Determination of NTA in Environmental Water by gas Chromatography

Abstract

A rapid, sensitive gas chromatographic method for the determination of NTA as its trimethylsilyl ester has been developed. The method is not subject to interference by common cations, a wide variety of anions, or other aminopolycarboxylate chelating agents. Satisfactory determinations of NTA in the low ppm range have been carried out in artificial standards, spiked river water and bacterial growth media. The method is suitable for following biological degradation of NTA.     

Determination of ethylenediaminetetraacetate and nitrilotriacetate in phytoplankton media by differential pulse polarography

A technique for the analysis of synthetic sea water and phytoplankton media for ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA) by differential pulse polarography has been developed. The addition of approximately 2.4 · 10^-4 M cadmium to the analyte converts a large fraction of either ligand to the reducible cadmium complex. With 5 · 10^-6 M ligand present, the standard deviation is approximately. 6 · lO^-7 M for NTA and 4 · 10^-7 M for EDTA. The presence of competing metal cations, including copper, is not detrimental if the method of standard additions is used.     

Determination of Phosphate in Aqueous Solutions Containing NTA and EDTA

Abstract

A simple and precise colorimetric method of determining phosphate in aqueous solutions containing nitrilotriacetic acid (NTA) or ethylendiaminetetraacetic acid (EDTA) is described. It involves precipitation of the NTA or EDTA by acidification to pH 1.5 and colorimetric determination of the phosphate in the filtrate by a heteropoly blue method. The method is sensitive and accurate, and it permits determination of microgram amounts of phosphate in samples of aqueous solutions containing up to 300 mM of NTA and (or) EDTA.     

Extraction And Spectrophotometric Determination Of Cadmium Based On The Formation Of A Ternary Complex With Cadion And 1, 10-Phenanthroline

Abstract

Cadmium ion reacts with cadion and 1, 10-phenanthroline to form a 1:1:2 orange-red ternary complex in 0.5N sodium hydroxide medium. The complex is extracted by chloroform and has a molar absorptivity of 9.2 × 10⁴ l. mole^?1. cm^?1 at 490 nm. A method is developed for the determination of cadmium in electroplating waste water.     

Spectrophotometric Determination of Cadmium(II) Using p,p′‐Dinitro‐SYM‐Diphenylcarbazid in Aqueous Solutions

Abstract

A sensitive and selective spectrophotometric method is proposed for the rapid determination of cadmium(II) using, p,p′‐dinitro‐sym‐diphenylcarbazid, directly in aqueous solution. The reaction between cadmium(II) and p,p′‐dinitro‐sym‐diphenylcarbazid occurs immediately in strong basic media (0.02 N sodium hydroxide solution). The complex shows a maximum of absorption at 630–640 nm, and the absorbance remains stable for at least 24 h. The method allows the cadmium determination over the range 0.5–6.0 µg mL^?1, with a molar absortivity of 2.05×10⁴ L mol^?1 cm^?1 and features a detection limit of 0.13 ppm. The interferences caused by several ions [Ca(II), K(I), Ba(II), Al(III), Pb(II), Zn(II), Cl^?1, NO₃ ^?, SO₄ ^2?], which are present in most of environmental samples, were determined. The validation of the spectrophotometric method was done by recovery test of cadmium(II) in tap water and sea water. The results show that the proposed method has been successfully applied to the determination of cadmium(II) in water samples.     

The Absolute Thermoelectric Power of Some Dilute Liquid Sodium Alloys

Abstract

The absolute thermoelectric powers of liquid sodium and of dilute liquid alloys of sodium with silver, cadmium, indium and tin have been measured within the temperature range 100–460°C. The thermopower of liquid sodium is decreased by the addition of cadmium, indium or tin, with cadmium having the smallest and indium the greatest effect, whereas it is increased slightly on the addition of 1 at. % of silver. Values of the dimensionless thermopower parameter, ?, derived from the experimental data, are compared with those predicted by the Faber-Ziman theory; the agreement is quite good for Na-Ag and Na-Cd but less satisfactory for Na-In and Na-Sn. The discrepancies are discussed in terms of the assumptions involved in the calculations, namely the use of only one structure factor and local dielectric screening of the ionic pseudopotentials.     

