacity (AC), is rare. Therefore, to solve this problem, a pH-responsive fluorescent amino graphene oxide-impregnated-engineered polymer hydrogel (AGO-EPH) has been synthesized, suitable for selective sensing of Dy(III) in nanomolar concentration and adsorbing it from wastewater at ambient temperature. This terpolymeric hydrogel is synthesized from two nonfluorescent monomers, propenoic acid (PNA) and prop-2-enamide (PEAM), along with an in situ generated comonomer (3-acrylamidopropanoic acid/AAPPA) through N-H activation during polymerization. Surface properties and structural details of AGO-EPH are established using NMR, FTIR, XRD, TEM, SEM, EDX, Raman, MALDI-mass, and DLS studies. The AGO-EPH exhibits blue fluorescence with selective turn-off sensing of Dy(III) with the detection limit of 1.88 × 10-7 (M). The maximum AC of AGO-EPH is 41.97 ± 0.39 mg g-1. The developed AGO-EPH shows consistent adsorption-desorption property over five cycles, with more than 90% desorption efficiency per cycle, confirming significant recovery of the valuable Dy(III). From Logic gate calculations, complexation of Dy(III) and AGO-EPH may be the reason behind fluorescence quenching. The AGO-EPH also shows antibacterial action against ∼3 × 108 cells mL-1 of E. coli solution. Overall, the developed pH-responsive engineered hydrogel can be used as a potential low-cost sensing device and reusable adsorbent for Dy(III).

Praseodymium selective fluorescence recognition based on GdPO4: Tb3+ probe via energy transfer from Tb3+ to Pr3+ ions

A novel strategy is proposed based on the efficient energy transfer from Tb³⁺ to Pr³⁺ for the sensitive and selective discrimination of praseodymium ions due to the matched energy levels of ⁵D₄ (Tb³⁺) and ³P₀ (Pr³⁺). The electron of Tb³⁺ transfers from the ground state to the excited state under the excitation of ultraviolet light and relaxes to the ⁵D₄ level. In the presence of Pr³⁺ the electron has no time to return to the ground state, thus it transfers to the ³P₀ level of Pr³⁺ resulting in the quenching of Tb³⁺ luminescence. In the case of GdPO₄: Tb³⁺ nanowire, its fluorescence intensity at 545 nm linearly decreased when Pr³⁺ concentration ranged from 1 × 10^-7 to 1 × 10^-5 M, and the detection limit was 75 nM. To further investigate the sensing mechanism, CePO₄: Tb³⁺, YPO₄: Tb³⁺, and YBO₃: Tb³⁺ nanoparticles were also synthesized for Pr³⁺ ion detection. For all materials, similar fluorescence quenching by Pr³⁺ ions occurred, which confirmed the efficient energy transfer from Tb³⁺ to Pr³⁺ ions. Utilizing the matched energy levels of ⁵D₄ (Tb³⁺) and ³P₀ (Pr³⁺), for the first time, we proposed a novel strategy (taking GdPO₄: Tb³⁺ probe as the example) based on the efficient energy transfer from Tb³⁺ to Pr³⁺ for the sensitive and selective discrimination of praseodymium ions.

Surface Sensitive Techniques for Advanced Characterization of Luminescent Materials

The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants. The role of XPS to determine the presence of defects in the phosphor matrix is also stated with the different examples. The role of HRTEM in combination with Energy dispersive spectroscopy (EDS) for nanoparticle characterization is also pointed out.

Determination of protein by resonance light scattering technique using dithiothreitol-sodium dodecylbenzene sulphonate as probe

The resonance light scattering (RLS) spectra of bovine serum albumin (BSA)-dithiothreitol (DTT)-sodium dodecylbenzene sulphonate (SDBS) and its analytical application were investigated. The RLS intensity of this system can be effectively enhanced in the presence of BSA. Based on the enhanced RLS intensity, a simple assay for BSA was developed. The experimental results indicate that the enhanced RLS intensity is proportional to the concentration of BSA in the range from 1.0 x 10(-8) to 7.5 x 10(-7) mol L(-1) with the determination limit of 5.0 x 10(-9) mol L(-1). The effects of pH, concentration of SDBS and DTT on the RLS enhancement were discussed. Most metal ions have little interference on the determination of BSA. Some synthetic and real samples were analyzed, and the results obtained were in good agreement with those obtained by Bradford method.

A sensitive rutin assay using a simple probe manganese sulfate based on its novel resonance light scattering decrease phenomenon

A novel resonance light scattering (RLS) decrease method was developed to determine rutin with a simple probe manganese sulfate. At pH 7.5, the strong RLS intensity of manganese sulfate was remarkably decreased by the addition of rutin with the maximum peak located at 389.0 nm. Under the optimum conditions, a good linear relationship between the changes of RLS intensities of manganese sulfate with and without rutin and the concentrations of rutin was obtained over the range of 0.49-24.4 microg ml(-1) and a low detection limit (3sigma) 0.42 microg ml(-1) was achieved in the mean time. Based on this approach, a novel method for quantitative analysis of rutin is proposed in this paper. The method proposed was also applied successfully to the determination of rutin in commercial pharmaceutical preparations of compound rutin tablets and human urine samples. The assay is sensitive, rapid, inexpensive, practical and relatively free from interference generated by coexisting substances.

Micro-determination of nucleic acids with a simple probe manganese chloride based on the fine enhanced resonance light scattering

Manganese chloride can form large particles with nucleic acids by electrostatic forces, which results in strong enhancement of resonance light scattering (RLS) signals. Based on this phenomenon, a novel and very simple assay of DNA was established. The work conditions have been investigated including the concentration of probe, the acidity of solution, the effect of ionic strength and the selectivity. In acidic solution, the enhanced RLS intensity at 389.5 nm was proportional to the concentration of nucleic acids in the range 0.05-10.0 microg ml(-1) for both ctDNA and fsDNA and 1.0-10.0 microg ml(-1) for yRNA. The limits of detection (LOD, 3sigma) were 0.17, 0.13 and 0.53 ng ml(-1) for ctDNA, fsDNA and yRNA, respectively. Synthetic samples were determined satisfactorily.

Dysprosium(III) Ion-Selective Electrochemical Sensor Based on 6-Hydrazino-1,5-diphenyl-6,7-dihydropyrazolo[3,4-d]pyrimidine-4(5H)-imine

A Dy(III) ion-selective electrode based on 6-hydrazino-1,5-diphenyl-6,7-dihydropyrazolo[3,4-d]pyrimidine-4(5H)-imine (HDDPI) as an excellent sensing material was developed. The sensor exhibits a Nernstian behavior (a slope of 19.6 ± 0.3 mV per decade) over a wide concentration range (from 1.0 × 10-1 to 8.0 × 10-7 M Dy) with a detection limit of 4.2 × 10-7 M. The sensor response is independent of pH of the solution in the pH range 3.5-8.3. The sensor possesses the advantages of short conditioning time, fast response time (<10 s) and in particular, good selectivity and sensitivity to the dysprosium ion in the presence of a variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor also showed a great enhancement in selectivity coefficients for dysprosium ions, in comparison with the formerly mentioned dysprosium sensors. The electrode can be used for at least 10 weeks without any considerable divergence in the potentials. The proposed electrode was successfully used as an indicator electrode in potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also used in the determination of concentration of F- ions in some mouth washing solutions and in the Dy3+ recovery from solution.