Potentiometric determination of NTA, EDTA and DTPA in mixtures

Consecutive potentiometric determination of EDTA and NTA or DTPA and NTA is described. The method is based on the titration with iron(III) chloride at pH 4-5 in the presence of a small amount of ferroin and 1,10-phenanthroline which keeps the concentration of free iron(II) ions constant, thus making the potential dependent only on the free iron(III) concentration.     

Quantitative chromatographic method for the determination of low levels of nitrilotriacetic and ethylenediaminetetraacetic acids in diethylenetriaminepentaacetic acid

A quantitative method for determination of low levels (0.05%, w/w) of nitrilotriacetic and ethylenediaminetetraacetic acids in diethylenetriaminepentaacetic acid is described. Palmitic acid is added to the chelator as an internal standard before esterification with methanol containing 2%(v/v)H2SO4. The methyl esters of palmitic, nitrilotriacetic, and ethylenediaminetetraacetic acids are first separated from diethylenetriaminepentaacetate by silicic acid column chromatography and are subsequently quantitated by gas-liquid chromatography. The method is both accurate and reproducible with less than 10% relative error. Thin-layer chromatographic separations of the methyl esters, and quantitation at the 1% level, are also described.     

Gamma radiolysis of nitrilotriacetic acid (NTA) in aqueous solutions

Aqueous solutions of nitrilotriacetic acid (NTA) were irradiated with gamma-rays. In deaerated acidic solutions G (IDA, iminodiacetic acid) was found to be 3.0 and in aerated solutions 2.7. Both H and OH radicals abstracted alpha hydrogen from the NZA molecule. The dehydrogenated radical disproportionated to NTA and IDA; however in presence of air, the radical added with O₂ to give peroxy intermediate which was hydrolyzed to IDA and HO₂. The rate constants, for the reaction of OH-radical with NTA at pH 2.0, 6.0 and 10.0 as determined by competition kinetic methods were 0.61·10⁸, 5.5·10⁸ and 42·10⁸ dm³·mol^–1·s^–1, respectively. These indicated that the unprotonated form of NTA is more reactive than its protonated form. This has been attributed to the deactivation of alpha-hydrogen centers by protons through inductive effect.     

DNA cleavage promoted by diethylenetriaminepentaacetic acid （DTPA） derivatives

DTPA and its two derivatives were synthesized and used as catalysts in DNA cleavage.Under physiological conditions,a series of experiments have been done.The effects of DNA cleavage with three ligands were studied under different concentrations, cleavage time,and pH values.The results strongly suggested that the plasmid DNA(pUC 19) can be cleaved efficiently by CITC-DTPA. For the cleavage reaction catalyzed by CITC-DTPA,FormⅠDNA could convert to FormⅡmostly,and the DNA-cleavage mechanism involved an oxid...     

Convenient synthesis of water-soluble nitrilotriacetic acid (NTA) BODIPY dyes

Mono- and bis-NTA-BODIPY dyes have been efficiently synthesized by amide bond formation between hepta-alkylated meso-aryl-BODIPY derivatives and the free amine of mono- and bis-NTA binder surrogates. These new fluorescent hybrids exhibited valuable photophysical properties under buffered aqueous conditions, thus expanding the arsenal of water-soluble BODIPY dyes for potential labeling and monitoring of biological systems and processes.     

Degradation of nitrilotriacetic acid (NTA) by oxidation with lead dioxide suspension

Degradation of nitrilotriacetic acid (NTA) by oxidation with lead dioxide suspension has been studied by differential pulse polarography. The NTA was degraded over the pH range from 4 to 9, with formation of glycine or a mixture of iminodiacetic acid and glycine. After shaking with lead dioxide for 1 hr at 30 degrees and pH ~7, the NTA was almost completely decomposed, the molar reacting ratio of Pb(IV) to NTA being ~17:1; down to 1 x 10(-5)M NTA was decomposed in a shaking time as short as 15 min and at a temperature as low as 5 degrees . The iron(III)-NTA complex was also degraded under the same conditions, and the iron released was adsorbed on the lead dioxide.     

Simultaneous determination of DTPA,EDTA, and NTA by capillary electrophoresis after complexation with copper

We present a method for simultaneous determination of the aminopolycarboxylic acids DTPA, EDTA and NTA in dishwashing detergents, paper mill waters, and natural waters by capillary electrophoresis (CE). The complexing agents were examined as their copper(II) complexes and separated by conventional CE with reversed polarity of the applied voltage. The optimum separation conditions were established by varying the pH and phosphate and tetradecyltrimethylammonium bromide (TTAB) concentrations in the run buffer. The separations were carried out in a fused-silica capillary (61 cm×75 m i.d.) filled with phosphate buffer (80 mmol L^–1, TTAB concentration 0.5 mmol L^–1, pH 7.1, voltage –20 kV) using direct UV detection at 191 and 254 nm. With this CE method all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all three complexing agents could be detected in less than 4 min. Linear calibration plots were obtained for CuDTPA, CuEDTA and CuNTA; limits of detection were 0.03 mmol L^–1 for all complexing agents and recoveries for all tested samples were within the range 104±7%. Results obtained from dishwashing detergent samples were found to be reliable and comparable with those from HPLC (R²=0.989) and UV–Vis (R²=0.985) methods.     