Synthesis,crystal structure,and magnetic properties of a linear trinuclear Cu(II) complex

A new linear trinuclear Cu(II) complex, [Cu₃(NTA)₂(4,4′-bpt)₄(H₂O)₂]?·?10H₂O (H₃NTA?=?nitrilotriacetic acid, 4,4′-bpt?=?4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole) (1), was obtained from evaporation of an aqueous solution containing Cu(NO₃)₂?·?6H₂O, 4,4′-bpt, nitrilotriacetic acid (H₃NTA), and NaOH. 1 was characterized using single-crystal X-ray diffraction, IR, and elemental analysis. In the trimer, the three linear copper ions are bridged by two NTA carboxylate groups in a syn–anti conformation and connected by 4,4′-bpt to produce a 1-D array. Temperature-dependent magnetic susceptibilities reveal the presence of weak antiferromagnetic exchange between metal centers.     

Potentiometric Determination of Nitrilotriacetate in Water and Sewage

Abstract

A potentiometric titration of nitrilotriacetate in wastewater and sewage samples and a procedure of sample treatment to eliminate the interferences are described. T1³⁺ and Cu²⁺ solutions were the titrants and the potentiometric titrations were monitored with a platinum redox electrode. T1³⁺ :2NTA complex formation was found. The lower detection limit was 0. 1 ppm of NTA. The relative standard deviation in sewage samples was 5% and the recovery varied from 90–110%.     

Hydrothermal syntheses,and crystal structures of new lanthanide coordination polymers with nitrilotriacetic acid

Hydrothermal reactions of Nd(ClO₄)₃·6H₂O, Gd(ClO₄)₃·6H₂O and Er₂O₃ with H₃NTA (nitrilotriacetic acid) afford three new lanthanide coordination polymers, {[Nd(NTA)(H₂O)]· 2H₂O} _n (1), {[Gd(NTA)(H₂O)]·2H₂O} _n (2) and {[Er(NTA)(H₂O)]·H₂O} _n (3), characterized by elemental analysis and IR spectroscopy. X-ray single crystal structural analyses showed that 1 and 2 are an isomorphous 2D-layered framework containing the nine-coordinated Nd(III) (or Gd(III)), and woven into a 3D suprastructure by interlayer hydrogen bonding while 3 is a 3D structure with eight-coordinate Er(III).     

CdS Quantum Dots as Fluorescence Probes for the Detection of Selenite

Abstract

Water-soluble cadmium sulfide (CdS) quantum dots (QD) capped by mercaptoacetic acid were synthesized by aqueous-phase arrested precipitation and characterized by transmission electron microscopy, a spectrofluorometer, and an ultraviolet visible (UV-Vis) spectrophotometer. Based on the fluorescence quenching of CdS QD by selenite in the presence of glutathione (GSH), a simple, rapid, sensitive, and selective detection method for selenite was proposed. Under the optimum conditions, the calibration graph was linear in the range of 0.05 µmol L^?1 to 11.2 µmol L^?1. The limit of detection is 0.03 µmol L^?1. The usefulness of the proposed method was evaluated for the determination of selenite in sodium selenite tablet and sodium selenite and vitamin E injection, and the results agreed with the labeled values. In addition, the effect of foreign ions (common anions and biologically relevant cations) on the fluorescence of the CdS QD was examined to evaluate the selectivity. The quenching mechanism is also described.     

