Using magnetic core-shell nanoparticles coated with an ionic liquid dispersion assisted by effervescence powder for the micro-solid-phase extraction of four beta blockers from human plasma by ultra high performance liquid chromatography with mass spectrometry detection.

In this work, a novel, efficient, and green sorbent, SiO2 @Fe3 O4 has been created and functionalized with 1-butyl-3-methylimidazolium hexafluorophosphate as an ionic liquid. This sorbent was applied for microextraction of four beta blockers, propranolol, metoprolol, atenolol, and alprenolol with bupivacaine as internal standard from human plasma followed by liquid chromatography with mass spectrometric detection. A mixture of sodium bicarbonate and sodium dihydrogen phosphate was used as an extractant dispersive agent (effervescent power) to enhance the interaction between the magnetic sorbent and analytes. Main affecting parameters on microextraction and elution were optimized. Figures of merit for dispersive solid phase extraction with ionic liquid coated magnetic nanoparticles assisted by effervescent powder were calculated under the optimized conditions. The detection limits for propranolol, metoprolol, atenolol, and alprenolol were found at 0.33, 0.62, 0.03, and 0.44 ng/mL, respectively. For all analytes, good linearity was obtained. Intra- (n = 5) and interday (n = 10) precision were both under 6.3% while the preconcentration factors were obtained in the range between 15-18. The extraction efficiencies for each analyte ranged from 75 to 91%. The method was successfully applied for determination of trace amounts of the beta blockers in human plasma samples.

A New Fluorescence Sensor for Cerium (III) Ion Using Glycine Dithiocarbamate Capped Manganese Doped ZnS Quantum Dots.

A new fluorescence sensor for Ce(3+)ions is reported in this paper. This sensor is based on the fluorescence quenching of glycine dithiocarbamate (GDTC)-functionalized manganese doped ZnS quantum dots (QDs) in the presence of Ce(3+)ions. The synthesis of ultra-small GDTC-Mn:ZnS quantum dots (QDs) is based on the co-precipitation of nanoparticles in aqueous Solution. The nanoparticles are characterized with fluorescence spectroscopy, UV-vis absorption spectra, high-resolution transmission electron microscopy, X-ray power diffraction (XRD), and infrared spectroscopy. In the test carried out, it was found that the interaction between Ce(3+)ions and GDTC capped Mn:ZnS QDs quenches the original fluorescence of QDs according to the Stern-Volmer equation and the results show the existence of collisional quenching process. A linear relationship was observed between the extent of quenching and the concentration of Ce(3+)in the range of 2.0 × 10(-6) to 3.2 × 10(-5) mol.L(-1), with a detection limit of 2.29 × 10(-7) mol.L(-1). The relative standard deviation of 1.61% was obtained for five replicate measurements. The possible quenching mechanism was also examined by fluorescence and UV-vis absorption spectra. The interference of other cations was negligible on the quantitative determination of Ce(3+). This method proved to be simple, sensitive, low cost, and also reliable for practical applications.

Development of a novel MWCNTs-triazene-modified carbon paste electrode for potentiometric assessment of Hg(II) in the aquatic environments.

In this approach, a new chemically modified carbon paste electrode was assembled for potentiometric assay of mercury(II) ion in the aqueous environments. Hereby, MWCNTs were used in the carbon paste composition to meliorate the electrical conductivity and sensitivity of the carbon paste owing to its exceptional physicochemical characteristics. Likewise, participation of the BEPT as a super-selective ionophore in the carbon paste composition boosted significantly the selectivity of the modified electrode towards Hg(II) ions over a wide concentration range of 4.0 × 10(-9)-2.2 × 10(-3) mol L(-1) with a lower detection limit of 3.1 × 10(-9) mol L(-1). Besides, Nernstian slope of the proposed sensor was 28.9(± 0.4)mV/decade over a pH range of 3.0-5.2 with potentiometric short response time of 10s. In the interim, by storing in the dark and cool dry place during non-usage period, the electrode can be used for at least 30 days without any momentous divergence of the potentiometric response. Eventually, to judge about its practical efficiency, the arranged sensor was utilized successfully as an indicator electrode for potentiometric titration of mercury(II) with standard solution of EDTA. As well, the quantitative analysis of mercury(II) ions in some aqueous samples with sensible accuracy and precision was satisfactorily performed.

Dichloridodi-µ(2)-hydroxido-di-µ(3)-oxido-octa-phenyl-tetra-tin(IV) dimethyl sulfoxide disolvate.