Analysis of EDTA and DTPA

In this paper, analytical techniques for the determination of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are reviewed. These compounds, especially EDTA, are used as metal chelating agents in several industries. As they are likely to be poorly degraded in waste water treatment plants, significant amounts of EDTA and DTPA are released into natural waters. The overview consists of comparing chromatographic, electrochemical, spectrophotometric, titrimetric and atomic absorption methods and their applicability to the determination of EDTA and DTPA in different matrices.     

Studies of the oxidation of iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) with lead dioxide suspension in nitric acid

The stoichiometry of the oxidation of IDA or NTA with lead dioxide suspension was studied by polarographic measurement and by derivative polarographic titration. One mole and two moles of Pb(IV) are reduced per mole of IDA and NTA respectively, with moderate speed at room temperature in nitric acid solutions. One mole each of carbon dioxide, formaldehyde and glycine are produced from the oxidation of 1 mole of IDA, and two moles of carbon dioxide, two moles of formaldehyde and one mole of glycine from 1 mole of NTA. The overall reaction in each case may be written as follows: Pb(IV) + IDA + H₂O → Pb(II) + CO₂ + HCHO + H₂NCH₂COOH + 2H⁺ 2Pb(IV) + NTA + 2H₂O → 2Pb(II) + 2CO₂ + 2HCHO + H₂NCH₂COOH + 4H⁺     

Evaluation of lanthanum and praseodymium chelates of DTPA,CDTA, EDTA,and NTA as groundwater tracers

The chemical stability of various chelates of La and Pr, as they were carried by water through a large soil column, were evaluated. The purpose of this work was to identify potential radioactive or neutron activatable groundwater tracers. This work established that of the chelates tested, Pr-DTPA followed by La-DTPA were the most stable and thus suitable for testing as groundwater tracers.     

Rapid and sensitive determination of ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid in water samples by ion-pair reversed-phase liquid chromatography--electrospray tandem mass spectrometry

A new method is presented for the quantitative determination of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) from aqueous samples without an enrichment step. It consist of the formation of the Fe(III) complexes of EDTA and DTPA, liquid-chromatography with a volatile ion-pairing agent and determination by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Limits of quantification (LOQ) of 1.0 and 0.6 microgL(-1) for EDTA and DTPA were obtained, allowing the direct injection of most aqueous environmental samples without any preceding enrichment. With a more recent mass spectrometer, the LOQ could be further decreased by almost one order of magnitude. Parallel analysis of real samples by a standardized method employing enrichment, derivatization and GC-MS analysis yielded comparable results. The method was applied to the determination of both complexing agents in several wastewater, surface water and drinking water samples, showing that EDTA is an omnipresent contaminant in partially closed water cycles.     

Investigation of the usefulness of NTA, EDTA and DTPA in separation of some platinum metals on cellulose exchangers

The possibility of using NTA, EDTA and DTPA as complexing agents for separation of some platinum group ions on cellulose ion-exchangers has been investigated. The greatest differences in the affinities of Pd(II) and Pt(IV) toward the cellulose ion-exchangers are obtained in the presence of DPTA, Cellex D (as ion-exchanger) in hydroxide form. The column separation of Pd(II) from Pt(IV), Rh(III) from Pd(II) and of a Rh(III)Pd(II)Pt(IV) mixture can be achieved with DPTA and chloride solutions. The method can be for determination of the components of RhPdPt alloys.     

Phenolic aldehydes and aldoximes as indicators for direct titration of ferric ions with diethylenetriaminepentaacetic acid (DTPA)

Summary Fifteen phenolic aldehydes and aldoximes have been investigated as indicators for the direct titration of iron(III) ions with diethylene triaminepentaacetic acid. Six substances are found to be excellent indicators which permit direct titration of iron(III) with DTPA even at pH 1.0. Microtitrations are feasible with these indicators, the minimum titratable amount being 56g/ml. The process is very selective and can be applied to the analysis of ores and drugs containing iron.

---

Pbenolische Aldehyde und deren Oxime als Indikatoren für die direkte Titration von Eisen(III) mit Diethylentriaminpentaessigsäure (DTPA)

Zusammenfassung Sechs phenolische Aldehyde bzw. deren Oxime bewährten sich als ausgezeichnete Indikatoren für die direkte Titration von Eisen (III) mit DTPA bei pH 1,0. Die geringste titrierbare Menge beträgt 56g/ml. Die Reaktion ist sehr selektiv und eignet sich für die Analyse von Erzen und eisenhältigen Drogen.