Determination and comparison of stability constants of tungsten(VI) and molybdenum(VI) with nitrilotriacetic acid and glutamic acid at different ionic strengths

The formation constants of species formed in the systems H⁺?+?W(VI)?+?nitrilotriacetic acid (NTA) and H⁺?+?NTA have been determined in aqueous solution for pH?=?4–9 at 25°C and different ionic strengths ranging from 0.1 to 1.0?mol?dm^?3 NaClO₄, using potentiometric and spectrophotometric techniques. It was shown that tungsten(VI) forms a mononuclear 1?:?1 complex with NTA of the type WO₃L^3? at pH?=?7.5. The composition of the complex was determined by the continuous variations method. The complexation of molybdenum(VI) with glutamic acid was investigated in aqueous solution ranging in pH from 4 to 9, using polarimetric, potentiometric and spectrophotometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum(VI) forms a mononuclear 1?:?1 complex with glutamic acid of the type MoO₃L^2? at pH?=?6.0. The dissociation constants of glutamic acid and the stability constants of the complex were determined at 25°C and at ionic strengths ranging from 0.1 to 1.0?mol?dm^?3 sodium perchlorate. In both complex formation reactions the dependence of the dissociation and stability constants on ionic strength is described by a Debye-Huckel type equation. Finally, a comparison has been made between the patterns of ionic strength dependence for the two complexes and the results have been compared with data previously reported.     

Hydrothermal synthesis,crystal structure and characterization of a new 1-D supramolecular ladder based on a binuclear CdII complex [Cd2L4(3,5-DNBA)2](H2O) with L as a bridging ligand (L=3-(2-pyridyl)pyrazole; 3,5-DNBA=3,5-dinitrobenzoate)

A new 1-D cadmium(II) mixed ligand dimer supramolecular ladder [Cd₂ L ₄(3,5-DNBA)₂]H₂O (1), (L?=?3-(2-pyridyl)pyrazole and 3,5-DNBA?=?3,5-dinitrobenzoate) was synthesized by hydrothermal methods. X-ray structural analysis of complex 1 revealed that two cadmium(II) cores are bridged by two deprotonated pyrazole groups of L, leading to dinuclear cadmium(II) [Cd₂ L ₄(3,5-DNBA)₂]. The dimers are joined by hydrogen-bonding interactions between two different cadmium(II) dimers to form a one-dimensional ladder-like framework and stabilized by weak π–π interactions. Moreover, the fluorescence spectrum of compound 1 exhibits blue fluorescent emission in the solid state at room temperature.     

SYNTHESIS AND STRUCTURE OF A NEW BINUCLEAR CADMIUM(II) CRYPTATE

Abstract

A new binuclear cadmium(II) cryptate has been synthesized by [2+3] Schiff base condensation of tris(3-aminoethyl)amine (tren) with sodium 2,6-diformyl-4-chlorophenolate in the presence of Cd(ClO₄)₂ · 6H₂O. The crystal structure shows that two cadmium(II) ions are bridged by three μ₂-phenoxy oxygen atoms. Each cadmium(II) is located in a capped triangular prismatic coordination environment (N₄O₃).     

Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium,zinc, and copper determination in freshwaters

This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60–160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach.     

Spectrophotometric Determination of Manganese with 4(5)-Imidazolealdoxime (Imalox)

Abstract

A method is described for the spectrophotometric determination of manganese by means of its complex with 4(5)-imidazolealdoxime, IMALOX, formed in alkaline medium. The colour system has its absorption maximum at 350 nm and obeys Beer's law over the range 0.8–8.0 μg of Mn per ml. The optimum range is 1–5 μg m^?1. The molar absorptivity is 7850 1 mol^?1 cm^?1. Relatively few ions interfere, and these can be masked with cyanide, tartrate and NTA. The experimental results have been critically analyzed and a comparison with the main spectrophotometric reagents for manganese is presented.     

Effect of Some Precipitating and Complexing Agents on the Potential of an Ion-Selective Pb(II) - Electrode

Abstract

The influence of some precipitating and complexing agents on the function of Pb(II)-sensitive electrode was studied. On the basis of the experimental findings, procedures were worked out for determining oxalate, phosphate, chromate, nitrilotriacetic acid (NTA), sodium diethyldithiocarbamate (NaDDC), and diethylenetetraamine penta-acetic acid (DTPA) with a standard Pb(II) solution as a titrant and a Pb(II), -sensitive electrode as a detector. The reverse titration of Pb(II), with any of these agents could also be done.     

