Colorimetric determination of copper(II) ions by filtration on sol-gel membrane doped with diphenylcarbazide

A simple and sensitive colorimetric method for the determination of trace copper(II) ions in aqueous solution has been developed using diphenylcarbazide (DPC) immobilized sol-gel matrices. To enhance the odds of chelating interactions between copper(II) ions and DPC, a peristaltic pump was utilized to drive copper(II) ions solution pass through the cellulose acetate/nitrate membrane, which was coated with DPC immobilized sol-gel matrices. The membrane was sandwiched in a home-made flow cell. The porous silica matrix serves as a preconcentrator, and enriches the trace copper(II) ions. Meanwhile, the filtration increases the chelating interaction probability between copper(II) ions and DPC, thereby improves the sensitivity significantly. After the formation of purple complex compound, the color changes of the DPC immobilized sol-gel membrane were recorded using a flatbed scanner. The images were digitized, and the red (R), green (G), and blue (B) values were investigated. The colorimetric method provides a rapid and reliable determination of trace copper(II) ions with a detection limit as low as 0.16 μM and a kinetic range up to 1.6 μM in neutral medium. Moreover, the method shows good selectivity, and the color changes of the DPC immobilized sol-gel membranes are remarkable for the copper(II) ions detection even in the presence of other metal ions.     

Dye removal,antibacterial properties,and morphological behavior of hydroxyapatite doped with Pd ions

Hydroxyapatite (HAP) containing different contents of palladium (Pd) ions were synthesized using the co-precipitation method. The structural and morphological properties of the as-synthesized compositions were investigated using XRD and FESEM. The c/a increased from 0.728 to 0.733 with the lowest and highest contributions of Pd(II), respectively. Furthermore, the morphological features were investigated using FESEM. It was illustrated that Pd-HAP was formed as agglomerated as rod shapes with dimensions in the range of 63.4–110.3 nm for no Pd additions, and the size was reduced reaching 43.4–70.5 nm for the highest Pd contribution. Besides, the maximum height of the roughness (R_t) grew from 183.6 up to 236.5 nm for the lowest and highest Pd(II). Besides, the obtained specific surface area was around 28.3, 42.0, and 63.4 m²/g for 0.0Pd-HAP, 0.6Pd-HAP, and 1.0Pd-HAP, respectively. The antibacterial activity was examined against both Escherichia coli (E-coli) and Staphylococcus aureus (S. aureus), and it obvious that the activity was enhanced upon Pd content. The inhibition zone was increased from no sensitivity reaching 4.3 ± 0.9 and 4.5 ± 0.8 mm for no Pd and the highest one, respectively. The removal efficiency of dyes was examined for methylene blue (MB) and it was shown that after 120 min of irradiation, the removal efficiency reached around 86.4% for the highest contribution of Pd. The pseudo-first-order constant (K_app) increased from 0.0032 to 0.0179 min⁻¹. The recyclability of Pd-HAP denoted that removal efficiency decreased to 5.65, 8.14, 6.24, 8.76, and 10.2% for different contents of Pd(II) after 6 cycles.     

金属离子Cu~(2+)，Co~(2+)，Ni~(2+)的微芯片电泳分离及化学发光检测

根据流动注射－化学发光的通用实验装置图，设计并通过标准光刻技术，湿化 学刻蚀及热键合技术制作了玻璃微芯片。在该芯片上将毛细管电泳分离与化学发光 检测相联用，鲁米诺和H_2O_2化学发光反应溶液通过实验室自制的微流泵输送。对 所用电压，缓冲溶液和发光试剂流速等实验条件进行了优化。在所选的最佳条件下 ，成功地实现了金属离子Cu~(2+)，Co~(2+)，Ni~(2+)的电泳分离－化学发光检测， 过渡金属离子。     

Entrapment and release of sodium polystyrene sulfonate (SPS) from calcium alginate gel beads

The release of sodium polystyrene sulfonate (SPS) from calcium alginate hydrogel beads has been studied. It has been shown that the structure of the cross-linked calcium alginate network is of primary importance in the retention and/or release of the SPS. This has been evidenced by studying the influence of Ca²⁺ concentration, molar masses (M_n) and the ratio of mannuronic acid/guluronic acid components. A minimum in the SPS release is observed in relation with the organization of the network structure. Conditions inducing the organization of a strong gel (e.g. high Ca²⁺ concentration for example) are not always related to a low release. A good control of release is found when a compromise between a well-structured hydrogel and sterical consideration of SPS is reached.     

