Ethylenediamminetetraacetic Acid Research Articles

Experimental and DFT studies on complexation of uranyl with N-(2-Hydroxyethyl)iminodiacetic acid in aqueous medium

The nuclear decontaminating agents such as ethylenediamminetetraacetic acid (EDTA), picolinic acid, nitrilotriacetic acid (NTA) and citric acid are co-disposed with the nuclear waste at the storage sites. The thermal, catalytic and radiolytic degradation of this organic waste results in the formation of N-(2-Hydroxyethyl)iminodiacetic acid (HEIDA-H2) as one of the major degradation product. The knowledge on chemical speciation and aqueous thermodynamics of radionuclides in presence of organic chelates is a key input to the codes for framing safe and strategic disposal of radioactive waste. Present work aimed at the determination of thermodynamic parameters (log K, ΔG, ΔH and ΔS), speciation diagram, spectroscopic properties and structural analysis for UO22+-HEIDA complexes in aqueous solution. UO22+ forms ML and ML2 type of species with HEIDA as determined by potentiometry and further corroborated by absorption and luminescence spectroscopy. The Electrospray ionization mass spectrometry (ESI-MS) studies also identified the ML and ML2 complexes. In addition, the difference in the complexation behavior of UO22+ with HEIDA and IDA; which differ by hydroxyethyl substitution on imino nitrogen is explained on the basis of thermodynamic parameters. The 1:1 UO22+-HEIDA complex is exothermic formation while the 1:1 UO22+-IDA complexes are endothermic formations. The differences in enthalpy and entropy of formations are interpreted to reveal the role of hydroxyethyl group on UO22+- HEIDA complexation. NMR studies are carried to elucidate the structures of 1:1 and 1:2 UO22+-HEIDA complexes. The comparison of log K values with structurally similar ligands and NMR spectroscopic studies suggested the tridentate nature for HEIDA. The hydroxyethyl group was found to be uncoordinated with UO22+. The theoretical studies showed the indirect participation of hydroxyethyl group on complexation by charge polarization and by steric influence on coordinating groups.

Molecular and microscopic detection of Theileria luwenshuni infection in goats in and around Guwahati of Assam, India

ABSTRACT Theileriosis, an important tick-borne hemoprotozoan disease that can reduce production and productivity, results in severe economic loss in goat industry. Due to lack of facilities and interest of the researchers the sub-clinical form of theileriosis caused by Theileria luwenshuni was under diagnosed in Assam, India. Therefore, a study was carried out to determine the prevalence of theileriosis in goats from Kamrup (Metro) district of Assam. A total of 454 blood samples collected from goats revealed 39.87 % (181/454) infection with Theileria sp. The genomic DNA extracted from blood samples amplified for a fragment of 18S ribosomal RNA (18S rRNA) gene employing polymerase chain reaction (PCR) using Theileria genus specific primers showed distinct bands at 1098 bp in agarose gel. The resultant PCR products were sequenced and BLAST analysis indicated 99.9% homology with T. luwenshuni. Parasitological methods and PCR technique followed by sequence analysis suggest infection with T. luwenshuni was associated with theileriosis in investigated goats. The results of the present study showed PCR to be more efficient in detection of Theileria positive cases than the microscopic method. Abbreviations: rRNA: Ribosomal ribonucleic acid; PCR: polymerase chain reaction; ml: milliliter; EDTA: Ethylene Diammine Tetraacetic Acid; °C: degree Celsius; DNA: Deoxyribonucleic acid; ME: microscopic examination; sp.: species; V-volt; µg: micro gram; TAE: Tris-acetate-EDTA; F: forward; R: reverse; NCBI: National Center for Biotechnology Information; BLAST-n Basic Local Alignment Search Tool for nucleotide.

A novel phenomenon of effect of metal on calcium carbonate scale, morphology, polymorphism and its deposition

Calcium carbonate scale deposition from its sludge on aluminium metal surface was studied and compared with copper. Ethylenediamminetetraacetic acid (EDTA) was used as a scale inhibitor and the experiments were carried out at 60 and 100 °C. The samples were characterised by XRD, FTIR and SEM techniques. The study revealed that the deposition of scale on the substrate is not only influenced by the chelating agent and temperature but also depends on the type of metal. This phenomenon of metal-induced polymorphic stabilisation and morphological changes has so far been not reported and the possible mechanism is discussed.