Three lanthanide coordination polymers with nitrilotriacetic acid: hydrothermal syntheses,crystal structures and fluorescent property

Hydrothermal reactions of Sm₂O₃, Gd(ClO₄)₃?·?6H₂O and Tb(ClO₄)₃?·?6H₂O with nitrilotriacetic acid, give rise to three lanthanide coordination polymers, {[Sm(NTA)(H₂O)₂]?·?H₂O} _n (1), {[Gd(NTA)(H₂O)]?·?H₂O} _n (2) and {[Tb(NTA)(H₂O)]?·?H₂O} _n (3). Their solid-state structures have been characterized by elemental analysis, and IR spectroscopy. X-ray single-crystal diffraction analyses indicated that 2 and 3 are isomorphous three-dimensional coordination polymers with eight-coordinate Gd(III) (or Tb(III)), while 1 forms a two-dimensional coordination polymer containing nine-coordinate Sm(III). The photophysical properties of 3 have been studied with excitation and emission spectra, which exhibit strong green emission.     

Mobilisationsverhalten von Thallium und Cadmium in einem Flu?sediment

Zusammenfassung An einem kontaminierten Flußsediment wird die Mobilität von Thallium und Cadmium untersucht. Die Metalle sind sehr fest an die Sedimentmatrix gebunden und werden erst unterhalb pH 2 in relevanten Mengen freigesetzt. Die Komplexbildner NTA und HEDP besitzen keinen Einfluß auf die Mobilisierbarkeit beider Metalle. Die Bestimmungen erfolgten durch Flammen-AAS und ET-AAS.

---

Mobilization behaviour of thallium and cadmium in a river sediment

Summary The mobility of thallium and cadmium was studied on a polluted river sediment. The metals are strongly bound to the sediment matrix. They are released in significant amounts beyond pH 2. The complexing agents NTA and HEDP have no influence on the mobilization behaviour of both metals. The determinations were performed by flame AAS and ET-AAS.

---

---

Wir danken dem Fonds der Chemischen Industrie für finanzielle Unterstützung und Herrn Dr. Jakobi (Henkel & Cie. GmbH, Düsseldorf) für die Bereitstellung der Phosphonsäure.     

Kinetically controlled separation of cadmium(II) from zinc(II) with dithizone in the presence of nitrilotriacetic acid.

The extraction rates of cadmium(II) and zinc(II) with dithizone (H2dz) in the presence of nitrilotriacetic acid (NTA) were measured, and the possible kinetic separation of cadmium(II) from zinc(II) was investigated. Upon the addition of NTA, the difference in the extraction rate between cadmium(II) and zinc(II) became large. Based on the observed rate constant under the condition [NTA] = 1 x 10(-2) mol dm-3, [H2dz]org = 1 x 10(-3) mol dm-3, and pH = 7.0, the shaking time required for the quantitative separation of cadmium(II) from zinc(II) was calculated to be between 326 and 995 s. The experimental results agreed with the prediction, and the quantitative separation of cadmium(II) from zinc(II) was performed within the above-mentioned range of shaking times.     

Analytical Properties of 4, 4′-Biazobenzenediazoaminobenzene and its Applications in Spectrophotometry

Abstract

The spectral characteristics and analytical properties of 4, 4′-Biazobenzenediazoaminobenzene as a new chromogenic reagent have been described and the optimum conditions for reaction with eight metal ions are presented. In the presence of Triton X-100 and sodium tetraborate solution, the reagent can be used for the determination of Hg, Ni, Cd. The molar absorptivities are 1.8×10⁵ l.mol^?1. cm^?1 at 515 nm for mercury, 2.0×10⁵ l.mol^?1. cm^?1 at 540 nm for nickel, and 1.8×10⁵ l.mol^?1.cm^?1 at 526 nm for cadmium. The recommended procedure has been used for the spectrophotometric determination of cadmium in waste water.