In the centrosymmetric tetra-nuclear title mol-ecule, [Sn(4)(C(6)H(5))(8)Cl(2)O(2)(OH)(2)]·2C(2)H(6)OS, the two independent tin(IV) atoms show distorted trigonal-bipyramidal SnC(2)O(3) and SnC(2)O(2)Cl coordination geometries. The four tin(IV) atoms are bridged by the hydroxo and oxo ligands, forming a ladder-like array of three edge-connected Sn(2)O(2) squares. The solvent mol-ecules are linked to the tetra-nuclear mol-ecule via O-H⋯O hydrogen bonds.

1-(3,5-Dichloro-phen-yl)-3-(2-meth-oxy-phen-yl)triaz-1-ene.

The title mol-ecule, C(13)H(11)Cl(2)N(3)O, is almost planar and adopts a trans conformation with respect to the -N=N- bond; the dihedral angle between the rings is 3.47 (2)°. The N-N bond lengths indicate the presence of single- and double-bond characters and hence the -N=N-NH- moiety. In the crystal, inversion dimers linked by pairs of N-H⋯Cl hydrogen bonds occur, and C-H⋯π and π-π stacking interactions are also observed.

N-(2-Eth-oxy-phen-yl)formamide.

The title compound, C(9)H(11)NO(2), was obtained as an unexpected product in an attempt to synthesize a triazene ligand. The title mol-ecule is almost planar, with the formamide and eth-oxy groups oriented at 2.7 (3) and 12.9 (2)°, respectively, with respect to the mean plane of the benzene ring. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O hydrogen bonds, forming a chain along the a axis. Weak C-H⋯π inter-actions with an H⋯π distance of 2.78 Šreinforce the crystal packing, resulting in a three-dimensional network.

4-[(4-Bromo-phen-yl)diazen-yl]-2-eth-oxy-aniline.

The title compound, C(14)H(14)BrN(3)O, exhibits a trans geometry about the -N=N- double bond. The dihedral angle between the benzene rings is 24.01 (5)°. An intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, inter-molecular N-H⋯N hydrogen bonds between the amine groups lead to the formation of a C(8) polymeric chain along [101].

4-[(4-Chloro-phen-yl)diazen-yl]-3-meth-oxy-aniline.

The title compound, C(13)H(12)ClN(3)O, exhibits a trans geometry about the N=N double bond in the solid state. The dihedral angle between the rings is 22.20 (8)°. Inter-molecular N-H⋯O hydrogen bonds between the amine and meth-oxy groups lead to the formation of a chain-like polymer along the c axis with a C(6) graph set. There is also weak non-classical C-H⋯N hydrogen bonds involving an aromatic C-H group and a diazenyl N atom, which connect the chains into a two-dimensional framework.

Solid phase extraction of ultra traces mercury (II) using octadecyl silica membrane disks modified by 1,3-bis(2-ethoxyphenyl)triazene (EPT) ligand and determination by cold vapor atomic absorption spectrometry.

A facile and highly efficient method was developed for the preconcentration of the ultra trace amounts of mercury (II) ions. Octadecyl silica membrane disk was modified by the recently synthesized triazene ligand, 1,3-bis(2-ethoxyphenyl)triazene (EPT), and cold vapor atomic absorption spectrometry was used to determine the resultant preconcentrated Hg(II) ions. Solution studies with EPT and a series of metal ions were done in advance, and the results showed a strong affinity of EPT to the mercury ions. To perform solid phase extraction, various parameters such as pH of the sample, flow rates and the amount of the ligand were optimized. A linear calibration curve was obtained in the range of 0.02-1.90 µg L(-1) with r(2) = 0.9990 (n = 8), and the limit of detection (LOD) based on three times the standard deviation of the blank was 10.6 ng L(-1). The relative standard deviation (RSD) for the determination of 0.1 µg L(-1) Hg(II) found to be 2.9% while a RSD value of 1.1% was obtained for the determination of 1.0 µg L(-1) Hg(II) (n = 8). The preconcentration and improvement factors were 380 and 74, respectively. The newly developed method was successfully applied to the determination of mercury ions in real water samples.

An investigation on the new operational parameter effective in Cr(VI) removal efficiency: a study on electrocoagulation by alternating pulse current.

The performance of an electrocoagulation (EC) process with aluminum/iron electrodes for removal of chromium on laboratory scale was studied. The effect of operational parameters such as initial pH, current density (CD), reaction time, initial concentrations (50, 100, 500, 1000 mg/L), solution conductivity, electrical energy consumption (EEC) and type of circuit were studied in an attempt to reach higher Cr(VI) removal efficiency. Alternating pulse current (APC) was used to prevent the passivity or polarization of electrodes. Important operating parameters were optimized to access higher (99%) Cr(VI) removal efficiency as follows: EEC range: 4-58 kW h/m(3) wastewater, CD: 56-222 A/m(2), operating time: 20-110 min, pH 3-9 (pH(optimum) 5), voltage: 15-25 V. NaCl, KCl, PAC (poly aluminum chloride), NaNO(3) were used as supporting electrolytes. NaCl as well as KCl handled the EC with the best performance in every aspect; however, PAC and NaNO(3) did not have the same results (Applied conductivity is better than literature). The results of this work are comparable with those of recent studies. Equal removal efficiency was obtained in "direct current" (DC) and (APC); however, when "APC" was used, water recovery (0.92 m(3)/m(3) wastewater) was significant and the turbidity was 1 NTU. "APC" amazed our experimental team.