A novel rhombohedron-like nickel ferrite nanostructure: Microwave combustion synthesis, structural characterization and magnetic properties

Abstract Research on nickel ferrite nanostructures has drawn a great interest because of its inherent chemical, physical and electronic properties. In this study, we have synthesized rhombohedron – like nickel ferrite nanostructure by a rapid microwave assisted combustion method using ethylenediamminetetraacetic acid as a chelating agent. X-ray diffraction, Fourier transform infrared spectrometer, transmission electron microscope and energy dispersive X-ray microanalyser were used to characterize the prepared sample. The magnetic behaviour was analysed by means of field dependent magnetization measurement which indicates that the prepared sample exhibits a soft ferromagnetic nature with saturation magnetization of 63.034 emu/g. This technique can be a potential method to synthesize novel nickel ferrite nanostructure with improved magnetic properties.

CaCO3 scale deposition on copper metal surface; effect of morphology, size and area of contact under the influence of EDTA

CaCO3 scale deposition from its sludge was studied on copper substrate. Ethylenediamminetetraacetic acid was used as chelating agent and tested for its influence on the deposition. The experiments were carried out at 60 and 100°C and the effect of direct heating and indirect heating was studied. The samples were characterized by XRD, FTIR and SEM techniques. The data revealed that the complex forming nature of EDTA, the shape of the crystallite and area of contact are the key factors for the deposition of CaCO3 on metal surface.

Polymorphic and Morphological Transformations of CaCO<sub>3</sub> under CO<sub>2</sub> Atmosphere and under the Influence of EDTA at 60 °C

Calcium carbonate scale samples were synthesized from calcium chloride solution in the presence of ethylenediamminetetraacetic acid (EDTA) by bubbling CO2 gas. Samples were prepared with different concentrations of EDTA at 60 °C and characterized using XRD, FTIR and SEM techniques. The details revealed that EDTA stabilizes aragonite more efficiently at higher concentrations of EDTA. It was also observed that increasing the concentration of EDTA has no significant impact on the polymorphic specificity where as influence the morphology and the size of the particles.

Polymorphic and Morphological Transformations of CaCO<sub>3</sub> under CO<sub>2</sub> Atmosphere and under the Influence of EDTA at 60 °C

Calcium carbonate scale samples were synthesized from calcium chloride solution in the presence of ethylenediamminetetraacetic acid (EDTA) by bubbling CO2 gas. Samples were prepared with different concentrations of EDTA at 60 °C and characterized using XRD, FTIR and SEM techniques. The details revealed that EDTA stabilizes aragonite more efficiently at higher concentrations of EDTA. It was also observed that increasing the concentration of EDTA has no significant impact on the polymorphic specificity where as influence the morphology and the size of the particles.

Exogenous application of ethylenediamminetetraacetic acid enhanced phytoremediation of cadmium by Brassica napus L.

Performance of B. napus in phytoextraction—an in situ environment friendly technique for the cleanup of contaminated soils—was evaluated through its response to cadmium (Cd) toxicity in combination with a chelator ethylenediamminetetraacetic acid (EDTA) while growing hydroponically in greenhouse conditions under three levels of Cd (0, 10, and 50 µM) and two levels of EDTA (0 and 2.5 mM). Cadmium presence decreased plant growth, biomass and chlorophyll concentrations, while the application of EDTA enhanced plant growth by reducing Cd-induced effects in Cd-stressed plants. Addition of EDTA improved the net photosynthetic and gas exchange capacity of plants under Cd stress. Presence of Cd at 10 and 50 μM significantly increased electrolyte leakage, the production of hydrogen peroxidase (H2O2) and malondialdehyde (MDA) resulting into a significant reduction in the activities of catalase, guaiacol peroxidase, ascorbate peroxidase and superoxide dismutase in Cd-stressed plants. Application of EDTA at the rate of 2.5 mM alone and with combination of Cd increased the antioxidant enzymes activities and reduced the electrolyte leakage and production of H2O2 and MDA. The B. napus actively accumulated Cd when applied with EDTA in roots, stems and leaves viz. 2817, 2207 and 1238 mg kg−1 DW, respectively, at higher Cd level (50 μM) followed by lower level of Cd (10 μM) viz. 1704, 1366 and 763 mg kg−1 DW, respectively. Results showed that this technique could be useful for the remediation of heavy metal-contaminated agricultural and industrial soils.

