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Li Z, Wang M, Yang J, Hong B, Lai Y, Li J. A quantitative analysis method of complex sulfide components for understanding initial capacity degradation mechanism in lithium-sulfur batteries. J Colloid Interface Sci 2024; 662:1086-1095. [PMID: 38365515 DOI: 10.1016/j.jcis.2024.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/21/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Lithium-sulfur (Li-S) batteries are a strong contender for the new-generation battery system to meet the growing energy demand due to their significantly high energy density (2600 Wh/kg) and cost-effectiveness. However, the practical operating conditions yield an initial capacity of less than 80 % of the theoretical capacity, resulting in a limited lifespan and hindering broader application. What's worse, current mechanism, especially the evolution process of sulfides for the initial capacity degradation is not clear due to the practical difficulties of effective separation and detection of sulfur-containing components. Herein, we have developed an instrumental analysis method enabling graded leaching and quantitative determination of sulfur-containing components. This technology achieves a detection precision surpassing 99.11 %, addressing the inherent deficiency in calculating sulfur-containing components using the decrement method. Applying this method reveals that the presence of lithium polysulfides in the electrolyte (26.34 wt%) after discharging is the primary factor causing insufficient capacity utilization in Li-S batteries. This work not only demonstrates the unique behavior of Li-S batteries at high sulfur loading but also provides a systematic evaluation method to guide further research on high-energy-density batteries, and provides theoretical and technical support to promote the development of high-energy, long-life Li-S batteries.
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Affiliation(s)
- Zhaoyang Li
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China
| | - Mengran Wang
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Engineering Research Centre of Advanced Battery Materials, The Ministry of Education, Changsha 410083, Hunan, China; Hunan Provincial Key Laboratory of Nonferrous Value-added Metallurgy, Changsha 410083, Hunan, China.
| | - Jiewei Yang
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China
| | - Bo Hong
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Engineering Research Centre of Advanced Battery Materials, The Ministry of Education, Changsha 410083, Hunan, China; Hunan Provincial Key Laboratory of Nonferrous Value-added Metallurgy, Changsha 410083, Hunan, China.
| | - Yanqing Lai
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Engineering Research Centre of Advanced Battery Materials, The Ministry of Education, Changsha 410083, Hunan, China; Hunan Provincial Key Laboratory of Nonferrous Value-added Metallurgy, Changsha 410083, Hunan, China
| | - Jie Li
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Engineering Research Centre of Advanced Battery Materials, The Ministry of Education, Changsha 410083, Hunan, China; Hunan Provincial Key Laboratory of Nonferrous Value-added Metallurgy, Changsha 410083, Hunan, China
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2
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Kounbach S, Laassiri S, Moutaoukil Z, Benzaouia A, Benhida R. Improvement of the characterization uncertainty of a matrix-certified reference material for accurate measurement of H 2SiF 6 mass fraction in industrial fluorosilicic acid by using a direct measurement procedure. ANAL SCI 2023; 39:1865-1873. [PMID: 37418124 DOI: 10.1007/s44211-023-00391-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023]
Abstract
The role of metrology in the industrial and manufacturing sectors is of paramount importance to ensure informed decision-making whether for product quality control, process monitoring and R&D activities. However, to guarantee the quality and reliability of analytical measurements, the development and use of appropriate reference materials (CRMs) is essential. In particular, certified reference materials (CRMs) are extensively used to validate analytical methods in a multitude of applications, measure uncertainty, improve the accuracy of measurement data, as well as to establish the meteorological traceability of analytical results. In this paper, we report the improvement of the characterization uncertainty of an in-house matrix reference material by direct determination of the concentration of fluorosilicic acid recovered from the fertilizers production industry. The certified reference material was characterized by the potentiometric method as a novel and direct approach for the determination of H2SiF6 concentration and the results were compared against a reference measurement procedure based on molecular absorption spectrophotometry (UV-VIS). The approach adopted in the work resulted in the improvement of the uncertainty of the CRM by decreasing the characterization uncertainty, which constitutes the major contribution to the overall uncertainty. The newly obtained characterization combined standard uncertainty was 2.0 g.kg-1, which gives an expanded uncertainty (k = 2 with a confidence interval of 95%) of the CRM of 6.3 g.kg-1 instead of 11.7 g.kg-1 reported in previous works. This improved CRM can be used to improve the uncertainty of the analytical methods used for the determination of H2SiF6 mass fraction and, therefore, to improve the accuracy of measurement data.
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Affiliation(s)
- Said Kounbach
- Department of Chemical and Biochemical Sciences, Green Process Engineering CBS, Mohammed VI Polytechnic University, 43150, Ben Guerir, Morocco.
- Institut de Chimie de Nice, UMR7272, Université Côte d'Azur, 06108, Nice, France.
| | - Said Laassiri
- Department of Chemical and Biochemical Sciences, Green Process Engineering CBS, Mohammed VI Polytechnic University, 43150, Ben Guerir, Morocco
| | - Zakaria Moutaoukil
- Department of Chemical and Biochemical Sciences, Green Process Engineering CBS, Mohammed VI Polytechnic University, 43150, Ben Guerir, Morocco
- Institut de Chimie de Nice, UMR7272, Université Côte d'Azur, 06108, Nice, France
| | - Abderrahim Benzaouia
- Department of Chemical and Biochemical Sciences, Green Process Engineering CBS, Mohammed VI Polytechnic University, 43150, Ben Guerir, Morocco
- Institut de Chimie de Nice, UMR7272, Université Côte d'Azur, 06108, Nice, France
| | - Rachid Benhida
- Department of Chemical and Biochemical Sciences, Green Process Engineering CBS, Mohammed VI Polytechnic University, 43150, Ben Guerir, Morocco.
- Institut de Chimie de Nice, UMR7272, Université Côte d'Azur, 06108, Nice, France.
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3
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Kosmulski M. The pH dependent surface charging and points of zero charge. X. Update. Adv Colloid Interface Sci 2023; 319:102973. [PMID: 37573830 DOI: 10.1016/j.cis.2023.102973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/15/2023]
Abstract
Surfaces are often characterized by their points of zero charge (PZC) and isoelectric points (IEP). Different authors use these terms for different quantities, which may be equal to the actual PZC under certain conditions. Several popular methods lead to results which are inappropriately termed PZC. This present review is limited to zero-points obtained in the presence of inert electrolytes (halides, nitrates, and perchlorates of the 1st group metals). IEP are reported for all kinds of materials. PZC of metal oxides obtained as common intersection points of potentiometric curves for 3 or more ionic strengths (or by means of equivalent methods) are also reported, while the apparent PZC obtained by mass titration, pH-drift method, etc. are deliberately neglected. The results published in the recent publications and older results overlooked in the previous compilations by the same author are reported. The PZC/IEP are accompanied by information on the temperature and on the nature and concentration of supporting electrolyte (if available). The references to previous reviews by the same author allow to compare the newest results with the PZC/IEP of similar materials from the older literature.