Hydrogels of sodium alginate based copolymers grafted with sodium-2-acrylamido-2-methyl-1-propane sulfonate and methacrylic acid for controlled drug delivery applications

Novel sodium alginate based hydrogels were prepared by grafting the binary mixture of methacrylic acid and sodium-2-acrylamido-2-methyl-1-propane sulfonate on to sodium alginate (SA) with N,N'-methylenebisacrylamide (MBA) and ammonium persulfate (APS) as crosslinker and initiator respectively. The resultant SA-g-poly(AMPSNa-co-MAA) hydrogels were characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). The results indicated that an increase in the amount of sodium-2-acrylamido-2-methyl-1-propane sulfonate, swelling capacity was found to increase. The effects of temperature, pH and inorganic salt on the swelling behavior of the hydrogels were investigated. The pH reversibility behavior at pH levels of 1.0 and 9.0 indicated great potential of this hydrogel as a candidate system for controlled drug delivery.     

Synthesis and evaluation of the anticancer activity of the water-dispersible complexes of 4-acylaminoisoxazole derivative with biocompatible nanocontainers based on Ca2+ (Mg2+) cross-linked alginate

Water-dispersible complexes of 4-methyl-N-[5-methyl-3-(3,4,5-trimethoxyphenyl)isoxazol-4-yl]benzamide possessing anticancer activity were prepared by its immobilization with biocompatible polymer nanocontainers based on sodium alginate cross-linked with Ca²⁺ and Mg²⁺ ions. It was found that this isoxazole derivative retains its structure during immobilization. Colloidal stable nanocontainers filled with this compound exhibit toxicity toward the colon carcinoma (HCT116) tumor cell line.     

Modified cotton fabrics with poly (3-(furan-2-carboamido) propionic acid) and poly (3-(furan-2-carboamido) propionic acid)/gelatin hydrogel for UV protection,antibacterial and electrical properties

This research aimed to prepare smart cotton fabrics with multi functions for antibacterial activity, UV protection and electrical conductivity via in situ coating with conductive polymer and conductive hydrogel. Therefore, 3-(furan-2-carboamido) propionic acid was synthesized followed by polymerization using ceric ammonium nitrate. In addition, cotton fabrics coated with 3-(furan-2-carboamido) propionic acid via in situ polymerization and by the hydrogel that based on poly (3-(furan-2-carboamido) propionic acid) and gelatin which have been performed via in situ gelation process. The chemical structure and morphology of the 3-(furan-2-carboamido) propionic acid (monomer) and the synthesized polymer (PFu) were investigated by H¹NMR, IR, SEM, TGA and DSC. Where, the treated fabrics (PFu-T and PFu-G-T) are characterized by SEM, FTIR and contact angle. Furthermore, the AC electrical conductivity and dielectric properties of PFu, PFu-T, PFu-G-T and blank were investigated over the frequency range of 20 Hz–10 MHz at room temperature using impedance spectroscopy where the electric conductivity values are 1.74 × 10^-5, 7.5 × 10^-8, 4 × 10^-7, 8.24 × 10^-11 (S·cm)^-1, respectively. In addition, the anti-bacterial activity of PFu-T, PFu-G-T and blank was assessed versus gram-positive and gram-negative bacteria where, PFu-G-T shows activity against Escherichia coli and Staphylococcus aureus. Moreover, PFu-T, PFu-G-T showed high UV protection especially for PFu-G-T.     