Rising Antimicrobial Resistance of Pseudomonas aeruginosa Isolated from Clinical Specimens in India

The rising antibiotic resistance against commonly used drugs is of great concern. Drug susceptibility testing and Polymerase Chain Reaction (PCR) assay were used to determine the antibiotic susceptibility patterns and prevalence of genes encoding extended-spectrum-β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) among 515 isolates of Pseudomonas aeruginosa isolated from various clinical specimens. Susceptibility of isolates to seven antibiotics was tested using disc diffusion method according to the guidelines defined by Clinical Laboratory Standard Institute. Isolates showing resistance to any of the two cephalosporins (ceftriaxone, ceftazidime and cefotaxime) were subjected to PCR for the prevalence of ESBL and MBL gene characterization. Out of the 515 isolates, 235 (45.63%) were considered as ESBL positive; 87 (16.89%) were MBL positive and 74 (14.36%) had co-produced both ESBL and MBL. The frequency of TEM-type, SHV-type and AMP-C type ESBLs were 45.10, 26.0, and 28.93%, respectively. Among the MBLs, the frequency of distribution of NDM-1, IMP-1 and VIM-1 was 24.13, 28.73 and 47.12%, respectively. The rate of susceptibility of ESBL producing P. aeruginosa towards various antibacterial agents were as follows: piperacillin+tazobactam (84.3%), doripenem (83.8%), ceftriaxone plus ethylenediamminetetraacetic acid plus sulbactam; Elores (74.1%), imipenem (66.5%), meropenem (54.7%), ceftazidime (44.8%) and cefepime (28.5%). Isolates harboring MBL and ESBL+MBL genes were resistant to almost all antibiotics except Elores (97.3 and 95.1% susceptibility) and doripenem (11.3 and 19.5% susceptibility). From the above results, it can be concluded that Elores was highly potent against MBL producing P. aeruginosa. However, suceptibility of Elores to ESBL producing P. aeruginosa was comparable to piperacillin plus tazobactam.

Spectrofluorometric study of iron removal from bovine lactoferrin by ethylenediamminetetraacetic acid

The kinetics of iron removal from the two metal binding sites of the bovine lactoferrin by ethylenediaminetetraacetic acid (EDTA) was investigated at pH 7.5 and 33 °C. Solutions were buffered at pH 7.5 by 0.15 M Tris–HCl. Pseudo first-order rate constants as a function of ligand concentration were measured for iron removal from diferric lactoferrin and from N- and C-terminal monoferric lactoferrin. Diferric lactoferrin showed simple saturation behavior while both the monoferric forms showed a two-term dependence of k obs on ligand concentration that signifies two pathways for iron removal under the conditions applied. Moreover, the results show that the N-terminal site is more labile towards iron removal by EDTA than the C-terminal site.

Inhibition of Aluminium Alloy AA2024-T3 pitting corrosion by copper complexing compounds

A scanning vibrating electrode technique (SVET) is used to quantify the influence of a range of copper complexing/precipitating reagents on the kinetics of pitting corrosion affecting AA2024-T3 immersed in 5% aqueous sodium chloride (NaCl). It is shown that organic anions such as 2,5 dimercapto, 1,3,4 thiadiazolate (DMTD), benzotriazolate (BTA) and N,N- diethyl, dithiocarbamate (DEDTC), and inorganic ions such as ferrocyanide effectively inhibit pitting corrosion by film formation on Cu rich intermetallic particles (IMPs) and/or precipitation of aqueous copper cations. Inhibitor efficiency increases in the order ferrocyanide < BTA < DEDTC ≈ DMDT. In contrast, the presence of ethylenediamminetetraacetic acid (EDTA) is shown to prevent copper (Cu) replating, but does not lead to any decrease in localised corrosion currents. This supports the idea that that ample cathodic activity can be maintained on Cu-rich IMPs in the absence of any copper replating to sustain stable pitting on AA2024.