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Affiliation(s)
- Marek Kosmulski
- Lublin University of Technology, Nadbystrzycka 38, PL-20618 Lublin, Poland.
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4
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Mora MM, Ismail NS, Zaazaa HE, Boltia SA. Electrochemically-selective electrode for quantification of dorzolamide in bulk drug substance and dosage form. BMC Chem 2023; 17:103. [PMID: 37605267 PMCID: PMC10440925 DOI: 10.1186/s13065-023-01021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 08/09/2023] [Indexed: 08/23/2023] Open
Abstract
Three smart carbon paste electrodes were fabricated to quantify dorzolamide hydrochloride DRZ, including conventional carbon paste I, modified carbon paste embedding Silica II, and modified carbon paste embedding β-cyclodextrin III. This study is based on the insertion of DRZ with phosphomolybdic acid to create an electroactive moiety dorzolamide-phosphomolybdate ion exchanger using a solvent mediator dibutyl phthalate. The three constructed carbon paste electrodes displayed Nernstian responses and linear concentration ranges with lower detection limits. The vital performance of the created electrodes was verified in relation to various parameters. The electrodes enhance the selective determination of DRZ in the presence of inorganic ions, a co-formulated drug in the dosage form timolol maleate, and the excipient benzalkonium chloride. The modified carbon paste electrode including Silica was utilized to detect DRZ in ophthalmic eye drop form utilizing the direct calibration curve and potentiometric titration methods. Satisfactory findings were achieved by comparing them to other reported methods.
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Affiliation(s)
- Mai M Mora
- Egyptian Drug Authority (EDA), Giza, Egypt
| | | | - Hala E Zaazaa
- Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, 11562, Egypt
| | - Shereen A Boltia
- Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, 11562, Egypt.
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5
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Hu R, Fan Z, Liu Z, Huang T, Wen G. Experimental study on the effects of different factors on the crystallization rate and products of Mn-Ca co-crystallization. Environ Sci Pollut Res Int 2023; 30:13521-13531. [PMID: 36138290 DOI: 10.1007/s11356-022-23113-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Calcium and manganese are common ions that pollute drinking water and, therefore, ingestion may seriously harm human health. However, despite its importance, few studies into the synergistic removal of calcium and manganese have been reported. Calcium and manganese have similar chemical properties and, consequently, can be removed by co-crystallization, as the exact crystalline phase formed by this process and the process rate depend on the pH, the dissolved oxygen (DO) content, and the concentrations of the component ions. In this work, we experimentally studied the co-crystallization of Mn and Ca using an automatic potentiometric titrator. We found that the concentration of Mn2+ can be reduced from 3.0 to <0.1 mg/L by the co-crystallization of Mn and Ca at pH 10.5 and a DO content of 8.5 mg/L. In addition, the crystallizations of Ca and Mn are mutually inhibitory; the crystallization process of Mn is obviously divided into two stages: crystal nucleation and crystal growth. Increasing the pH, decreasing the DO content, and decreasing the Mn ion concentration increase the rate of CaCO3 crystallization, whereas the opposite changes increase the rate of Mn crystallization. Furthermore, Mn-Ca co-crystallization leads to the formation of various substances, including single crystals (CaCO3/MnCO3), mixed crystals (CaMnCO3), and Mn oxides (MnxOy/Mn(OH)O). Our findings regarding the effects, precipitation rates, and precipitation mechanisms of Mn-Ca co-crystallization serve as an important guide for the optimization and control of Mn-Ca co-crystallization processes.
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Affiliation(s)
- Ruizhu Hu
- School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an, 710055, People's Republic of China
- Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
| | - Zexin Fan
- School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an, 710055, People's Republic of China
- Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
| | - Zenan Liu
- School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an, 710055, People's Republic of China
| | - Tinglin Huang
- School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China.
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an, 710055, People's Republic of China.
- Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China.
| | - Gang Wen
- School of Environment and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an, 710055, People's Republic of China
- Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China
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Deng X, Chen B, Chen Y, Jiang L, Hu Y, Yang Y, Rong X, Peng L, Zeng Q. Flag leaf cell wall functional groups and components play a crucial role in the accumulation and translocation of Cd in rice grain via foliage application of humic acid. Ecotoxicol Environ Saf 2022; 239:113658. [PMID: 35598444 DOI: 10.1016/j.ecoenv.2022.113658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 04/29/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Devising a low-cost and effective strategy to reduce Cd contamination of brown rice is critical to achieve the safe production of rice grain for human consumption. Accordingly, here field experiments were conducted at two sites to evaluate the effects of applying humic acid (HA) to foliage twice, at the booting and full heading stage, on diminishing the translocation of cadmium (Cd) into rice grains. Besides measuring the Cd subcellular distribution in the flag leaf and the polysaccharide composition of the cell wall, the latter's types and concentrations of functional groups were quantitatively analyzed by potentiometric titration and fitted by a surface complexation model. The results demonstrated that applying HA to leaves not only increased the rice yield but also reduced the Cd concentration in brown rice by 35.48-39.74% when using an application rate of just 600 g/ha. The HA treatment augmented Cd fixation in flag leaves, reduced the Cd translocation to rachis and brown rice, and increased the subcellular distribution of Cd in flag leaf cell wall. Furthermore, the Cd concentration in the pectin and hemicellulose 1 of cell wall increased by 33.00% and 25.73%, respectively. Besides those effects, foliar spraying of HA induced a greater abundance of carboxyl, hydroxyl, and amino groups on the cell wall, allowing for more sites to be involved in the binding of Cd, thereby promoting the immobilization of Cd in the flag leaf, and ultimately reducing the remobilization of Cd into the grain. Thus, foliage application of HA may offer a promising and cost-effective tactic for the remediation and continued use of Cd-contaminated paddy soils. CAPSULE: Foliage application of humic acid promoted the deposition of Cd in the cell wall of rice flag leaf, thereby enhancing the immobilization of Cd and ultimately reducing the remobilization of Cd into the grain.
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Affiliation(s)
- Xiao Deng
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Bin Chen
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Yixuan Chen
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Lu Jiang
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Yumin Hu
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Yang Yang
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Xiangmin Rong
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Liang Peng
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Qingru Zeng
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China.