     

Influence ofpH and concentration of complexing agents on fluorescence of europium (III) ethylenediaminetetraacetic acid and europium (III) nitrilotriacetic acid complexes in aqueous solutions

The fluorescence of aqueous solutions of Eu(III) complexes withEDTA andNTA has been investigated. Intensities of the fluorescence bands have been measured as a function of complexone concentrations in the solutions and thepH. The results are interpreted in terms of the different forms of Eu(III) complexes and their relative stabilities.

---

Einfluß vonpH und Konzentration der Komplexbildner auf die Fluoreszenz der Komplexe des Europium (III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure in wäßrigen Lösungen

Zusammenfassung Die Fluoreszenz von wäßrigen Lösungen der Komplexe des Europium(III) mit Ethylendiamintetraessigsäure und Nitrilotriessigsäure wurde untersucht. Die Intensitäten der Fluoreszenzbanden in Abhängigkeit vonpH und Konzentration der Komplexbildner wurden auf der Basis vorkommender Komplexgeometrien und deren Stabilitäten interpretiert.

     

Nucleation of calcium carbonate in presence of citric acid, DTPA, EDTA and pyromellitic acid

The influence of four calcium complexing additives, i.e., citric acid (CIT), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and pyromellitic acid (PMA), and their concentration on the induction time of calcium carbonate nucleation has been studied. The experiments were performed by rapidly mixing a sodium carbonate solution and a calcium chloride solution of various concentrations. The induction time was obtained by recording the white light absorption of the solution. Chemical speciation was used to estimate the initial thermodynamic driving force of each experiment. The induction time was found to increase with additive concentration. The effect varies from one additive to another. CIT causes the greatest increase in induction time and PMA the least. Using classical nucleation theory the experimental data were evaluated in terms of the interfacial energy. In pure water a value of 37.8 mJ m(-2) was obtained, showing good agreement with other works. CIT, DTPA and EDTA caused a notable increase of the interfacial energy at a concentration of 0.5 mmol l(-1). PMA does not appear to have any effect at all on the interfacial energy. Different mechanisms for the influence of the additives on the measured induction time and on the estimated interfacial energy are discussed.     

Synthesis and properties of superconductors prepared from ethylenediaminetetraacetic acid (EDTA)-ethylenediamine (ED) polyamide YBC chelate

Single-phase Y₁Ba₂Cu₃O_7-x has been synthesized by a polymer-metal chelate precursor technique. Ethylenediaminetetraacetic acid (EDTA)-ethylenediamine (ED) polyamide was used as chelating polymer for Y, Ba, and Cu. The titration curves of the polymer in the absence and presence of each metal ion showed the chelate formations. The polymer was dissolved in water and the metal nitrates of Y, Ba, and Cu (1:2:3 in mole ratio) were stoichiometrically added to form a homogeneous molecular complex. The clear polymermetal chealate film was obtained by removal of the solvent without phase separation. This precursor was dried, calcined, and sintered to develop the superconducting (1,2,3) phase. The 1,2,3 phase produced was found to be pure according to x-ray diffraction pattern and it possessed good superconducting properties, i.e., the onset of superconductivity was seen at 90.0 K and the resistance rapidly decreased with decreasing temperature, reaching substantially zero at 88.6 K. Scanning electron microscope (SEM) and face and point analyses by electron probe microanalysis (EPMA) showed that Y, Ba, and Cu elements were uniformly dispersed at least micron order. © 1994 John Wiley & Sons, Inc.     

Electron transfer reaction in the chromium(VI)-manganese(II) system in the presence of ethylenediaminetetraacetic acid (EDTA)

Upon addition of Cr ^VI to a solution of ethylenediaminetetraacetic acid (EDTA) and Mn ^II, a transient species appears which has an absorption maximum at 500 nm. Kinetic studies of the outer-sphere oxidation of the Mn ^II-EDTA complex with the Cr ^VI-EDTA complex have been investigated by visible spectrophotometry at 25 °C. The formation of a transient species has been characterized spectrophotometrically and the encounter complex formation constants have been determined (K_OS = 1.75 × 10² and 1.66 × 10³ mol^-2 dm⁶ for [EDTA] and [Mn^II] variations, respectively). The effect of total [EDTA], [Mn^II], [Cr ^VI] and [HClO₄] on the rate of the reaction was determined. On addition of HClO₄, there is a decrease in the rate constants. The reaction product is the Cr^III-EDTA complex with λ_max = 400 and 550 nm. On the basis of the various observations and product characterization a most plausible outer-sphere mechanism has been envisaged.