Kinetics and Mechanism of Paracetamol Oxidation by Chromium(VI) in Absence and Presence of Manganese(II) and Sodiumdodecyl Sulphate

The kinetics of paracetamol oxidation are first order each in [paracetamol] and [HClO4]. The kinetic study shows that the oxidation proceeds in two steps. The effects of anionic micelles of sodiumdodecyl sulphate (SDS) and complexing agents (ethylenediammine tetraacetic acid (EDTA) and 2,2′-bipyridyl (bpy)) were also studied. Fast kinetic spectrophotometric method has been described for the determination of paracetamol. The method is based on the catalytic effect of manganese(II) on the oxidation of paracetamol by chromium(VI) in the presence of HClO4 (= 0.23 mol dm−3). Optimum reaction time is 4 to 6 minutes at a temperature of 30∘C. The addition of manganese(II) ions largely decreased the absorbance of chromium(VI) at 350 nm. This reaction can be utilized for the determination of paracetamol in drugs.

Carnein, a Serine Protease from Noxious Plant Weed Ipomoea carnea (Morning Glory)

A new serine protease from the latex of Ipomoea carnea spp. fistulosa (Morning glory), belonging to the Convolvulaceae family, was purified to homogeneity by ammonium sulfate fractionation followed by cation exchange chromatography. The enzyme, named carnein, has a molecular mass of 80.24 kDa (matrix-assisted laser desorption/ionization time-of-flight) and an isoelectric point of pH 5.6. The pH and temperature optima for proteolytic activity were 6.5 and 65 degrees C, respectively. The extinction coefficient (epsilon2801%) of the enzyme was estimated as 37.12, and the protein molecule consists of 35 tryptophan, 76 tyrosine, and seven cysteine residues. The effect of several inhibitors such as iodoacetic acid, diisopropylfluorophosphate, phenyl-methanesulfonyl fluoride, chymostatin, soybean trypsin inhibitor, HgCl2, 3S-3-(N-{(S)-1-[N-(4-guanidinobutyl)carbamoyl]3-ethylbutyl}carbamoyl)oxirane-2-carboxylic acid, N-ethyl maleimide, ethylene glycol-bis(alpha-amino ethyl ether)tetraacetic acid, ethylenediamminetetraacetic acid, and o-phenonthroline indicates that carnein belongs to the family of serine proteases. The enzyme is not prone to autolysis even at very low concentrations. The N-terminal sequence of carnein (T-T-H-S-P-E-F-L-G-L-A-E-S-S-G-L-X-P-N-S) exhibited considerable similarity to those of other plant serine proteases; the highest similarity was with alnus AG12, one of the subtilase family endopepetidases.

Determination of Ultra Trace Level of Uranium in Ground Water of Different Geo-Chemical Environment by Adsorptive Stripping Voltammetry

The mineral mobilisation in ground water due to rock water interaction largely depends on the localized subsurface geo-chemical environment. During this work, traces of uranium were measured by adsorptive stripping voltametry (AdSV) in groundwater having various level of dissolved minerals. Experimental solutions were prepared in the laboratory by spiking natural groundwater with standard solutions of major cations (Ca2+, Mg2+, K+), anions (Cl−1, F−1, and \( {\text{PO}}^{{3 - }}_{4} \)), trace metal ions (Cu and Pb) and DOC (Dissolved Organic Carbon). The concentrations of these anions, cations and DOC in subsurface water changes due to changes in the geo-chemical environment at different locations. Experimental results show that major anions do not have any pronounced impact on the analysis of uranium. In the case of cations, only Cu2+ shows strong interferences. However addition of 2% Ethylene Diammine Tetra-acetic Acid (EDTA) solution in the ratio of 1:25 removes interference due to copper upto a concentration of <0.2 ppm. Interference with copper was also studied by varying the accumulation potential, pH and concentration of chloroanilic acid. Though no interferences were observed in ground water having dissolved organic carbon (DOC) in the range of 0.01–15 ppm, between 15–16 ppm of DOC, the ability to detect uranium by AdSV decreases sharply. Further, if DOC exceeded 16 ppm it was not possible to do the analysis of uranium by AdSV without destruction of DOC, as DOC is a surface active organic compound and accumulates on Hg electrode preferentially over uranium-chloroanilic complex.