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7
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Gupta DK, Neupane S, Yadav HC, Subedi V, Singh S, Yadav RJ, Das AK, Yadav B, Nakarmi KB, Karki N, Yadav AP. Trace level monitoring of Cu(II) ion using CuS particles based membrane electrochemical sensor. Heliyon 2021; 7:e07167. [PMID: 34141928 PMCID: PMC8187969 DOI: 10.1016/j.heliyon.2021.e07167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/10/2021] [Accepted: 05/26/2021] [Indexed: 11/30/2022] Open
Abstract
Cu(II) monitoring is a matter of great interest to researchers due to its toxicity and adverse environmental effects. Among different methods for detecting Cu(II), ion-selective electrode (ISE) is more advantageous as they are low-cost, easy to fabricate, and highly selective. Here, we report a simple, inexpensive, and reproducible procedure for the fabrication of Cu(II) ion-selective electrodes using CuS particles and polyvinyl chloride (PVC) as a matrix. CuS particles, obtained by chemical precipitation, were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), and energy-dispersive X-Ray spectroscopy (EDX). Optimization of the membrane compositions was done to get a well-behaved sensor by varying amounts of CuS, PVC, and acetophenone (AP). A membrane composition of 0.4 g CuS, 0.5 g PVC, and 1.0 mL AP in 5.0 mL tetrahydrofuran (THF) gave a Nernstian slope of 27.31 mV per decade change of Cu(II) ion over a wide range of concentration down to 64 ppb (1 × 10−6 M). The sensor gave a fast response time of 25 s, and it indicated the endpoint in a potentiometric titration of Cu(II) with standard EDTA solution. A pH-independent potential response was obtained in the pH 4.0–6.0.
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Affiliation(s)
- Dipak Kumar Gupta
- Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Shova Neupane
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
- Corresponding author.
| | | | - Vivek Subedi
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Sanjay Singh
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | | | - Anju Kumari Das
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Brahamdeo Yadav
- Ramsworup Ramsagar Multiple Campus, Tribhuvan University, Janakpur, Nepal
| | | | - Nabin Karki
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Amar Prasad Yadav
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
- Corresponding author.
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Dadras A, Rezvanfar MA, Beheshti A, Naeimi SS, Siadati SA. An Urgent Industrial Scheme both for Total Synthesis, and for Pharmaceutical Analytical Analysis of Umifenovir as an Anti-Viral API for Treatment of COVID-19. Comb Chem High Throughput Screen 2021; 25:838-846. [PMID: 33538665 DOI: 10.2174/1386207324666210203175631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND This paper is prepared to reveal about an urgent industrial scheme for a fast and facile total synthesis of umifenovir (arbidol) (by one-pot stages) as an antiviral agent for treating 2019-nCoV virus via inhibiting its viral replication in the human cells. As COVID-19, takes thousands of lives all around the world, it seems that the medicinal resources would not be enough to supply billions of peoples, currently living on the planet earth. Thus, this pandemic and its subsequent impacts on the natural order of our life, would be one of the most important threats against the entire human race. Aims & Objective: Due to this, in this project, we have made attempts to find an operative approach for synthesizing this compound as an active pharmaceutical ingredient (API), which showed it could be effective in inhibiting the newly emerged coronavirus. RESULTS The designed scheme uses relatively cheap precursors, and contains one pot stages, instead of seven time consuming, and more costly, linear steps. Also, it is tried to use safe and cheap solvents like water, and ethanol, instead of toxic ones like methanol, and pyridine which could cause rejection of the API in the organic volatile impurities (OVI) test of pharmacopeia analysis, as well as increasing the concern of inflammability, explosive, and carcinogenic properties of those common solvents. CONCLUSION The most important pharmaceutical analytical methods containing OVI test (mainly ethanol (about 171 ppm) much lower than the limits, by gas chromatography-Flame Ionization Detector (GC-FID) instrument), Assay content (about 99.6% by potentiometric titration), and related purity analysis (by High performance liquid chromatography-Ultraviolet Detector (HPLC-UV)) (about 99.8%) were performed and described to give a more clear industrial scheme.
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Affiliation(s)
- Akbar Dadras
- R&D Department, Tofigh Daru Research and Engineering Company, TPICO, Tehran, . Iran
| | - Mohammad Amin Rezvanfar
- Toxicology and Diseases Group (TDG), Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, . Iran
| | | | | | - Seyyed Amir Siadati
- R&D Department, Tofigh Daru Research and Engineering Company, TPICO, Tehran, . Iran
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9
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Abstract
Redox titration of flavoproteins allows to detect and analyze (1) the determinants of the stabilization of individual redox forms of the flavin by the protein; (2) the binding of the redox-active cofactor to the protein; (3) the effects of other components of the systems (such as micro- or macromolecular interactors) on parameters 1 and 2; (4) the pattern of electron flow to and from the flavin cofactor to other redox-active chemical species, including those present in the protein itself or in its physiological partners. This overview presents and discusses the fundamentals of the methodological approaches most commonly used for these purposes, and illustrates how data may be obtained in a reliable way, and how they can be read and interpreted.
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Affiliation(s)
- Francesco Bonomi
- Section of Chemical and Biomolecular Sciences, DeFENS, University of Milan, Milan, Italy.
| | - Stefania Iametti
- Section of Chemical and Biomolecular Sciences, DeFENS, University of Milan, Milan, Italy
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10
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Xu X, Woźniczka M, Van Hecke K, Buyst D, Mara D, Vervaet C, Herman K, Wynendaele E, Deconinck E, De Spiegeleer B. Structural study of L-ascorbic acid 2-phosphate magnesium, a raw material in cell and tissue therapy. J Biol Inorg Chem 2020; 25:875-885. [PMID: 32719971 DOI: 10.1007/s00775-020-01801-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 06/29/2020] [Indexed: 02/02/2023]
Abstract
L-ascorbic acid 2-phosphate magnesium (APMg) salt is a vitamin C derivative frequently used as a raw material in cell and tissue therapy. APMg is not only used as a replacement of the unstable ascorbate, but also shows additional cell-biological functionalities. However, its unknown structural characteristics hamper the mechanistic elucidation of its biological role. Therefore, different techniques were applied for APMg structure characterization. Firstly, the stoichiometric composition was characterized by its solvent, ligand and magnesium content. No crystals of APMg could be obtained; however, a single crystal of APNa, the sodium salt of l-ascorbic acid 2-phosphate, was successfully obtained and its crystal structure was elucidated. FT-IR was applied to further clarify the structure of solid APMg. Finally, the structure of APMg in aqueous solution was explored by potentiometric titration as well as FT-IR.
