Novel lanthanum(III) membrane sensor based on a new N-S Schiff’s base

Thorium is surprisingly abundant in the Earth's crust, being almost as abundant as lead and three times more abundant than uranium. It is found in small amounts in most rocks and soils. Granitile contains up to 80 ppm of thorium. Thorium occurs naturally as the minerals thorite, uranothorite, and thorianite. It is a major component of monazite and it is present in significant amounts in the minerals zircon, titanite, gadolinite and betafite. The amounts of thorium in the environment may be incidentally increased due to accidental releases of thorium processing plants. Uncontrolled large amounts of thorium may be found near hazardous waste sites where thorium has not been disposed of according to the proper procedures. People living near these sites may get exposed to more thorium as they breathe in windblown dust and because it ends up in food that is grown near the site.Since thorium has the ability to change genetic arrangements, it may increase the chances of developing the lung diseases and pancreas cancer. 1 Therefore, more efforts are required to develop ion-selective electrodes of commercial standards for heavy metal ions that are toxic beyond a certain concentration level. 2A literature survey showed that only three-potentiometric electrodes are available for detecting and/or measuring and monitoring thorium in environmental media. 3-5The present work describes the working of a sensor involving a dithio-tetraaza macrocyclic compound, namely 2,3,7,8-tetraphenyl-1,4,6,9-tetraaza-cyclodeca-5,10-dithion-1,3,6,8-tetraene (TPTACDTT) as ionophore, 3% sodium tetraphenyl borate (NaTPB) as an additive and 62% nitrobenzene (NB) as a plasticizing solvent mediator for thorium(IV) ions. This novel Th 4+ -selective electrode not only possesses the advantages of the simplicity of the design in membrane preparation but also has a fast response time, good linear range and detection limit and high selectivity over a variety of various metal ions; in many respects the values are better than those reported in the literature. 3-5 Experimental Reagents and chemicalsReagent grade benzyl acetate (BA), nitrobenzene (NB), sodium tetraphenyl borate (NaTPB), tetrahydrofuran (THF) and high relative molecular weight PVC (all from Merck and Aldrich) were used as received. The nitrate and chloride salts of all cations used (all from Merck and Aldrich) were of the highest purity available and were used without any further purification except for vacuum drying over P2O5. Doubly distilled deionized water was used throughout. Synthesis of ionophore TPTACDTTTo a hot ethanolic solution (50 ml) of benzil (0.093 M, 6.3 g) acidified with 0.5 ml conc. HCl, a hot ethanolic solution (50 ml) of thiourea (0.03 M >2.28 g approx.) was added drop-wise with stirring. Then the reaction mixture was refluxed at 60˚C for more than 12 h. The reaction mixture was kept in a cool place for 24 h and finally a light greenish yellow, bright crystalline compound was obtained. This was filtered on a buchner funnel using a suction pump, followed by washing with EtOH a...

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“…[10][11][12][13][14] Thus, the membrane sensor with composition of 30% PVC; 62% NB; 3% NaTPB, and 5% TPTACDTT exhibits the best performance.…”

Section: Potential Response Of the Th(iv) Sensor Based On Tptacdttmentioning

confidence: 98%

A Highly Selective and Sensitive Thorium(IV) PVC Membrane Electrode Based on a Dithio-tetraaza Macrocyclic Compound

2007

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“…Double distilled water was used for the preparation of metal salt solutions of different concentrations by diluting stock solutions (0.1 M). We have developed a highly La(III)-selective PVC membrane electrode based on a hexaaza macrocycle,8,3,4:10,11,3,5,9,11,5,8,11,13,hexaeneN6] (I) as membrane carrier, dibutylbutyl phosphonate (DBBP) as solvent mediator and sodium tetraphenylborate (NaTPB) as lipophilic additive. The best performance was given by the membrane of macrocycle I having a composition 10:260:5:120 (I:DBBP:NaTPB:PVC).…”