柱后衍生离子色谱法同时测定水中Fe^3＋,Fe^2＋,Cu^2＋,Zn^2＋方法研究

将Dionex 4000i离子色谱仪和国产721分光光度计组合联用,建立了一种同时测定水中Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)四种金属离子的柱后衍生离子色谱法。以磺基水杨酸/酒石酸/草酸为络合剂,质子化的二价乙二胺离子(EnH_2~(2+))为淋洗离子,在Dionex HPIC-CS2分离柱上先实现混合金属离子的分离,之后,各被分离的离子依次进入柱后反应器,与PAR在此反应显色生成有色络合物。借助国产721分光光度计,在500 nm的固定波长下依次检测流出的各离子。Fe~(3+)、Fe~(2+)、Zn~(2+)三种离子仅需6 min就可全部淋洗出。Cu~(2+)在切换淋洗液后检测,也仅需10 min。本法可用于同时测定天然水(mg/L级浓度)和电站高纯水(μg/L级浓度)以及金属腐蚀产物中的Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)。进样分析前,仅需将水样酸化和过滤即可。     

Transport selectivity of carbonate and chloride ions througha strongly alkaline anion-exchange membrane before and after its modification with sodium alginate

The transport selectivity of carbonate ions relative to chloride ions \(\left( {P_{Cl^ - }^{CO_3^{2 - } } } \right)\) through an anion-exchange membrane during electrodialysis is investigated before and after the membrane was modified by the electrolytic precipitation of sodium alginate on its surface, as well as by pretreating the membrane in a solution of sodium alginate. It is established that the experimental value of \(P_{Cl^ - }^{CO_3^{2 - } } \) is appreciably smaller than the calculated value for the unmodified membrane at low values of current density. At large currents the calculated value of \(P_{Cl^ - }^{CO_3^{2 - } } \) is 0.83, and the experimental value is 0.64. During electrodialysis of the working solution, which contains sodium alginate at a concentration of 1–2 g l^?1, \(P_{Cl^ - }^{CO_3^{2 - } } \) decreases by 2–3 times in the current-density range 0.25–1 A dm^?2. Pretreatment of the membrane in a solution of sodium alginate having a concentration of 10 g l^?1 for 72 h decreases \(P_{Cl^ - }^{CO_3^{2 - } } \) from 0.50 (unmodified membrane) to 0.35.     

Preparation and characterization of sulfonated poly(phenylene oxide) proton exchange composite membrane doped with phosphosilicate gels

A new class of proton exchange composite membranes made by incorporating phosphosilicate gels into SPPO matrix was prepared and characterized. The thermal stability was evaluated by TGA and DSC, and the amorphous structure information was provided from XRD. The experimental results showed that the composite membranes have good stability to oxidation by Fenton's reagent test, and the membrane dimension is hardly changed, even at high temperature. The hydration number values of the persulfonic acid group of composite membranes were lower than that of Nafion 112 at room temperature, but the water uptake of composite membranes at 80°C was higher than that of Nafion 112. With increasing relative humidity and doping amount, the conductivity of the composite membranes increased. Moreover, the conductivities of water-equilibrated composite membranes were higher than that of Nafion 112 (0.0871 S/cm) at room temperature, and the highest conductivity for the composite membrane was 0.216 S/cm. Copyright © 2007 John Wiley & Sons, Ltd.     

Fabrication and characterization of a novel TiO2 nanoparticle self-assembly membrane with improved fouling resistance

A novel TiO₂ nanoparticle self-assembly membrane was prepared based on ultrahigh molecular weight poly(styrene-alt-maleic anhydride)/poly(vinylidene fluoride) (SMA/PVDF) blend membrane. TiO₂ nanoparticle solution was beforehand prepared via the controlled hydrolysis of titanium tetraisopropoxide. The diameter (10 nm or less) and anatase crystal structure were analyzed using transmission electron microscopy (TEM) and X-ray diffraction (XRD). The SMA/PVDF blend membranes prepared by the phase inversion method were immersed into the TiO₂ nanoparticle solution for a week to produce TiO₂ self-assembly membranes. The chemical compositions in membrane surface were analyzed by X-ray photoelectron spectroscopy (XPS). The membrane morphologies were measured by scanning electron microscopy (SEM). Finally, the membrane hydrophilicity, protein anti-fouling property and the molecular weight cutoff (MWCO) were characterized by water contact angle measurement, static protein absorption and filtration experiments, respectively. It is demonstrated that, in comparison to PVDF/SMA blend membrane, the permeability and anti-fouling ability of TiO₂ self-assembly membranes were significantly improved.     