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Affiliation(s)
- Xiaolong Xu
- Drug Quality and Registration (DruQuaR) Group, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Magdalena Woźniczka
- Department of Physical and Biocoordination Chemistry, Faculty of Pharmacy, Medical University of Łódź, Muszyńskiego 1, 90-151, Łódź, Poland
| | - Kristof Van Hecke
- Department of Chemistry, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium
| | - Dieter Buyst
- Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium
| | - Dimitrije Mara
- Department of Chemistry, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium
| | - Chris Vervaet
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Karen Herman
- Drug Quality and Registration (DruQuaR) Group, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Evelien Wynendaele
- Drug Quality and Registration (DruQuaR) Group, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Eric Deconinck
- Section of Medicines and Health Products, Scientific Direction Chemical and Physical Health Risks, Sciensano, Juliette Wytsmanstreet 14, 1050, Brussels, Belgium
| | - Bart De Spiegeleer
- Drug Quality and Registration (DruQuaR) Group, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
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11
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Costa TG, Meurer L, Micke GA, Gonçalves S, Szpoganicz B, Mangrich AS. Potentiometric titration of microhydrolysis products of oils: A new low-cost methodology and investment for the analysis of oil binders present in works of art. Talanta 2020; 212:120736. [PMID: 32113528 DOI: 10.1016/j.talanta.2020.120736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 11/25/2022]
Abstract
The analysis of oil paints present in historical paintings is commonly carried out for research, authenticity and forensic purposes. This paper proposes potentiometric titration and calculation of the fatty acids concentrations with the aid of the Best7 program as an alternative technique to characterize the oil binders used in works of art. The method involves determining the ratio between the levels of palmitic (P) and stearic (S) acids present in the microhydrolysis products of commercial oil binders and paints. The microhydrolysis products were characterized, using FTIR spectroscopy, by displacement of the carbonyl band and the pKa values for the C16 and C18 in the system studied were determined. The P/S ratios found for the microhydrolysis products of linseed, palm and nut oils were 1.65, 5.91 and 2.42, respectively. For the commercial paints analyzed, values ranging from 1.34 to 1.98 were obtained, characterizing the presence of linseed oil. The values were confirmed by GC-MS and are in agreement with those reported in the literature for the oils investigated in this study.
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Affiliation(s)
- Thiago G Costa
- Laboratory of Materials, Atelier for the Conservation-Restoration of Movable Cultural Heritage, FundaçãoCatarinense de Cultura (Santa Catarina Culture Foundation), 88025-200, Florianópolis, SC, Brazil; Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil.
| | - Lino Meurer
- Laboratory of Materials, Atelier for the Conservation-Restoration of Movable Cultural Heritage, FundaçãoCatarinense de Cultura (Santa Catarina Culture Foundation), 88025-200, Florianópolis, SC, Brazil; Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil
| | - Gustavo Amadeu Micke
- Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil
| | - Samantha Gonçalves
- Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil
| | - Bruno Szpoganicz
- Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil
| | - Antônio S Mangrich
- Department of Chemistry, Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil
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12
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Karimvand SK, Nguyen XA, Abdollahi H, Burns R, Clifford S, Maeder M, McCann N, Neuhold YM, Puxty G. Activity-based analysis of potentiometric pH titrations. Anal Chim Acta 2019; 1075:49-56. [PMID: 31196423 DOI: 10.1016/j.aca.2019.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/23/2019] [Accepted: 05/01/2019] [Indexed: 11/26/2022]
Abstract
The discrepancy between concentrations and activities is a predicament well known to the analytical chemist. Because of the difficulty of determining activity coefficients, the standard technique for quantitative equilibrium studies is to work under a particular 'constant ionic strength' by adding an excess of an inert salt. Under such conditions, activity coefficients are approximately constant and can be taken into the equilibrium constants which are defined for the chosen ionic strength (I). Here we propose a fundamentally different approach. Throughout the numerical analysis of the titration data, activity coefficients for all individual species are approximated by well-known equations based on the work of Debye-Hückel. The computational analysis of the measurements strictly obeys the law of mass conservation and obeys the law of mass action only approximately. The main novelty is that now the addition of inert salts is no longer required and measurements are done at minimal I. Consequently, the thermodynamic equilibrium constants are now determined much more robustly based on experiments taken at low I. The approach has been tested and validated with the two very well investigated 3-protic phosphoric and citric acids. In summary: the technique of artificially keeping ionic strength constant has been replaced by improved computational analysis.
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Affiliation(s)
- Somaiyeh Khodadadi Karimvand
- Department of Chemistry, The University of Newcastle, University Drive, Newcastle, Australia; Department of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
| | - Xuan Anh Nguyen
- Department of Chemistry, The University of Newcastle, University Drive, Newcastle, Australia
| | - Hamid Abdollahi
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
| | - Robert Burns
- Department of Chemistry, The University of Newcastle, University Drive, Newcastle, Australia
| | - Sarah Clifford
- Department of Chemistry, The University of Newcastle, University Drive, Newcastle, Australia
| | - Marcel Maeder
- Department of Chemistry, The University of Newcastle, University Drive, Newcastle, Australia.
| | | | - Yorck-Michael Neuhold
- Eawag, Swiss Federal Institute of Aquatic Science & Technology, Dübendorf, Switzerland
| | - Graeme Puxty
- CSIRO Energy, 10 Murray Dwyer Circuit, Mayfield West, NSW, 2304, Australia
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13
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Ali Ahmad M, Zajac J, Prelot B. The effect of chelating anions on the retention of Co(II) by γ-alumina from aqueous solutions under the unadjusted pH condition of supported catalyst preparation. J Colloid Interface Sci 2019; 535:182-194. [PMID: 30293044 DOI: 10.1016/j.jcis.2018.09.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/21/2018] [Accepted: 09/26/2018] [Indexed: 10/28/2022]
Abstract
This study analyzes the effect of the addition of acetate, citrate, and nitrilotriacetate anions on the retention of Co(II) cations by the γ-alumina surface in view of the preparation of alumina supported cobalt catalysts. The emphasis was placed on the way the Co(II) species attach to the solid surface when adsorbed from aqueous solutions under the unadjusted pH condition. The individual adsorption isotherms onto γ-Al2O3 support for cobalt and a given ligand were determined by following the solution depletion method in single-solute and bi-solute systems. These adsorption data were supplemented by the results of potentiometric titrations. In the case of bi-solute systems, the adsorption procedures allowed either co-impregnation of γ-alumina with equimolar solutions of cobalt and ligand salts or pre-impregnation of γ-alumina with the ligand anions and the subsequent adsorption of cobalt. Changes in the pH of the equilibrium solid-liquid suspension were also monitored along the adsorption isotherms. The adsorption of Co(II) onto γ-Al2O3 in the presence of acetate and nitrilotriacetate led to the formation of the type A (i.e., solid-metal-ligand) ternary complexes. The use of citrate anions together with Co(II) cations was shown to improve the impregnation process through the formation of ternary complexes of type B (i.e., solid-ligand-metal). The comparison with a system containing tricarballylate anions allowed concluding that the presence of the hydroxyl group in the citrate anion enhanced its affinity for the alumina surface by contributing to the inner-sphere character of its surface-bound complexes.
