The quantification of albumin levels in biological samples is a critical biomarker for diagnosing and monitoring various pathological conditions. This study introduced a vitamin B 6 cofactor derived Schiff base (E)‐(4‐(((2‐(1H‐benzo[d]imidazol‐2‐yl)phenyl)imino)methyl)‐5‐hydroxy‐6‐methylpyridin‐3‐yl)methyl dihydrogen phosphate (BMLP) via the condensation of pyridoxal 5′‐phosphate with 2‐(1H‐benzo[d]imidazol‐2‐yl)aniline. Schiff base BMLP formed a complex with Fe 3+ in 2:1 binding ratio and redshifted its fluorescence emission from 417 to 474 nm, accompanied by slight quenching at 417 nm and fluorescence enhancement at 474 nm. The in situ formed BMLP─Fe 3+ complex was employed for the ratiometric fluorescence sensing of albumins, that is, human serum albumin (HSA) and bovine serum albumin (BSA). With the addition of HSA and BSA, the fluorescence emission of BMLP─Fe 3+ complex was quenched at 474 nm and enhanced at 417 nm. The selective ratiometric response from the BMLP─Fe 3+ complex can be employed to detect HSA and BSA down to 3.8 and 3.6 µM, respectively. The developed fluorescence‐based sensing approach was applied for quantifying HSA and BSA in real biological matrices, including milk and urine, with satisfactory recovery rates.
A reduced graphene oxide/manganese dioxide (rGO/MnO 2 ) was prepared via a reflux method. MnO 2 was prepared by the combustion method using neem leaf extract as a biogenic fuel. The materials were characterized using X‐ray diffraction, Brunauer–Emmett–Teller, transmission electron microscopy, high‐resolution transmission electron microscopy, selected area electron diffraction, EDS, XPS, UV–vis, and photoluminescence spectroscopy. The rGO/MnO 2 exhibited outstanding photocatalytic degradation of methyl violet (MV), achieving ~99.21% removal within 70 min under UV irradiation. The radical scavenging assays demonstrated markedly improved antioxidant activity for rGO/MnO 2 , with a half‐maximal inhibitory concentration (IC 50 ) of 186.77 μL/μg compared to rGO and MnO 2 . Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) revealed a specific capacitance of 132.71 F/g for the composite electrode, nearly double the performance of bare MnO 2 . The electrode also demonstrated superior electrochemical sensing toward Hg 2+ and Cr 2+ metal ions, with lower limits of detection (LOD: 5.94 and 12.42 μM). These results collectively establish rGO/MnO 2 as a nanocomposite with strong potential for environmental and energy storage studies.
Perfluorooctanoic acid (PFOA), a persistent organic pollutant, poses significant environmental and health risks due to its widespread occurrence in water sources and resistance to degradation. This study investigates zinc(II) terpyridine (Zn–tpy) complexes as molecular receptors for PFOA, demonstrating capture via carboxylate binding to Zn(II) with concomitant changes to nuclear magnetic resonance (NMR) and absorbance spectra. The capture capability and redox properties of the complexes were used to develop an electrochemical method for PFOA at a glassy carbon (GC) electrode modified with a thin discontinuous Nafion overlayer that assists with preconcentration at the sensor. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square‐wave voltammetry (SWV) were used to characterize the modified electrode. The electrode gave a limit of detection (LOD) of 0.407 pM and a linear range of 0.5–10 pM, with short‐term intra‐ and interelectrode relative standard deviations (RSD) of 0.94% and 2.02%. Recoveries of 96%–98% were obtained for Cork tap water spiked with PFOA after 1:100 dilution in phosphate‐buffered saline (PBS). The preliminary data suggests Zn–tpy complexes in combination with selective coatings may be applicable for class‐selective electrochemical detection of perfluoroalkyl carboxylic acids, exemplified herein using PFOA.
One of the most important processes in creating sustainable monomers for high‐performance polymers is the catalytic dehydration of sorbitol obtained from biomass to isosorbide. This study investigated a series of sulfated Zr x Sn 1 − x O 2 ( x = 0.1–0.9) mixed oxides prepared by coprecipitation method for sorbitol dehydration under solvent‐free conditions. Comprehensive evaluation of different characterization techniques, i.e., X‐ray diffraction, Fourier transform infrared, transmission electron microscope, N 2 physisorption, and NH 3 ‐TPD demonstrated that surface acidity, textural characteristics, and catalytic activity were greatly affected by catalyst composition. Catalyst with intermediate Zr content (0.4–0.6) had an ideal balance of weak, medium, and strong Brønsted acid sites, which resulted in complete conversion of sorbitol and higher isosorbide selectivity. 100% sorbitol conversion and 87% isosorbide selectivity were achieved with sulfated (S)‐Zr 0.5 Sn 0.5 O 2 at 220 °C within 3 h, exceeding many reported heterogeneous solid acids catalyst. A minor loss in catalyst activity was observed after four cycles, showing its potential for long‐term isosorbide production.
Dye‐sensitized solar cells are gaining recognition as a promising technology increasingly drawing the interest of a burgeoning array of IoT devices and wireless sensors, providing a solution to the escalating need for cordless power. We have chosen four organic sensitizers incorporating triphenyl imidazole and phenothiazine as double donors alongside a carboxylic acid as an anchoring group. Sensitizers have either benzothiadiazole (LG‐P6 and LG‐P8) or phenyl (LG‐P5 and LG‐P6) as an auxiliary acceptor, separated from the anchoring carboxylic acid group by an ethynyl bridge. The devices are fabricated using the I – /I 3 – redox couple and evaluated under AM1.5G and indoor light conditions. The sensitizers having benzothiadiazole displayed efficiency of 5.98% and 2.81% under 1‐sun conditions. Further, we have systematically evaluated device performance from 1000 to 100 lx WW CFL, WW LED, DL CFL, and DL LED light conditions. We observed efficiencies of 19.73% under 1000 lx WW CFL and 24.23% under 100 lx WW LED conditions using the LG‐P6 sensitizer, which is one among the highest efficiencies reported without cosensitization to the best of our knowledge. Further, we adopted interfacial charge transfer studies using different perturbation techniques to explain the photovoltaic results.