Multi-walled carbon nanotubes-ionic liquid-carbon paste electrode as a super selectivity sensor: application to potentiometric monitoring of mercury ion(II).

In this article a super selectivity potentiometric methodology, using an ion-selective electrode, for determination of mercury ion(II) in aqueous solution was investigated. For modification of the electrode a room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIM·BF(4)), was applied as a super conductive binder, and Multi-walled carbon nanotubes (MWCNTs) was used in the composition of the carbon paste to improve conductivity and transduction of chemical signal to electrical signal. Moreover, incorporation of 1-(2-ethoxyphenyl)-3-(3-nitrophenyl)triazene (ENTZ) as an ionophore to this composition caused to significantly enhanced selectivity toward Hg(II) ions over a wide concentration range of 1.0×10(-4) to 5.0×10(-9) M with a lower detection limit of 2.5×10(-9) M (0.5 ppb) and a Nernstian slope of 29.3±(0.2) mV decade(-1) of Hg(II) activity. The electrode has a short response time (∼5s) and can be used for at least 55 days without any considerable divergence in potentials, and the working pH range was 2.0-4.3. Finally, the proposed electrode was successfully used as an indicator for potentiometric determination of Hg(II) in dental amalgam and water samples.

Chlorido[1-(2-eth-oxy-phen-yl)3-(4-nitro-phen-yl)triazenido]mercury(II).

In the title compound, [Hg(C(14)H(13)N(4)O(3))Cl], the Hg(II) atom is four-coordinated by one O atom and two N atoms from a tridentate 1-(2-eth-oxy-phen-yl)-3-(4-nitro-phen-yl)triazenide ligand and one terminal chloride ion in a distorted square-planar geometry. In the crystal structure, the mononuclear complexes are linked into pairs through C-H⋯O and C-H⋯Cl hydrogen bonds as well as π-π and C-H⋯π stacking inter-actions. In addition, weak Hg-µ(6)-arene π-inter-actions [mean distance of 3.667 (2) Å] are present between these dimers. The π-π stacking inter-actions are between aromatic rings with a centroid-centroid distance of 3.884 (2) Å. Moreover, edge-to-face inter-actions are present between eth-oxy CH groups and aromatic rings with H⋯π distances of 2.81 Å.

Bis[1-(2-eth-oxy-phen-yl)-3-(4-nitro-phen-yl)triazenido]mercury(II).

In the title compound, [Hg(C(14)H(13)N(4)O(3))(2)], the central Hg atom (site symmetry 2) is six-coordinated by two tridentate 1-(2-eth-oxy-phen-yl)-3-(4-nitro-phen-yl)triazenide ligands through two N and one O atoms. The mononuclear complex mol-ecules are connected into two parallel chains by inter-molecular C-H⋯O hydrogen-bonding inter-actions. These chains are connected to each other by face-to-edge C-H⋯π inter-actions between the CH of the ethoxy groups and the aromatic rings, resulting in a two-dimensional architecture in the ac plane.

Solid phase extraction of ultra traces silver(I) using octadecyl silica membrane disks modified by 1,3-bis(2-cyanobenzene) triazene (CBT) ligand prior to determination by flame atomic absorption.

A simple, reliable and rapid method for preconcentration and determination of the ultra trace amount of silver using octadecyl silica membrane disk modified by a recently synthesized triazene ligand, 1,3-bis(2-cyanobenzene)triazene (CBT), and flame atomic absorption spectrometry is presented. Various parameters including pH of aqueous solution, flow rates, the amount of ligand and the type of stripping solvents were optimized. The breakthrough volume was greater than 1800 ml with an enrichment factor of more than 360 and 6.0 ng l(-1) detection limit. The capacity of the membrane disks modified by 5mg of the ligand was found to be 1070 microg of silver. The effects of various cationic interferences on the percent recovery of silver ion were studied. The method was successfully applied to the determination of silver ion in different samples, especially determination of ultra trace amount of silver in the presence of large amount of lead.

Novel platinum(II) selective membrane electrode based on 1,3-bis(2-cyanobenzene)triazene.