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Affiliation(s)
- Mouhamad Ali Ahmad
- Institut Charles Gerhardt, UMR-5253 CNRS-UM-ENSCM, Université de Montpellier, Place E. Bataillon, F-34095 Montpellier cedex 5, France
| | - Jerzy Zajac
- Institut Charles Gerhardt, UMR-5253 CNRS-UM-ENSCM, Université de Montpellier, Place E. Bataillon, F-34095 Montpellier cedex 5, France
| | - Benedicte Prelot
- Institut Charles Gerhardt, UMR-5253 CNRS-UM-ENSCM, Université de Montpellier, Place E. Bataillon, F-34095 Montpellier cedex 5, France.
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14
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Szewczuk-Karpisz K, Wiśniewska M. Lysozyme as a flocculant-inducing agent improving the silica removal from aqueous solutions - A turbidimetric study. J Environ Manage 2018; 226:187-193. [PMID: 30119043 DOI: 10.1016/j.jenvman.2018.08.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 06/08/2023]
Abstract
In this paper, the lysozyme (LSZ) adsorption impact on the silica suspension stability was established. In other words, the stabilization/destabilization mechanism of the SiO2/LSZ system was explained based on the adsorption, electrokinetic and stability measurement results. Lysozyme adsorbs on the silica surface in the whole pH range. This process contributes to the changes in silica surface charge and zeta potential values. The lysozyme addition influences the system stability too. At pH 7.6 and 9, a large decrease in the silica suspension stability was found. It is connected with the neutralization of solid negative charge by the positively charged macromolecules. As a result, large aggregates can be formed, which is highly desirable in the silica removal procedure.
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Affiliation(s)
| | - Małgorzata Wiśniewska
- Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
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15
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Dargó G, Boros K, Péter L, Malanga M, Sohajda T, Szente L, Balogh GT. Novel medium-throughput technique for investigating drug-cyclodextrin complexation by pH-metric titration using the partition coefficient method. Int J Pharm 2018; 542:100-7. [PMID: 29530562 DOI: 10.1016/j.ijpharm.2018.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study was aimed to develop a medium-throughput screening technique for investigation of cyclodextrin (CD)-active pharmaceutical ingredient (API) complexes. Dual-phase potentiometric lipophilicity measurement, as gold standard technique, was combined with the partition coefficient method (plotting the reciprocal of partition coefficients of APIs as a function of CD concentration). A general equation was derived for determination of stability constants of 1:1 CD-API complexes (K1:1,CD) based on solely the changes of partition coefficients (logPo/wN-logPappN), without measurement of the actual API concentrations. Experimentally determined logP value (-1.64) of 6-deoxy-6[(5/6)-fluoresceinylthioureido]-HPBCD (FITC-NH-HPBCD) was used to estimate the logP value (≈ -2.5 to -3) of (2-hydroxypropyl)-ß-cyclodextrin (HPBCD). The results suggested that the amount of HPBCD can be considered to be inconsequential in the octanol phase. The decrease of octanol volume due to the octanol-CD complexation was considered, thus a corrected octanol-water phase ratio was also introduced. The K1:1,CD values obtained by this developed method showed a good accordance with the results from other orthogonal methods.
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16
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Tesmar A, Wyrzykowski D, Kruszyński R, Niska K, Inkielewicz-Stępniak I, Drzeżdżon J, Jacewicz D, Chmurzyński L. Characterization and cytotoxic effect of aqua-(2,2',2''-nitrilotriacetato)-oxo-vanadium salts on human osteosarcoma cells. Biometals 2017; 30:261-275. [PMID: 28204978 PMCID: PMC5352783 DOI: 10.1007/s10534-017-0001-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 02/08/2017] [Indexed: 12/23/2022]
Abstract
The use of protonated N-heterocyclic compound, i.e. 2,2'-bipyridinium cation, [bpyH+], enabled to obtain the new nitrilotriacetate oxidovanadium(IV) salt of the stoichiometry [bpyH][VO(nta)(H2O)]H2O. The X-ray measurements have revealed that the compound comprises the discrete mononuclear [VO(nta)(H2O)]- coordination ion that can be rarely found among other known compounds containing nitrilotriacetate oxidovanadium(IV) moieties. The antitumor activity of [bpyH][VO(nta)(H2O)]H2O and its phenanthroline analogue, [phenH][VO(nta)(H2O)](H2O)0.5, towards human osteosarcoma cell lines (MG-63 and HOS) has been assessed (the LDH and BrdU tests) and referred to cis-Pt(NH3)2Cl2 (used as a positive control). The compounds exert a stronger cytotoxic effect on MG-63 and HOS cells than in untransformed human osteoblast cell line. Thus, the [VO(nta)(H2O)]- containing coordination compounds can be considered as possible antitumor agents in the osteosarcoma model of bone-related cells in culture.
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Affiliation(s)
- Aleksandra Tesmar
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Dariusz Wyrzykowski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland.
| | - Rafał Kruszyński
- Institute of General and Ecological Chemistry, Technical University of Łódź, Żwirki 36, 90-924, Łódź, Poland
| | - Karolina Niska
- Department of Medical Chemistry, Medical University of Gdańsk, Dębinki 1, 80-211, Gdańsk, Poland
| | | | - Joanna Drzeżdżon
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Dagmara Jacewicz
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
| | - Lech Chmurzyński
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308, Gdańsk, Poland
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17
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Margita K, Voinov MA, Smirnov AI. Effect of Solution Ionic Strength on the pK a of the Nitroxide pH EPR Probe 2,2,3,4,5,5-Hexamethylimidazolidin-1-oxyl. Cell Biochem Biophys 2017; 75:185-193. [PMID: 28210984 DOI: 10.1007/s12013-017-0780-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
Abstract
Spin probe and spin labeling Electron Paramagnetic Resonance methods are indispensable research tools for solving a wide range of bioanalytical problems-from measuring microviscosity and polarity of phase-separated liquids to oxygen concentrations in tissues. One of the emerging uses of spin probes are the studies of proton transfer-related and surface electrostatic phenomena. The latter Electron Paramagnetic Resonance methods rely on molecular probes containing an additional functionality capable of reversible ionization (protonation, in particular) in the immediate proximity to an Electron Paramagnetic Resonance-active reporter group, such as (N-O•) for nitroxides. The consequent formation of protonated and nonprotonated nitroxide species with different magnetic parameters (A iso, g iso) could be readily distinguished by Electron Paramagnetic Resonance. Bioanalytical Electron Paramagnetic Resonance studies employing pH-sensitive paramagnetic probes typically involve determination of the equilibrium constant (pK a) between the protonated and nonprotonated forms of the nitroxide. However, any chemical equilibrium involving charged species, such as ionization of acids and bases, and so the reversible protonation of the nitroxide, is known to be affected by an ionic strength of the solution. Currently, only scarce data for the effect of the solution ionic strength on the experimental pK a's of the ionizable nitroxides can be found in the literature. Here we have carried out a series of Electron Paramagnetic Resonance titration experiments for aqueous solutions of 2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl (HMI) nitroxide known for one of the largest differences in the isotropic nitrogen hyperfine coupling constant A iso between the protonated and nonprotonated forms. Electrolyte concentration was varied over an exceptionally large range (i.e., from 0.05 to 5.0 M) to elucidate the effect of ionic strength on the ionization constant of this pH-sensitive Electron Paramagnetic Resonance probe and the data were compared to the Debye-Hückel limiting law. Effects of the ionic strength on the magnetic parameters of the ionizable nitroxides are also discussed.