Section: Reagentsmentioning

confidence: 99%

“…[1][2][3][4] In spite of successful progress in the design of highly selective ionophores for various metal ions, there are only a limited number of reports on the development of highly selective ionophores for lanthanum. [5][6][7][8][9][10][11][12][13][14][15][16][17] Macrocyclic complexes of lanthanides [18][19][20] have generated a growing interest because of their potential applications in biology, 21 material science and in chemical processes. 22 Owing to the hard character of lanthanide(III) ions, the investigations of their coordination properties has focused on various aza and aza-oxa ligands.…”

Section: Introductionmentioning

confidence: 99%

A Selective Membrane Electrode for Lanthanum(III) Ion Based on a Hexaaza Macrocycle Derivative as Ionophore

et al. 2006

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The design and function of synthesized macrocyclic carriers for cationic selective membrane sensors are usually based on such diverse parameters as the structure and cavity size of ion carrier, the stability and selectivity of its metal ion complexes, its solubility and its ability to extract the target ion into membrane phase. In recent decades, many intensive studies on the design and synthesis of highly selective ionophores as sensory molecules for ion-selective electrodes have been reported. [1][2][3][4] In spite of successful progress in the design of highly selective ionophores for various metal ions, there are only a limited number of reports on the development of highly selective ionophores for lanthanum. [5][6][7][8][9][10][11][12][13][14][15][16][17] Macrocyclic complexes of lanthanides [18][19][20] have generated a growing interest because of their potential applications in biology, 21 material science and in chemical processes. 22 Owing to the hard character of lanthanide(III) ions, the investigations of their coordination properties has focused on various aza and aza-oxa ligands.23 Lanthanide(III) chelates find extensive use in NMR biomedical applications, 24 as ion exchanger materials. 25 Studies on these complexes have produced technological development and industrial applications. 26Lanthanides are widely distributed in low concentration throughout the earth's crust. 27 The vapors or dust of these elements are very toxic when inhaled. They tend to remain in human lungs, liver, spleen and kidneys. 28 We have synthesized new macrocyclic ligands that have been used as neutral carriers in the construction of ISEs for various metal ions. [29][30][31] A survey of the literature shows that incorporation of pyridine rings in the macrocyclic framework increases the stereochemical rigidity and binding ability towards the lanthanide(III) cations, a property often associated with an increase in the thermodynamic stability of the complexes. 32 neutron activation analysis, 37 and X-ray fluorescence spectrometry 38 have been reported for the determination of lanthanum.However, they are time consuming, involving multiple sample manipulations, they are too expensive for many analytical laboratories and they require large infrastructure back up. A simple, cheaper and more convenient method with fast response is required for analysis of large number of environmental and other samples. The analysis by ion-selective sensors provides such procedures. Experimental ReagentsAll the reagents were of analytical grade. Lanthanum(III) nitrate (Merck) was used as lanthanum salt for the studies of membrane sensor. 1-Phenyl-1,3-butanedione was prepared as reported in the literature, 39 while 2,6-diaminopyridine was procured from Sigma-Aldrich. MeOH was refluxed and distilled over lime before use. Reagent grade sodium tetraphenylborate (NaTPB), dibutylbutyl phosphonate (DBBP), dioctylphthalate (DOP), benzyl acetate (BA), o-nitrophenyloctyl ether (o-NPOE), tetrahydrofuran (THF) and high molecular weight PVC were purchased from Me...