The formation of sparingly soluble species of Ca(2+) with carboxylic ligands: speciation and thermoanalysis

This work reports the results of studies into the solubility and thermal decomposition of various sparingly soluble complexes of calcium with two isomeric benzene tricarboxylates, and with benzene penta- and hexa-carboxylates. The dependence of their solubility on ionic strength and, for the calcium benzene hexacarboxylate, the dependence of solubility on Na⁺ concentration in solution were studied. Comparison between structure and solubility of the calcium insoluble compounds here and previously studied, is also reported. In order to perform solubility calculations, we determined also the formation constants of trimellitic and trimesic anions with H⁺, Na⁺ and Ca²⁺ potentiometrically (H⁺-ISE), since these are not reported in literature. All solid compounds were characterised by TG-FTIR measurements, and comparable behaviours in thermal decomposition as a function of ligand structure were found.     

Transport and separation of Ag(+) and Zn(2+) by donnan dialysis through a monovalent cation selective membrane

Donnan Dialysis of Ag⁺ and Zn²⁺ was investigated through a cation exchange membrane (CMS Neosepta) when a proton concentration difference was maintained between the two sides of the membrane. Developed for the production of brine from sea water, CMS Neosepta showed a higher permeability to monovalent than to bivalent cations. Several physico-chemical parameters have been determined (electrical resistance, membrane potential, sorption of electrolytes, Zn²⁺ and Ag⁺ diffusion coefficients). The flux of Ag⁺ and the diffusion potential in the membrane increase with HNO₃ concentrations. Ag⁺ and Zn²⁺ can be separated because of the preferential membrane transfer for Ag⁺.     

Synthesis,characterization, and antibacterial activity of organotin(IV) complexes with 2-hydroxyacetophenone thiocarbohydrazone

Six new organotin(IV) complexes were synthesized by direct reaction of RSnCl₃ (R?=?Me, Bu and Ph) or R₂SnCl₂ (R?=?Me, Bu and Ph) and 2-hydroxyacetophenone thiocarbohydrazone [H₂APTC] under purified nitrogen in the presence of base in 1?:?2?:?1 molar ratio (metal: base: ligand). Complexes 2–7 have been characterized by elemental analyses, molar conductivity, UV-Visible, IR and ¹H NMR spectral studies. Complexes 2–7 are non-electrolytes. The molecular structure of [Me₂Sn(APTC)]?·?(C₂H₅OH) (5) has been determined by X-ray diffraction analysis. The thiocarbohydrazone ligand (1) and 2–7 have been tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi and Enterococci aeruginosa.     

Synthesis and antibacterial activities of copper(II) with [(2-hydroxy-3,5-diiodo-benzylidene)-amino]-acetic acid

A new tridentate ligand, [(2-hydroxy-3,5-diiodo-benzylidene)-amino]-acetic acid (HDBA), has been synthesized from 3,5-diiodosalicylaldehyde and glycine in ethanol. A 1-D coordination polymer has been synthesized by reaction of HDBA with Cu(Ac)₂ · H₂O in ethanol–water. The complex was characterized by UV, IR, ESI–MS, elemental analyses, and X-ray crystallography. The central copper(II) is five-coordinate by one nitrogen and two oxygens from HDBA, one oxygen from water, and one oxygen from another HDBA. The complex was assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae) activities by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Complex 1 showed favorable antimicrobial activity with minimum inhibitory concentrations of 6.25, 6.25, 3.125, 6.25, 6.25, and 3.125 µg mL^?1 against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Synthesis and crystal structures of N,N'-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine and its dinuclear manganese(III) complex with antibacterial activities