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Affiliation(s)
- Kaleigh Margita
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, 27606, NC, USA
| | - Maxim A Voinov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, 27606, NC, USA
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, 27606, NC, USA.
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18
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Kim JM, Nguyen L, Barr MF, Morabito M, Stringer D, Fitton JH, Mowery KA. Quantitative determination of fucoidan using polyion-sensitive membrane electrodes. Anal Chim Acta 2015; 877:1-8. [PMID: 26002205 DOI: 10.1016/j.aca.2015.04.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 12/20/2022]
Abstract
The use of polyanion and polycation-sensitive membrane electrodes to detect five different preparations of fucoidan is described. Unlike linear polyanionic molecules previously measured with polymer membrane-based electrochemical sensors, fucoidans from marine brown algae are all highly branched, sulfated polysaccharides with varying charge densities and structures, depending on the species of seaweed, method of extraction used and extent of purification. When tridodecylmethylammonium (TDMA) was used as the ion-exchanger, a large, non-equilibrium EMF response was observed over a concentration range of 0.5-50 μg mL(-1) fucoidan. Fucoidan was also measured by titration with polycationic protamine, using a dinonylnaphthalene sulfonate (DNNS)-doped membrane electrode as the potentiometric endpoint detector. Potentiometric titration was used to determine the binding ratio between protamine and fucoidan at the neutralization endpoint for each fucoidan preparation. This binding ratio was then used to successfully determine the fucoidan content of commercially available nutritional supplements. Fucoidan was also measured in undiluted blood serum, demonstrating that this method may be applicable for measuring fucoidan for clinical applications.
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19
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Schönherr D, Wollatz U, Haznar-Garbacz D, Hanke U, Box KJ, Taylor R, Ruiz R, Beato S, Becker D, Weitschies W. Characterisation of selected active agents regarding pKa values, solubility concentrations and pH profiles by SiriusT3. Eur J Pharm Biopharm 2015; 92:155-70. [PMID: 25758123 DOI: 10.1016/j.ejpb.2015.02.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/18/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
The aim of this work was to determine pKa values and solubility properties of 34active agents using the SiriusT3 apparatus. The selected drug substances belong to the groups of ACE-inhibitors, β-blockers, antidiabetics and lipid lowering substances. Experimentally obtained pKa and intrinsic solubility values were compared to calculated values (program ACD/ChemSketch) and pKa values to published data as well. Solubility-pH profiles were generated to visualise the substance solubility over the gastrointestinal pH range. The relationship between the solubility characteristic of a substance, its bioavailability and categorisation according to the Biopharmaceutics Classification System (BCS) was examined as well. The results showed a good agreement between experimentally obtained, calculated and published pKa values. The measured and calculated intrinsic solubility values indicated several major deviations. All solubility-pH profiles showed the expected shape and appearance for acids, bases or zwitterionic substances. The obtained results for the pKa and solubility measurements of the examined active agents may help to predict their physicochemical behaviour in vivo, and to understand the bioavailability of the substances according to their BCS categorisation. The easy and reproducible determination of pKa and solubility values makes the SiriusT3 apparatus a useful tool in early stages of drug and formulation development.
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Affiliation(s)
- D Schönherr
- University of Greifswald, Center of Drug Absorption and Transport, Institute of Pharmacy, 17487 Greifswald, Germany
| | - U Wollatz
- University of Greifswald, Center of Drug Absorption and Transport, Institute of Pharmacy, 17487 Greifswald, Germany
| | - D Haznar-Garbacz
- University of Greifswald, Center of Drug Absorption and Transport, Institute of Pharmacy, 17487 Greifswald, Germany
| | - U Hanke
- University of Greifswald, Center of Drug Absorption and Transport, Institute of Pharmacy, 17487 Greifswald, Germany
| | - K J Box
- Sirius Analytical Ltd., Forest Row, East Sussex RH18 5DW, UK
| | - R Taylor
- Sirius Analytical Ltd., Forest Row, East Sussex RH18 5DW, UK
| | - R Ruiz
- Sirius Analytical Ltd., Forest Row, East Sussex RH18 5DW, UK
| | - S Beato
- Novartis Pharma AG, Technical Research & Development, 4056 Basel, Switzerland
| | - D Becker
- Vivo Drug Delivery GmbH, 8832 Wollerau, Switzerland
| | - W Weitschies
- University of Greifswald, Center of Drug Absorption and Transport, Institute of Pharmacy, 17487 Greifswald, Germany.
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20
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Wiśniewska M, Ostolska I, Szewczuk-Karpisz K, Chibowski S, Terpiłowski K, Gun’ko VM, Zarko VI. Investigation of the polyvinyl alcohol stabilization mechanism and adsorption properties on the surface of ternary mixed nanooxide AST 50 (Al 2O 3-SiO 2-TiO 2). J Nanopart Res 2015; 17:12. [PMID: 25620881 PMCID: PMC4300396 DOI: 10.1007/s11051-014-2831-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 12/16/2014] [Indexed: 05/25/2023]
Abstract
A new adsorbent consisting of fumed, mixed alumina, silica, and titania in various proportions (AST 50) was investigated. The studied material was prepared by chemical vapor deposition method. The diameter of AST 50 primary particles was equal to about 51 nm which denotes that it can be classified as a nanomaterial. In the presented paper, the adsorption properties of polyvinyl alcohol on the ternary oxide were investigated. The polymer macromolecules were characterized by two different molecular weights and degree of hydrolysis. The polymer adsorption reaches the maximum at pH 3 and decreases with the solution pH rise. The reduction of the adsorbed PVA macromolecules is related to the electrostatic repulsion forces occurring in the studied system. The AST 50 point of zero charge (pHpzc) obtained from the potentiometric titration is equal to 4.7. Due to the nonionic character of the analyzed macromolecular compound, the polymer attendance has an insignificant effect on the AST 50 surface charge density. In the case of the adsorbent particles zeta potential, the obtained dependencies are different in the absence and presence of PVA. The shift of the slipping plane and displacement of the counter-ions from Stern layer by the adsorbed polymer chains have the greatest effect on the ζ potential value. The stability measurements indicate that the AST 50 suspensions in the presence of the background electrolyte at pH 3 and 6 are unstable. In turn, in an alkaline medium the mixed oxide suspensions exhibit the highest durability, which is a result of a large number of the negative charges on the AST 50 surface. The addition of PVA 100 significantly improves the suspension stability at pH 3 and 6; at higher pH value, the polymer presence does not influence the system durability. It is related to the steric and electrosteric stabilization of the colloidal particles by the adsorbed polyvinyl alcohol macromolecules.