Enhancement of crystalline perfection by organic dopants in ZTS, ADP and KHP crystals as investigated by high-resolution XRD and SEM

To reveal the influence of complexing agents on crystalline perfection, tristhiourea zinc(II) sulfate (ZTS), ammonium dihydrogen phosphate (ADP) and potassium hydrogen phthalate (KHP) crystals grown by slow-evaporation solution growth technique using low concentrations (5 × 10−3M) of dopants like ethylenediamminetetraacetic acid (EDTA) and 1,10-phenanthroline (phen) were characterized by high-resolution X-ray diffractometry (XRD) and scanning electron microscopy (SEM). High-resolution diffraction curves (DCs) recorded for ZTS and ADP crystals doped with EDTA show that the specimen contains an epilayer, as observed by the additional peak in the DC, whereas undoped specimens do not have such additional peaks. On etching the surface layer, the additional peak due to the epilayer disappears and a very sharp DC is obtained, with full width at half-maximum (FWHM) of less than 10 arcsec, as expected from the plane wave dynamical theory of X-ray diffraction for an ideally perfect crystal. SEM micrographs also confirm the existence of an epilayer in doped specimens. The ZTS specimen has a layer with a rough surface morphology, having randomly oriented needles, whereas the ADP specimen contains a layer with dendric structure. In contrast to ADP and ZTS crystals, the DC of phen-doped KHP shows no additional peak, but it is quite broad (FWHM = 28 arcsec) with a high value of integrated intensity, ρ (area under the DC). The broadness of the DC and the high value of ρ indicate the formation of a mosaic layer on the surface of the crystal. However, similar to ADP and ZTS, the DC recorded after etching the surface layer of the KHP specimen shows a very sharp peak with an FWHM of 8 arcsec. An SEM photograph of phen-doped KHP shows deep cracks on the surface, confirming the mosaicity. After removing the surface layer, the SEM pictures reveal a smooth surface. A similar trend is observed with other complexing agents, like oxalic acid, bipy and picolinic acid. However, only typical examples are described in the present article where the effects were observed prominently. The investigations on ZTS, ADP and KHP crystals, employing high-resolution XRD and SEM studies, revealed that some organic dopants added to the solution during the growth lead to the formation of a surface layer, due to complexation of these dopants with the trace metal ion impurities present in the solution, which prevents the entry of impurities, including the solvent, into the crystal, thereby assisting crystal growth with high crystalline perfection. The influence of organic dopants on the second harmonic generation efficiency is also investigated.

Effect of organic dopants on ZTS single crystals

The influence of organic dopants on tristhioureazinc(II)sulphate (ZTS) single crystals from aqueous solutions at 30 °C is investigated. The dopants used in the present investigation are disodium salt of ethylenediamminetetraacetic acid (EDTA), benzene and 1,10-phenanthroline (Phen) which are having different structures. Though, all the dopants show better results, prominent influence is observed in case of EDTA dopant with low concentration of 5×10 −3 M L −1 and hence the results pertaining to EDTA dopant are described in detail in the present article. At low concentrations of dopant, an increase in the metastable zone width, leading to an increase in the crystal growth rate is observed. At higher dopant concentration, growth rate decreases. The crystalline perfection of the grown crystals has been evaluated by high-resolution X-ray diffractometry (HRXRD). The diffraction curve (DC) of a typical EDTA-doped as-grown ZTS crystal was observed to contain one additional peak very close to the main peak suggesting the possibility of an epitaxial layer on the surface of the crystal. After removing this layer by lapping followed by chemical etching, the DC was found to contain only a single and very sharp peak showing that the main crystal is having a much better crystalline perfection than that observed for the specimen grown with out using any dopant in the solution. This indicates that the complexation of trace metal ion impurities (present in the solution) with the dopants is responsible for the formation of the layer on the surface of the crystal and prevents the entry of impurities in the growing crystal. The complexation also promotes the growth process leading to a rapid growth with high crystalline quality. Not much variation is observed in FT-IR and XRD of pure and doped ZTS. However, second harmonic generation (SHG) efficiency measurements carried out with different dopants reveal that nonlinear optical (NLO) property is enhanced by EDTA and benzene dopants. However, Phen depresses the NLO efficiency of ZTS.