A plasticized poly (vinyl chloride) membrane electrode based on 1,3-bis(2-cyanobenzene)triazene (CBT) for highly selective determination of platinum(II) (in PtCl(4)(2-) form) is developed. The electrode showed a good Nernstian response (29.8+/-0.3 mV decade(-1)) over a wide concentration range (1.0 x 10(-6) to 1.0 x 10(-2)mol L(-1)). The limit of detection was 5.0 x 10(-7)mol L(-1). The electrode has a response time of about 40s, and it can be used for at least 1 month without observing any considerable deviation from Nernstian response. The proposed electrode revealed an excellent selectivity toward platinum(II) ion over a wide variety of alkali, alkaline earth, transition, and heavy metal ions, and it could be used in the pH range of 3.2-5.1. The practical utility of the electrode has been demonstrated by its use in determination of platinum ion in, alloy, tap, mineral and river water samples.

Bis[1,3-bis-(2-cyano-phen-yl)triazenido]mercury(II).

In the title compound, [Hg(C(14)H(8)N(5))(2)], the central atom is four-coordinated by two bidentate 1,3-bis-(2-cyano-phen-yl)triazenide ligands in a distorted square-planar geometry. The asymmteric unit is composed of one ligand molecule and one Hg(II) ion, which is disordered over two sites, one lying on an inversion center and the other on a general position with site-occupancy factors of 0.2378 (7) and 0.3811 (7), respectively. The monomeric mol-ecules of the complex are linked into pairs through non-classical C-H⋯N hydrogen bonds. The resulting dimeric units are assembled by translation along the crystallographic c axis into chains linked through secondary π-π inter-actions [centroid-centroid distances = 3.685 (2) and 3.574 (2) Å], as well as C-H⋯π stacking inter-actions, resulting in a two-dimensional architecture.

[1,3-Bis(2-ethoxy-phen-yl)triazenido]bromidomercury(II).

To the central atom of the title compound, [HgBr(C(16)H(18)N(3)O(2))], is attached one bromide ion and a 1,3-bis-(2-ethoxy-phen-yl)triazenide ligand through one O and two N atoms, forming a distorted square-planar geometry around the Hg(II) atom. The mononuclear complexes are linked into centrosymmetric dimers by non-classical inter-molecular C-H⋯N hydrogen bonds and by weak Hg-η(3)-arene π-inter-actions [mean distance = 3.434 (3) Å]. The resulting dimeric units are assembled into zigzag chains by translation along the crystallographic c axis through secondary C-H⋯π edge-to-face benzene ring inter-actions.

1,3-Bis(2-ethoxy-phen-yl)triazene methanol 0.33-solvate.

There are three independent mol-ecules of 1,3-bis-(2-ethoxy-phen-yl)triazene and a mol-ecule of methanol in the asymmetric unit of the title compound, C(16)H(19)N(3)O(2)·0.33CH(3)OH. Two mol-ecules related by a non-crystallographic pseudo-twofold rotation axis are linked via distinct inter-molecular N-H⋯N hydrogen bonds, leading to the formation of a dimer with an R(2) (2)(8) graph set. The third mol-ecule is connected to the methanol mol-ecule by O-H⋯N and N-H⋯O hydrogen bonds. There are a number of weak C-H⋯π inter-actions, with H⋯π distances ranging from 2.74 to 2.89 Šbetween the C-H groups and the aromatic benzene rings.

[1,3-Bis(2-ethoxy-phen-yl)triazenido]chloridomercury(II).

In the title compound, [Hg(C(16)H(18)N(3)O(2))Cl], the Hg(II) atom is four-coordinated in a tetra-hedral geometry by two N atoms from the 1,3-chelating and one O atom of a 1,3-bis-(2-ethoxy-phen-yl)triazenido ligand and one terminal chloride ion. The dihedral angle between the aromatic rings is 1.72 (14)°. In the crystal C-H⋯π stacking inter-actions occur.

trans-Bis[1,3-bis-(2-methoxy-phen-yl)triazenido]dimethano-lcadmium(II).

In the title compound, [Cd(C(14)H(14)N(3)O(2))(2)(CH(3)OH)(2)], each cadmium(II) center is six-coordinated by an N atom and an O atom of two 1,3-bis-(2-methoxy-phen-yl)triazene ligands and by the O atoms of two methanol mol-ecules. The distorted octa-hedral coordination geometry of the Cd atom has two N and two O atoms in the equatorial plane, and two O atoms in axial positions. The complex is stabilized by intra-molecular O-H⋯O and O-H⋯N hydrogen bonds. In the crystal structure the complexes are linked into chains via inter-molecular C-H⋯π stacking inter-actions. One of the methanol C atoms is disordered with ouccupancies of 0.7:0.3.