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Affiliation(s)
- Małgorzata Wiśniewska
- Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Iwona Ostolska
- Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Katarzyna Szewczuk-Karpisz
- Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Stanisław Chibowski
- Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Konrad Terpiłowski
- Department of Physical Chemistry – Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Vladimir Moiseevich Gun’ko
- Institute of Surface Chemistry, National Academy of Sciences in Ukraine, 17 General Naumov Street, Kiev, 03164 Ukraine
| | - Vladimir Iljich Zarko
- Institute of Surface Chemistry, National Academy of Sciences in Ukraine, 17 General Naumov Street, Kiev, 03164 Ukraine
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21
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Buyuktimkin T, Wurster DE. The influence of the adsorption of metoclopramide on the surface ionization of fumed silica. Int J Pharm 2014; 478:164-171. [PMID: 25448578 DOI: 10.1016/j.ijpharm.2014.11.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 09/22/2014] [Accepted: 11/12/2014] [Indexed: 11/28/2022]
Abstract
The effect of adsorbed metoclopramide on the surface ionization of fumed silica was studied using potentiometric titration. Adsorption isotherms of metoclopramide to unionized and negatively-charged silica surfaces were generated and compared to the titration data. The adsorption of metoclopramide caused the silica surface charge to become more negative with increasing pH that was independent of ionic strength which suggested that specific adsorbate-surface interactions were occurring. Adsorption studies showed that metoclopramide adsorbs to the unionized silica surface. Ionization caused drug adsorption to increase which was consistent with at least two distinct surface adsorption sites. The ratio of the additional amount of metoclopramide adsorbed to the surface ionized group density determined from the titration curves was approximately unity which showed conclusively that the negatively-charged silanols constitute one of the surface adsorption sites. Potentiometric titration has been shown to be a useful technique for determining the number and types of adsorption sites on the silica surface.
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Affiliation(s)
- Tuba Buyuktimkin
- College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA.
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22
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Szewczuk-Karpisz K, Wiśniewska M, Pac M, Choma A, Komaniecka I. Sinorhizobium meliloti 1021 Exopolysaccharide as a Flocculant Improving Chromium(III) Oxide Removal from Aqueous Solutions. Water Air Soil Pollut 2014; 225:2052. [PMID: 25132693 PMCID: PMC4127006 DOI: 10.1007/s11270-014-2052-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/25/2014] [Indexed: 05/30/2023]
Abstract
Chromium(III) oxide is an amphoteric, dark green solid. This most stable dye is widely used in construction and ceramic industries as well as in painting. In this study, the attempt is made to determine flocculating properties of exopolysaccharide (EPS) synthesized by the bacteria Sinorhizobium meliloti 1021, which would increase the efficiency of chromium(III) oxide removal from sewages and wastewaters. The conditions under which EPS is the most effective destabilizing component of chromium(III) oxide suspension have been determined too. In order to characterize the structure of electric double layer formed at the solid/supporting electrolyte (EPS) solution interface, electrokinetic potential measurements and potentiometric titration were performed. The EPS amount adsorbed on the chromium(III) oxide surface as a solution pH function was also measured. Moreover, the stability of Cr2O3 suspension in the absence and presence of S. meliloti 1021 EPS was estimated. The pooled analysis of all obtained results showed that EPS causes chromium(III) oxide suspension destabilization in the whole examined pH range. The largest change in the system stability before and after the polymer addition was observed at pH 9. It is probable that under these conditions bridging flocculation occurs in the examined system.
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Affiliation(s)
- Katarzyna Szewczuk-Karpisz
- Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Małgorzata Wiśniewska
- Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Małgorzata Pac
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland
| | - Adam Choma
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland
| | - Iwona Komaniecka
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland
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Daikopoulos C, Bourlinos AB, Georgiou Y, Deligiannakis Y, Zboril R, Karakassides MA. A functionalized phosphonate-rich organosilica layered hybrid material (PSLM) fabricated through a mild process for heavy metal uptake. J Hazard Mater 2014; 270:118-126. [PMID: 24565929 DOI: 10.1016/j.jhazmat.2014.01.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/14/2014] [Accepted: 01/27/2014] [Indexed: 06/03/2023]
Abstract
A phosphonate-rich organosilica layered hybrid material (PSLM) made of 3-(trihydroxysilyl)propyl methylphosphonate, monosodium salt, as the single silica source, has been obtained from its aqueous solution through a xerogel process and mild thermal aging. The method is simple, affording bulk quantities of powdered PSLM in a single-step. The hybrid is stable in water and possesses a high content of phosphonate groups fixed on the solid matrix. In addition, PSLM shows good thermal stability, which exceeds 300°C in air. The material was characterized using SEM, TEM, XRD, FT-IR and TGA techniques. Potentiometric titrations show that PSLM bears high-surface density of phosphonate groups (3 mmol g(-1)). As a result, the material displays high metal uptake capacity for heavy metal ions such as Cu(2+) (2.72mmolg(-1)), Pb(2+) (1.67 mmol g(-1)) and Cd(2+) (1.00 mmol g(-1)) at neutral pH values e.g. the pH of natural waters. Detailed theoretical modeling using a Surface Complexation Model combined with Electron Paramagnetic Resonance (EPR) spectroscopy shows that the surface distribution of surface bound Cu(2+) ions is rather homogeneous e.g. copper-binding phosphonate sites are arranged in average distances 5-8Å.
