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Deng X, Tang Y, Song X, Liu K, Gu Z, Zhang B. Photolysis dynamics of m- and o-fluorophenol: Substitution effects on tunneling mechanism. CHEMOSPHERE 2020; 253:126747. [PMID: 32464759 DOI: 10.1016/j.chemosphere.2020.126747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
The photolysis dynamics of m-fluorophenol (m-FPhOH) and o-fluorophenol (o-FPhOH) have been investigated with time-resolved velocity map imaging (TR-VMI) and time-resolved ion-yield (TR-IY) techniques. Following excitation to the origin of S1 (ππ∗) state of m- and o-FPhOH, H atoms elimination mediated by tunneling through the potential barrier under the S1 (ππ∗)/S2 (πσ∗) conical intersection (CI) has been observed as a Gaussian feature signal centered at a total kinetic energy release (TKER) of ∼6000 cm-1 for both molecules. The quantum tunneling mechanism has been identified as the main decay pathway of S1 state for m-FPhOH, and the tunneling lifetime of 2.1 ns has been obtained from the TR-VMI measurements of H fragments. This tunneling mechanism is further confirmed by the studies on the selective O-H deuterated species, m-FPhOD, and consolidated by our theoretical calculations. However, the photolysis dynamics is quite different for the photoexcited o-FPhOH. The much lower yield of the H atoms originating from tunneling hinders the extraction of a reliable tunneling lifetime for o-FPhOH. Our theoretical calculations exhibit a broader and higher potential barrier exists beneath the S1/S2 CI of o-FPhOH, which increase the difficulty for tunneling. Furthermore, the special existence of intramolecular hydrogen bond in o-FPhOH is probably also the key factor that affects the tunneling rate, which would restrict the O-H stretch motion.
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Affiliation(s)
- Xulan Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xinli Song
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kai Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenfei Gu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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Flow-based method for the determination of biomarkers urea and ammoniacal nitrogen in saliva. Bioanalysis 2020; 12:455-465. [DOI: 10.4155/bio-2020-0036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aim: Salivary urea and ammonium levels are potential biomarkers for chronic kidney disease. A fast and efficient assessment of these compounds in the saliva of healthy and diseased individuals may be a useful tool to monitor kidney function. Materials & methods: Ammonium ions were measured with an ammonia selective electrode after conversion to ammonia gas. A urease reactor was incorporated in the manifold to hydrolyze urea to ammonium, thereby providing values of ammonia from both urea and ammonium ions in the sample. The accuracy of the method was assessed by comparison with a commercially available kit for urea and ammonium determination. Conclusion: A sequential injection method for the biparametric determination of salivary urea and ammonium employing a single sequential injection manifold was successfully applied to samples collected from both healthy volunteers and chronic kidney disease patients.
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Chango G, Palacio E, Cerdà V. Potentiometric chip-based multipumping flow system for the simultaneous determination of fluoride, chloride, pH, and redox potential in water samples. Talanta 2018; 186:554-560. [DOI: 10.1016/j.talanta.2018.04.087] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/27/2018] [Accepted: 04/26/2018] [Indexed: 11/16/2022]
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Rocha DP, Anjos GTC, Neri TS, Tronto J, Pinto FG, Silva SG, Coelho NMM. A flow injection procedure using Layered Double Hydroxide for on line pre-concentration of fluoride. Talanta 2017; 178:102-108. [PMID: 29136791 DOI: 10.1016/j.talanta.2017.09.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 09/03/2017] [Accepted: 09/06/2017] [Indexed: 10/18/2022]
Abstract
This work showed a flow system designed with solenoid valves for preconcentration of fluoride using SPADNS method in water samples. The analyte was preconcentrated in a mini-column coated with Layered Double Hydroxides (LDH) used as adsorbent. Then, the fluoride ions were eluted with 0.5molL-1 sodium hydroxide and determined by spectrophotometry. The variables that affect the system such adsorbent mass, type of eluent, solutions flow rate, reagent concentration and pH effect were critically evaluated. Under optimized conditions, the detection limit, coefficient of variation, linear range and preconcentration factor were estimated at 15µgL-1 (99.7% confidence level), 0.8% (500µgL-1, n = 10), 50-500µgL-1 and 10, respectively. The accuracy of the method was evaluated by analysis of ALPHA APS 1076 (Simulated Rain Water) certified material, the values were not significantly different at a 95% level of confidence. The method was applied for fluoride determination in water samples and the levels found were below the maximum values established by Brazilian environmental and health legislations.
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Affiliation(s)
- Diego P Rocha
- Federal University of Uberlândia, Institute of Chemistry, Avenue João Naves de Ávila, 2121, Santa Mônica, Uberlândia, MG CEP 38400-902, Brazil
| | - Gabriel T C Anjos
- Federal University of Uberlândia, Institute of Chemistry, Avenue João Naves de Ávila, 2121, Santa Mônica, Uberlândia, MG CEP 38400-902, Brazil
| | - Thais S Neri
- Federal University of Uberlândia, Institute of Chemistry, Avenue João Naves de Ávila, 2121, Santa Mônica, Uberlândia, MG CEP 38400-902, Brazil
| | - Jairo Tronto
- Federal University of Viçosa, Campus de Rio Paranaíba, Institute of Exact and Technological Sciences, Rodovia MG-230 - Km 8, Rio Paranaíba, MG CEP 38810-000, Brazil
| | - Frederico G Pinto
- Federal University of Viçosa, Campus de Rio Paranaíba, Institute of Exact and Technological Sciences, Rodovia MG-230 - Km 8, Rio Paranaíba, MG CEP 38810-000, Brazil
| | - Sidnei G Silva
- Federal University of Uberlândia, Institute of Chemistry, Avenue João Naves de Ávila, 2121, Santa Mônica, Uberlândia, MG CEP 38400-902, Brazil
| | - Nívia M M Coelho
- Federal University of Uberlândia, Institute of Chemistry, Avenue João Naves de Ávila, 2121, Santa Mônica, Uberlândia, MG CEP 38400-902, Brazil.
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Yahyavi H, Kaykhaii M, Mirmoghaddam M. Recent Developments in Methods of Analysis for Fluoride Determination. Crit Rev Anal Chem 2016; 46:106-21. [PMID: 26460519 DOI: 10.1080/10408347.2014.985814] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
This review covers current analytical techniques, instruments, and methodologies used in the analysis of fluoride in various matrices. Our comprehensive literature search showed that there is no recently published review article about analytical methodologies for fluoride. In this review, we explore chromatographic, spectroscopic, and electrochemical innovations appearing in the recent literature.
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Affiliation(s)
- Hossein Yahyavi
- a Department of Chemistry , Faculty of Sciences, University of Sistan and Baluchestan , Zahedan , Iran
| | - Massoud Kaykhaii
- a Department of Chemistry , Faculty of Sciences, University of Sistan and Baluchestan , Zahedan , Iran
| | - Majid Mirmoghaddam
- a Department of Chemistry , Faculty of Sciences, University of Sistan and Baluchestan , Zahedan , Iran
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Proposed flow system for spectrophotometric determination of fluoride in natural waters. Talanta 2013; 105:69-74. [DOI: 10.1016/j.talanta.2012.11.071] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 11/26/2012] [Accepted: 11/26/2012] [Indexed: 11/21/2022]
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