A new dinuclear manganese complex, [Mn₂L₂(N₃)₂], was prepared by reaction of bis-Schiff base N,N'-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine (H₂L) with manganese acetate and sodium azide in methanol. Both the Schiff base and the complex were characterized by physico-chemical methods and single crystal X-ray determination. The Schiff base crystallized in the orthorhombic space group Pbca with unit cell dimensions a?=?7.3191(7)?Å, b?=?6.0948(6)?Å, c?=?35.382(3)?Å, V?=?1578.3(3)?ų, Z?=?4, R₁?=?0.0481, wR₂?=?0.1488. The manganese complex crystallized in the monoclinic space group P2₁/c with unit cell dimensions a?=?8.802(1)?Å, b?=?14.928(2)?Å, c?=?14.478(2)?Å, β?=?105.517(2)°, V?=?1833.0(4)?ų, Z?=?2, R₁?=?0.0768, wR₂?=?0.1640. There are crystallographic inversion centers in both the ligand and the complex. The ligand coordinates to Mn through all the phenolate oxygens and imino nitrogens. The two Mn in the complex are bridged by two phenolate oxygens with separation of 3.549(1)?Å. Each Mn is octahedral with four donors of the Schiff base ligand defining the equatorial plane, and with one azido nitrogen and one phenolate oxygen of an adjacent Schiff base ligand occupying the axial positions. The Schiff base and the complex were tested in vitro for their antibacterial activities.     

Transport of Ca^2＋ Ion through a Bubbling Pseudo—emulsion Liquid Membrane with Calixarenes and Calixcrowns as Carriers

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Syntheses, structures and properties of dinickel(II) macrocyclic complexes with two 2-thiophenoethyl pendant arms

Three dinickel(II) macrocyclic complexes [Ni₂L(μ-OAc)]ClO₄•X (L = L¹, L² and L³) with two 2-thiophenoethyl pendant arms, have been synthesized by cyclocondensation between N,N-bis(3-aminopropyl)-2-thiophenoethylamine and 2,6-diformyl-4-R-phenol (where R = Me, Cl and F and X = MeOH, 2MeCN and H₂O, respectively), in the presence of nickel(II) ions. The complexes were characterized by elemental analysis, spectroscopic methods and X-ray diffraction techniques. The geometry around both of the Ni(II) ions in each molecule is a slightly distorted octahedral and the thiopheno groups do not coordinate to the Ni(II) ions, resulting that the complexes display contorted saddle-form configurations. The distances between the Ni?Ni centers for the complexes are 3.145, 3.171 and 3.155 Å, respectively. The influences of the substituted groups R in the benzene rings of the macrocyclic units on the structure, electrochemistry, magnetism, cleavage and antibacterial property to DNA have been investigated. The ES-MS results of the complexes confirm that [Ni₂L]²⁺ species in methanol solution are very stable because all the peaks in ES-MS spectra contain this kind of units. The reduction potentials of the complexes shift towards anode upon increasing the drawing electronic ability of substituted groups. Magnetic measurements in the 2-300 K range indicate weak antiferromagnetism for the dinuclear Ni(II) complexes and the magnetic exchange interactions enhance with the decrease of the Ni-Ni distances. These complexes exhibit cleavage activities towards plasmid pBR322 DNA and antibacterial activities.     

Ni(II) and Cu(II) complexes of new unsymmetrical N2O2 Schiff bases derived from 3-(2-aminobenzylimino)-1-phenylbutan-1-ol: synthesis,structure, antibacterial properties,and electrochemistry

Two new N₂O₂ unsymmetrical Schiff bases, H₂L¹ = 3-[({o-[(E)-(o-hydroxyphenyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol and H₂L² = 3-[({o-[(E)-(2-hydroxy-1-naphthyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol, and their copper(II) and nickel(II) complexes, [CuL¹] (1), [CuL²] (2), [NiL¹] (3), and [NiL²] (4), have been synthesized and characterized by elemental analyses and spectroscopic methods. The crystal structures of these complexes have been determined by X-ray diffraction. The coordination geometry around Cu(II) and Ni(II) centers is described as distorted square planar in all complexes with the CuN₂O₂ coordination more distorted than the Ni ones. The electrochemical studies of these complexes indicate a good correlation between the structural distortion and the redox potentials of the metal centers. The ligand and metal complexes were also screened for their in vitro antibacterial activity.