Fluorescence studies of ternary complexes of Europium and Terbium and their application to analytical determinations

Europium and Terbium were found to form ternary complexes with ethylenediammine tetraacetic acid (EDTA) and ortho-phenanthroline (o-phen) in aqueous solution in the pH range of 6–8. These ternary complexes were found to have 1:1:1 composition and showed strong fluorescence properties. The method is made use of for the determination of these lanthanide ions in presence of excess amounts of other lanthanide ions. The lowest detection limit was calculated as 30 and 65ng/ml of Tb3+ and Eu3+, respectively.

Effects of EDTA on the electronic properties of passive film on Fe–20Cr in pH 8.5 buffer solution

Effects of EDTA (ethylene diammine tetraacetic acid) on the electronic properties of passive film formed on Fe–20Cr alloy in pH 8.5 buffer solution were examined by the photo-electrochemical and impedance techniques to elucidate the structure and composition of passive film on the alloy. XPS composition profile in depth for the passive film revealed that Cr content in the outermost layer of the passive film was higher for the passive film formed in the solution containing EDTA than that in solution without EDTA, due presumably to the selective dissolution of Fe oxide by EDTA. In spite of the selective dissolution of Fe oxide in the outer layer of the passive film, the photocurrent spectra and the Mott–Schottky plots for the passive film formed on Fe–20Cr in EDTA containing solution were very close to those in EDTA-free solution, which strongly supports that the passive film on Fe–20Cr in pH 8.5 buffer solution is a single layered Cr-substituted γ-Fe 2O 3 oxide rather than a duplex layered oxide composed of inner Cr oxide and outer Fe oxide.

Backscattered electron imaging of crystal matrix protein on the surface of calcium oxalate crystals using colloidal gold.

In order to clarify the presence and localization of crystal matrix protein (CMP) upon calcium oxalate crystals, scanning electron microscopy (SEM) and backscattered electron imaging (BEI) techniques were used. This protein exhibits a remarkable affinity with calcium oxalate crystals and may be important in stone pathogenesis. In this paper, rabbit anti-human CMP polyclonal antibody was used as first antibody, and for the second antibody, goat anti-rabbit IgG conjugated with 20 nm immunogold was used. Freshly prepared crystals from male urine were fixed in SEM fixative, then blocked and washed with phosphate-buffered saline and bovine serum albumin (PBS/BSA). First and second antibodies were reacted in PBS/BSA. Crystals were then dehydrated and finally coated for SEM study. The SEM technique showed bipyramidal shaped dihydrate calcium oxalate crystals in every sample and even at high magnification, colloidal gold could barely be seen. BEI clearly demonstrated the presence and localization of the gold on the surface of the crystals as well as on the macromolecules eluted from the crystals by dissolving them in ethylenediamminetetraacetic acid solution.

Electrodeposition of BiSrCaCu alloyed films from non-aqueous bath

The electrodeposition of BiSrCaCu alloyed films from non-aqueous bath was carried out onto fluorine doped tin oxide (FTO) coated MgO substrates. The BiSrCaCu complex was formed with sodium citrate, Ethylenediammine tetraacetic acid (EDTA), tartaric acid, and sodium nitrate. Black coloured deposits of BiSrCaCu with thickness of 4–6 μm were obtained for the deposition period of 30 minutes. The effect of complexing agents and other preparative parameters on electrodeposition potentials and consequently on microstructural properties are studied. The oxide films showed superconductivity with onset and zero resistivity temperatures of 95 K and 76 K respectively.