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Affiliation(s)
- Chris Daikopoulos
- Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110, Greece
| | - Athanasios B Bourlinos
- Institute of Materials Science, NCSR "Demokritos", Ag. Paraskevi Attikis, Athens 15310, Greece
| | - Yiannis Georgiou
- Laboratory of Physical Chemistry, Department of Environmental and Natural Resources Management, University of Patras, Seferi 2, Agrinio 30100, Greece
| | - Yiannis Deligiannakis
- Laboratory of Physical Chemistry, Department of Environmental and Natural Resources Management, University of Patras, Seferi 2, Agrinio 30100, Greece.
| | - Radek Zboril
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Department of Physical Chemistry and Experimental Physics, Palacky University, Olomouc 77146, Czech Republic
| | - Michael A Karakassides
- Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110, Greece
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Maki H, Tsujito M, Sakurai M, Yamada T, Nariai H, Mizuhata M. Stabilities of the Divalent Metal Ion Complexes of a Short-Chain Polyphosphate Anion and Its Imino Derivative. J SOLUTION CHEM 2013; 42:2104-18. [PMID: 24319300 DOI: 10.1007/s10953-013-0099-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 06/28/2013] [Indexed: 12/01/2022]
Abstract
Abstract The stability constants of ML-type complexes of the two linear triphosphate ligand anion analogues triphosphate (\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{10}^{5 - } $$\end{document}P3O105-) and diimidotriphosphate (\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{ 8} ( {\text{NH}})_{2}^{5 - } $$\end{document}P3O8(NH)25-) were investigated thermodynamically using potentiometric titrations according to Schwarzenbach’s procedure. The stability constants of the ML-type complexes of different divalent metal ions with \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{ 8} ( {\text{NH}})_{2}^{5 - } $$\end{document}P3O8(NH)25- are larger than those of the corresponding complexes with \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{10}^{5 - } $$\end{document}P3O105- because of the greater basicity of the imino group. The order of the stability constants for the ML-type complexes follows the Irving–Williams order, indicating that only non-bridging oxygen atoms are coordinated directly to the different metal ions in both ligands, and that the imino groups cannot participate in coordination to the metal ions. In the complexation reactions of the Ca2+, Sr2+, Ba2+–\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{10}^{5 - } $$\end{document}P3O105- and Cu2+, Zn2+, Ni2+–\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{ 8} ( {\text{NH}})_{2}^{5 - } $$\end{document}P3O8(NH)25- systems, each metal ion forms an enthalpically stable complex, and there was no suggestion of a conspicuous entropic effect based on the chelate effect. Monodentate complexes that are strongly coordinated with the ligands were therefore formed, whereas entropically stable bidentate complexes were formed in the complexation reactions of the Cu2+, Zn2+, Ni2+–\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{10}^{5 - } $$\end{document}P3O105- and Ca2+, Ba2+, Sr2+–\documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{ 3} {\text{O}}_{ 8} ( {\text{NH}})_{2}^{5 - } $$\end{document}P3O8(NH)25- systems. According to the HSAB concept, hard metal cations such as Ca2+, Ba2+ and Sr2+ should bind to the harder oxygen atoms rather than the softer nitrogen atoms of the imidopolyphosphate anions, preventing direct coordination to the imino nitrogen atom. Graphical Abstract ![]()
Electronic supplementary material The online version of this article (doi:10.1007/s10953-013-0099-2) contains supplementary material, which is available to authorized users.
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Zhang T, Liu JM, Huang XF, Xia B, Su CY, Luo GF, Xu YW, Wu YX, Mao ZW, Qiu RL. Chelant extraction of heavy metals from contaminated soils using new selective EDTA derivatives. J Hazard Mater 2013; 262:464-471. [PMID: 24076482 DOI: 10.1016/j.jhazmat.2013.08.069] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 07/30/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals.
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Affiliation(s)
- Tao Zhang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
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Gagrai MK, Das C, Golder AK. Reduction of Cr(VI) into Cr(III) by Spirulina dead biomass in aqueous solution: kinetic studies. Chemosphere 2013; 93:1366-1371. [PMID: 24053944 DOI: 10.1016/j.chemosphere.2013.08.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 06/02/2023]
Abstract
Microalga species are potential scavengers of heavy metals. The active functional groups of a number of biomaterials are capable to detoxify Cr(VI) to Cr(III). A 2nd order kinetic model was developed in terms of concentration of protonated acidic groups of Spirulina sp. biomass for the reduction of Cr(VI) into Cr(III). Cr(VI) reduction reaction grounded on the concentration of functional groups was validated over a broad range of pH, temperature and anionic strength. Lower pH favoured Cr(VI) reduction reaction and the experimental results well fitted to the kinetic model. The overall rate constant, kt, decreased logarithmically from 22.7 to 2.8 mM⁻¹ s⁻¹ with rise of pH from 0.5 to 6.0. Whereas, k(t) increased nearly by 23% with elevation temperature from 25 to 45 °C. Higher concentration (>0.235 mM) of background anions (Cl⁻, SO₄²⁻ and NO₃⁻) was resulted in decreases in k(t) values. The rate constant expression developed can be employed to quantify Cr(VI) reduction into Cr(III) using Spirulina biomass.
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Affiliation(s)
- Mahesh Kumar Gagrai
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781 039, India
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Maki H, Tsujito M, Yamada T. Intrinsic 31P NMR Chemical Shifts and the Basicities of Phosphate Groups in a Short-Chain Imino Polyphosphate. J SOLUTION CHEM 2013; 42:1063-74. [PMID: 23761944 DOI: 10.1007/s10953-013-0011-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 10/27/2012] [Indexed: 11/26/2022]
Abstract
Abstract The stepwise protonation constants of two linear triphosphate ligand anions, triphosphate, \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{3} {\text{O}}_{10} ^{5 - } $$\end{document}P3O105− and di-imidotriphosphate, \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{3} {\text{O}}_{8} \left( {\text{NH}} \right)_{2}^{5 - } $$\end{document}P3O8(NH)25−, were investigated by potentiometric titration, and the intrinsic chemical shifts of the stepwise protonated species of these anions were determined from the pH-dependence of the 31P NMR chemical shifts. All stepwise protonation constants of \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{3} {\text{O}}_{8} \left( {\text{NH}} \right)_{2}^{5 - } $$\end{document}P3O8(NH)25−were found to be larger than those of \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{P}}_{3} {\text{O}}_{10}^{5 - } $$\end{document}P3O105−, and the 31P NMR signals due to P3O8(NH)2 always appeared at a lower magnetic field compared to the signals due to P3O10. These results indicate higher basicity of the P3O8(NH)2 ligand, because it contains two imino groups in the ligand molecule. The 31P NMR signals for the end phosphate groups appear at a lower magnetic field than those for the middle phosphate groups, indicating that the basicity of the end phosphate group is higher than that of the middle phosphate group. It can be expected that the high basicity of the P3O8(NH)2 ligand brings about the formation of high stability complexes with various metal ions. Furthermore, the only 31P NMR signal due to the middle phosphate group of P3O8(NH)2 ligand molecule clearly showed a low-field shift in the range of pH < 2.5. The reason for this peculiar low-field shift should be the change of the localization of imino protons around the nitrogen atom in P3O8(NH)2. Graphical Abstract ![]()
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