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“…[30][31][32][33][34][35][36][37][38][39][40] We investigated the influences of membrane compositions on the potential responses of the Cu(II) sensor. The results are summarized in Table 2.…”

Section: Effect Of Membrane Composition On the Potential Response Of mentioning

confidence: 99%

Synthesis of 4-amino-6-methyl-1,2,4-triazin-5-one-3-thione and its application in construction of a highly copper(II) ion-selective electrochemical sensor

Zamani¹,

Rajabzadeh²,

Firouz³

et al. 2005

J. Braz. Chem. Soc.

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Um sensor altamente seletivo para Cu(II) usando 4-amino-6-metil-1,2,4-triazina-5-ona-3-tiona (AMTOT) como material seletivo, foi desenvolvido utilizando uma membrana de PVC. O eletrodo exibe um intervalo dinâmico linear entre 1,0×10 -1 e 1,0×10 -6 mol L -1 , com resposta Nernsteniana de 29,3 ± 0,6 mV por década e um limite de detecção de 6,2×10 -7 mol L -1 . A resposta do eletrodo é independente do pH, no intervalo entre 2,5 e 7,0. O sensor possui a vantagem de apresentar um tempo de condicionamento pequeno, uma rápida velocidade de resposta (< 20 s) e especialmente, uma boa seletividade frente a metais pesados e de transição, e a alguns cátions mono, di e trivalentes. O eletrodo pode ser usado por até 9 semanas sem consideráveis divergências de potencial. O eletrodo proposto foi aplicado com sucesso na determinação de cobre em águas de descarte, oriundas de plantas eletroquímicas de cobre e como eletrodo indicador na titulação potenciométrica de íons Ca(II) com EDTA.A highly Cu(II) ion-selective PVC membrane sensor based on 4-Amino-6-methyl-1,2,4-triazin-5-one-3-thione (AMTOT) as an excellent sensing material was developed. The electrode exhibits a linear dynamic range between 1.0×10 -1 and 1.0×10 -6 mol L -1 , with a near Nernstian slope of 29.3 ± 0.6 mV per decade and a detection limit of 6.2×10 -7 mol L -1 . The sensor response is independent of the pH of the solution in the pH range of 2.5 -7.0. The sensor possesses the advantages of short conditioning time, fast response time (<20 s), and especially, very good selectivity towards transition and heavy metal, and some mono, di and trivalent cations. The electrode can be used for at least 9 weeks without any considerable divergence in the potentials. The proposed electrode was successfully applied to the determination of copper in wastewater of copper electroplating samples and as an indicator electrode in potentiometric titration of Ca(II) ions with EDTA.Keywords: potentiometry, copper sensor, PVC membrane, 4-amino-6-methyl-1,2,4-triazin-5-one-3-thione IntroductionDuring the last decade, there has been a renewed resurgence in developing potentiometric membrane electrodes as devices for rapid, accurate, low cost and non destructive analysis of different samples with small volume samples.Due to the necessary need for selective copper measurements in many copmplex biological systems, 1,2 geochemical, 3 environmental, medicinal and industrial samples, 4 the search for new selective and sensitive PVCmembrane electrodes for its quick measurement is still a challenging goal. We have recently reported a number of highly selective and sensitive membrane sensors for various metal ions. [23][24][25] In this paper, we wish to introduce a highly copper(II)-selective sensor based on 4-Amino-6-methyl-1,2,4-triazin-5-one-3-thione (AMTOT), as a novel neutral ionophore for monitoring of copper in industrial samples (Figure 1). Experimental ReagentsReagent grade 2-nitrophenyl octyl ether (NPOE), dibutyl phthalate (DBP), benzyl acetate (BA), nitrobenzene (NB), sodium tetraphen...

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Novel lanthanum(III) membrane sensor based on a new N-S Schiff’s base

Cited by 81 publications

References 14 publications

A Highly Selective and Sensitive Thorium(IV) PVC Membrane Electrode Based on a Dithio-tetraaza Macrocyclic Compound

A Highly Selective and Sensitive Thorium(IV) PVC Membrane Electrode Based on a Dithio-tetraaza Macrocyclic Compound

A Selective Membrane Electrode for Lanthanum(III) Ion Based on a Hexaaza Macrocycle Derivative as Ionophore

Synthesis of 4-amino-6-methyl-1,2,4-triazin-5-one-3-thione and its application in construction of a highly copper(II) ion-selective electrochemical sensor

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