The Experts below are selected from a list of 7284 Experts worldwide ranked by ideXlab platform
Tianshu Chu - One of the best experts on this subject based on the ideXlab platform.
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dft tddft study on the sensing mechanism of a fluorescent probe for hydrogen sulfide excited state intramolecular proton transfer coupled twisted intramolecular charge transfer
Journal of Physical Chemistry A, 2017Co-Authors: Tianshu ChuAbstract:By using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, the sensing mechanism of a fluorescent probe 2-(2-hydroxyphenyl) benzothiazole (HBT) derivative HBTPP-S for hydrogen sulfide has been thoroughly studied. The thiolysis reaction has a moderate reaction barrier of 18.40 kcal mol–1, which indicates that the hydrogen sulfide sensing process has a favorable response speed. Because of the nonradiative donor-excited photoinduced electron transfer (d-PET, fluorophore as the electron donor) from the excited HBTPP group to the electron-withdrawing 2,4-dinitrophenyl group, as well as the inhibition of the proton transfer (PT) and the excited state intramolecular proton transfer (ESIPT) process by 2,4-dinitrophenyl group, the probe HBTPP-S is essentially nonfluorescent. On the other hand, the added hydrogen sulfide induces the thiolysis of the 2,4-dinitrophenyl ether bond, and then the thiolysis product HBTPP comes into existence. The theoretically simulated potenti...
Qichu Zhang - One of the best experts on this subject based on the ideXlab platform.
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a water stable tb iii based metal organic gel mog for detection of antibiotics and explosives
Inorganic chemistry frontiers, 2018Co-Authors: Wenwe Dong, Ju Zhao, Qichu ZhangAbstract:The rapid detection of antibiotics and organic explosives has gradually garnered great attention, due to concerns about sustainability and the environment. In this work, a luminescent Tb-based metal organic gel (MOG(Tb) gel) was prepared by Al-based MOG induced in situ replacement of Al3+ with Tb3+. Remarkably, the strong emission of the post-synthesized MOG(Tb) xerogel can be quenched efficiently by using trace amounts of sulfamethazine (SMZ) and sulfadiazine (SDZ) even in the presence of other competing antibiotics. Furthermore, the MOG(Tb) xerogel has shown its application as a chemosensor for the highly selective detection of nitroaromatics such as 2,4-Dinitrophenol (2,4-DNT) and 2,6-Dinitrophenol (2,6-DNT). To further verify the recyclability of MOG(Tb), detection experiments were carried out with recovered xerogel to give a satisfactory result.
Xiaohai Yang - One of the best experts on this subject based on the ideXlab platform.
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a selective pvc membrane for di or trinitrophenol based on n n dibenzyl 3 3 5 5 tetramethylbenzidine
Analyst, 2002Co-Authors: Ronghua Yang, Kemin Wang, Li Ping Long, Winghong Chan, Xiaohai YangAbstract:A new fluorophore, N,N-dibenzyl-3,3′,5,5′-tetramethylbenzidine (NBTMB), was prepared and shown to exhibit significant and analytical usefulness for optical sensing toward 2,4-Dinitrophenol or 2,4,6-trinitrophenol (picric acid) when it was immobilized in a plasticized poly(vinyl chloride) (PVC) membrane. When the membrane was applied to aqueous nitrophenol solution, NBTMB was able to extract selectively nitrophenol into the membrane phase. Since the extraction equilibrium was accompanied by fluorescence quenching of NBTMB, the chemical recognition process could be directly translated into an optical signal. The sensor showed reversible response in the concentration range from 2.0 × 10−7 to 6.0 × 10−5 mol L−1 for the detection of 2,4-Dinitrophenol in NaOAc–HOAc buffer at pH 4.0. It also showed a fast response time (t95% < 1.5 min) when the sensor was applied to 2,4-Dinitrophenol solution at concentration levels of 5.26 × 10−6 and 2.10 × 10−5 mol L−1 alternatively. A working principle is proposed and the responses of this sensor to various kinds of nitrophenol were studied. The sensor was applied to the direct determination of 2,4-Dinitrophenol in prepared water samples and the indirect assay of the drug cinchonine and the results obtained were satisfactory.
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a renewable liquid drop sensor for di or trinitrophenol based on fluorescence quenching of 3 3 5 5 tetramethylbenzidine dihydrochloride
Analyst, 2000Co-Authors: Ronghua Yang, Kemin Wang, Dan Xiao, Xiaohai YangAbstract:A novel renewable liquid drop sensor is proposed for the execution of a sensitive, simple and rapid assay. The dynamically growing and falling drops are formed at the bottom tip of a silanized silica capillary tube connected to the end of a flow system. The feasibility of the proposed method was demonstrated by performing the fluorimetric determination of di- or trinitrophenol by using 3,3′,5,5′-tetramethylbenzidine dihydrochloride (TMB-d) as sensing reagent. The optimum analytical conditions were established. The sensor shows linear responses in the measuring ranges from 2.45 × 10−7 to 5.0 × 10−5 mol l−1 2,4-Dinitrophenol and from 1.07 × 10−7 to 8.0 × 10−6 mol l−1 2,4,6-trinitrophenol, and has detection limits of 1.0 × 10−8 mol l−1 for 2,4-Dinitrophenol and 4.0 × 10−9 mol l−1 for 2,4,6-trinitrophenol. The analysis is simple and rapid and consumes only micro-amounts of reagent and sample. The sensor was applied to the direct determination of 2,4-Dinitrophenol in synthetic water samples and the indirect assay of quinine through quantitative precipitation with 2,4,6-trinitrophenol. The results were in good agreement with those obtained by another method.
