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In this work, a series of porous terpolymers with degrees of crosslinking at 30-65% were synthesized by suspension polymerization. [Fe.sub.3][O.sub.4] nanoparticles were used to modify the porous terpolymer with degree of crosslinking at 30%. The resulting terpolymers with mean pore size of 10-30 nm were used as supports for immobilization of cellulases through covalent bondings. The Fourier transform infrared spectroscopy and thermal gravity analysis measurements demonstrated that cellulases were immobilized onto the porous terpolymers. The effects of pH and temperature on enzyme activity were investigated in acetate buffer medium by hydrolysis of sodium carboxymethyl celluloses. The reusability of immobilized cellulases was also investigated. The result showed that immobilized cellulases exhibited higher residual activities and enzyme activities than free cellulases in wide ranges of pH and temperature. We also found that the reusability of cellulases immobilized on terpolymers with magnetism was better than that of cellulases immobilized on terpolymers without magnetism., INTRODUCTION Cellulase is an important complex enzyme in biological system [1] and widely used in many fields including bioenergy, food, animal feed, textile, paper, and pulping [2-5]. However, it is [...]

Four new xanthene-based fluorescent probes have been devised and synthesized. These probes were well characterized by 1H NMR, 13C NMR and HRMS. UV-vis absorption and fluorescence spectroscopy indicated that these probes show high selectivity and sensitivity towards Hg2+ in the presence of various cations, anions and amino acids in PBS buffer solution containing DMSO/H2O (1 : 1, v/v). The detection limits of the probes for Hg2+ were found to be 10.4, 12.5, 16.2 and 15.4 nM, respectively. The four probes were successfully applied for the detection of Hg2+ in a strip test. Among them, probe 4 was successfully applied for the detection of Hg2+ in biological cells. [ABSTRACT FROM AUTHOR]

A new phenothiazine‐based sensor PHE‐Ad for monitoring Hg2+ has been designed and synthesized based on the intramolecular charge transfer (ICT) mechanism. The probes were characterized by FTIR, 1H NMR, and HRMS, and their optical properties were detected by UV and FL. It's showed the probes detection of Hg2+ compared to other metal ions (Mg2+, Cu2+, Hg2+, Ag+, Co2+, Cr3+, Al3+, Ni2+, Zn2+, Ca2+, Fe3+, Fe2+, K+, Na+, and Cd2+) based on the test results. Besides, the detection limits were determined to be 2.12 × 10−8 M through the standard curve plot. In addition, sensor PHE‐Ad shows high selectivity and sensitivity for Hg2+ with a fast response in a suitable pH range. Furthermore, taking into account its good "turn‐on" fluorescent sensing behavior and low cell cytotoxicity, PHE‐Ad was successfully applied to detect and image Hg2+ in real water samples and living cells, which shows great potentials for application in environmental and biological systems. [ABSTRACT FROM AUTHOR]

Two novel colorimetric and fluorescent probes 2-(1,3-dithiolanes)-10-ethyl phenothiazine (PHE-Ed) and 2-(1,3-dithianes)-10-ethyl phenothiazine (PHE-Pd) based on phenothiazine were successfully synthesized, and their structure was confirmed by NMR and high resolution mass spectra. Fluorescence investigations revealed that the synthesized probes could be used for the selective detection of Hg2+, which was accompanied with an obvious color change from colorless to light yellow. The applicable ability of the two probes was investigated by a series of competitive experiments, solid colorimetric experiments, and applied experiments, which proved that these probes showed high sensitivity and great potential to detect Hg2+ in environmental analysis systems. Furthermore, the detection mechanism of the probes was investigated by FT-IR spectra and NMR spectra, and the results indicated that the detection of Hg2+ was accomplished through the Hg2+-promoted deprotection of thioacetal. [ABSTRACT FROM AUTHOR]

Two novel pyrazole-based chemosensors Pry-Flu and Pry-R6G were successfully synthesized, and their structures were confirmed by NMR spectroscopy and high-resolution mass spectroscopy (HRMS). The sensors Pry-Flu and Pry-R6G showed high selectivity and sensitivity toward Ni2+ and Al3+ over other competitive metal ions, respectively. Fluorescence investigation revealed that the sensor Pry-Flu could selectively coordinate with Ni2+ with a color change from colorless to orange-yellow, and the sensor Pry-R6G could be used for the specific detection of Al3+ with a color change from colorless to pink in mixed solvent (DMF/H2O, 1/99, v/v). In addition, the detection limits for Al3+ and Ni2+ were found to be as low as 2.61 × 10−8 and 1.87 × 10−8 M, respectively. The stoichiometric ratio of sensors toward the Ni2+/Al3+ ions was determined to be 1 : 1. The sensors Pry-Flu and Pry-R6G were also found to have a wide pH range (4–12) and short response time (1–3 min). Furthermore, the sensing mechanism was proposed based on chelation-enhanced fluorescence (CHEF) and investigated in detail by fluorescence spectroscopy, 1H NMR titrations and FT-IR. [ABSTRACT FROM AUTHOR]