Wenwe Dong - One of the best experts on this subject based on the ideXlab platform.
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a water stable tb iii based metal organic gel mog for detection of antibiotics and explosives
Inorganic chemistry frontiers, 2018Co-Authors: Wenwe Dong, Ju Zhao, Qichu ZhangAbstract:The rapid detection of antibiotics and organic explosives has gradually garnered great attention, due to concerns about sustainability and the environment. In this work, a luminescent Tb-based metal organic gel (MOG(Tb) gel) was prepared by Al-based MOG induced in situ replacement of Al3+ with Tb3+. Remarkably, the strong emission of the post-synthesized MOG(Tb) xerogel can be quenched efficiently by using trace amounts of sulfamethazine (SMZ) and sulfadiazine (SDZ) even in the presence of other competing antibiotics. Furthermore, the MOG(Tb) xerogel has shown its application as a chemosensor for the highly selective detection of nitroaromatics such as 2,4-Dinitrophenol (2,4-DNT) and 2,6-Dinitrophenol (2,6-DNT). To further verify the recyclability of MOG(Tb), detection experiments were carried out with recovered xerogel to give a satisfactory result.
Leif L Marking - One of the best experts on this subject based on the ideXlab platform.
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salinity and temperature effects on chronic toxicity of 2 4 Dinitrophenol and 4 nitrophenol to sheepshead minnows cyprinodon variegatus
Environmental Toxicology and Chemistry, 1994Co-Authors: T K Linton, Foster L. Mayer, Tasha L Simon, Janice A Malone, Leif L MarkingAbstract:Toxicity tests (28-d early-life-stage) were conducted to determine the effects of nine combinations of salinity (15, 20, 25 ppt) and temperature (22, 27, 32°C) on the toxicity of 2,4-Dinitrophenol (2,4-DNP) and 4-nitrophenol (4-NP) to sheepshead minnows (Cyprinodon variegatus). The highest tested concentration having no observed effect (NOEC) on mortality and growth was derived weekly. The NOECs at test termination indicated that the survival and growth of fish exposed to 2,4-Dinitrophenol were not significantly affected by salinity, temperature, or the salinity temperature interaction. However, 28-d NOECs of fish surviving from 4-nitrophenol exposures were significantly affected by temperature, but the highest value exceeded the lowest by only a factor of two. The overall data suggest that variations of salinity and temperature do not change the NOEC; only the exposure time required to attain the same NOEC is altered.
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acute toxicity of 4 nitrophenol 2 4 Dinitrophenol terbufos and trichlorfon to grass shrimp palaemonetes spp and sheepshead minnows cyprinodon variegatus as affected by salinity and temperature
Environmental Toxicology and Chemistry, 1994Co-Authors: Jeri A Breckenfolse, Foster L. Mayer, Leslie E Pedigo, Leif L MarkingAbstract:The toxicities of two industrial chemicals (4-nitrophenol and 2,4-Dinitrophenol) and two organophosphate insecticides (terbufos and trichlorfon) to juvenile grass shrimp (Palaemonetes spp.) and sheepshead minnows (Cyprinodon variega-tus) were determined by static, 96-h toxicity tests in a factorial design with 12 combinations of salinity and temperature (15, 20, 25, 30 ppt × 17, 22, 27°C). Concentrations of the toxicants, including bioconcentration, were determined as appropriate by gas or liquid chromatography and the use of 14C-labeled compounds. The 96-h LC50s for 4-nitrophenol ranged from 12 to 31 mg/L and for 2,4-Dinitrophenol from 13 to 50 mg/L. Toxicity decreased as salinity increased for 4-nitrophenol and both test organisms. Toxicity decreased as salinity increased for 2,4-Dinitrophenol and sheepshead minnows, but toxicity to grass shrimp increased as salinity increased. Toxicity decreased with increased temperature for grass shrimp exposed to 2,4-Dinitrophenol and sheepshead minnows exposed to 4-nitrophenol, increased with temperature for sheepshead minnows exposed to 2,4-Dinitrophenol, and no change was observed for grass shrimp exposed to 4-nitrophenol. Bioconcentration of phenols in both test organisms increased as concentration increased. The 96-h LC50s for terbufos ranged from 3.4 to 6.6 μg/L and for trichlorfon from 6.3 to 19,300 μg/L. Terbufos and trichlorfon toxicity to grass shrimp and sheepshead minnows increased with increased temperature. BCFs for terbufos were greater in sheepshead minnows than grass shrimp, but were reversed for trichlorfon.