High performance liquid chromatographic determination of copper(II) and nickel(II) by using solvent extraction and bis(acetylpivalylmethane)ethylenediimine as complexing reagent

The reagent bis(acetylpivalylmethane)ethylenediimine has been examined for the HPLC separation of copper(II), nickel(II), palladium(II) and oxovanadium(IV) chelates on reversed phase HPLC columns (250 x 4 mm) packed with Hypersil ODS, 5 mu and (150 x 3.9 mm) Nova Pak C(18) with guard column. The complexes are eluted with a binary mixture of methanol and water or methanol, acetonitrile and water. Detection is achieved with a UV detector. The solvent extraction procedure is used for the determination of copper and nickel simultaneously at microgram levels, corresponding to ng levels and pg levels respectively, per injection. The method has been applied to the determination of copper and nickel in a coin, nickel-aluminum alloy and water samples.     

High performance liquid chromatographic separation and UV determination of cobalt, copper iron and platinum in pharmaceutical preparations using bis(isovalerylacetone)ethylenediimine as complexing reagent

The reagent bis(isovalerylacetone)ethylenediimine(H₂IVA₂en) has been examined for HPLC separation and UV determination of cobalt, copper, iron and platinum using off-line precolumn derivatization and extraction in chloroform. The complexes of cobalt(II), cobalt(III), iron(II), iron(III) and the reagent have been subsequently separated on a Microsorb C-18 column. The complexes were eluted isocratically using ternary mixtures of methanol/water/acetonitrile. Detection was achieved by UV monitoring. Detection limits for Co(II), Co(III), Fe(II) and Fe(III) were 2.5–5.0 ng/injection, based on 0.5–1.0 g/ml with 5 l/injection. The concentration of cobalt(II) and cobalt(III) in aqueous solution have been determined. The presence of oxovanadium(IV), platinum(II), and nickel(II) did not affect the determinations. The HPLC method developed has been applied to the determination of cobalt, copper, iron and platinum in pharmaceutical preparations at the 30 g/g to 15 mg/g level and the obtained results were compared to those of atomic absorption spectrometry.     

The simultaneous determination of copper and nickel by solvent extraction and gas-liquid chromatography with bis (acetylpivalylmethane) ethylenediimine as reagent

The copper(II), nickel(II) and palladium(II) chelates of the bridged β-ketoamine, bis(acetylpivalylmethane) ethylenediimine, are described. The copper and nickel complexes are readily extracted by cyclohexane at pH 8.0 from aqueous solution. The gas chromatographic separation of the copper and palladium, the nickel and palladium, and the copper and nickel chelates is reported on a silicone gum rubber phase (E-350) supported on Universal B at 285°C. Optimal conditions for the complete separation of copper and nickel are reported; the solvent extraction—gas chromatographic procedures are applied to the determination of the individual metal ions (limit of detection, 1 ng) and to the simultaneous determination of copper and nickel in solution and in alloy samples. A rapid method for the determination of copper in domestic water samples is also described.     

Simultaneous determination of cobalt,copper, iron and vanadium in crude petroleum oils by HPLC

Summary A method has been developed for the simultaneous formation and solvent extraction of cobalt (II), copper (II), iron (II) and vanadium (IV) complexes of bis (acetylpivalylmethane)ethylenediamine (H₂APM₂en) in methyl isobutyl ketone. The complexes are eluted from a reversed phase HPLC column with a mixture of methanol:water:acetonitrile and detection was at 260 nm. The method has been applied to the simultaneous determination of cobalt, copper, iron and vanadium in crude petroleum oils at the ng level.     

High-performance liquid chromatographic determination of uranium using solvent extraction and bis(salicylaldehyde) tetramethylethylenediimine as complexing reagent

The reagent bis(salicylaldehyde)tetramethylethylenediimine has been used for the determination of dioxouranium(VI), based on complexation in aqueous solution at pH 6, followed by extraction in chloroform and HPLC determination on a Hypersil ODS (3 μm) column. The complex was eluted with the ternary mixture methanol-acetonitrile-water (40:30:30, v/v/v), with UV detection at 260 nm. Oxovanadium(IV), iron(III), copper(II), cobalt(II), nickel(II) and palladium(II) were completely separated and did not interfere in the determination of uranium. The linear calibration range and detection limits have been obtained. The method has been applied to the determination of uranium together with copper, iron and nickel in mineral ore samples.     

The simultaneous determination of copper and nickel by liquid-liquid extraction and gas-liquid chromatography with (acetylpivalylmethane)-(trifluoroacetylacetone)ethylenediimine as reagent

The unsymmetrical tetradentate ligand, 1,1,1-trifluoro-1′,1′,1′-trimethyl-4,4′-(ethane-1,2-diyldiimino)bis(pent-3-en-2-one), derived from the condensation of trifluoroacetylacetone and acetylpivalylmethane and trivially named (acetylpivalylmethane)(trifluoroacetylacetone)ethylenediimine has been isolated and its copper(II) and nickel chelates have been prepared. These chelates are readily separated by gas chromatography and a method is proposed for the simultaneous determination of copper and nickel by liquid-liquid extraction of their chelates with the new reagent followed by gas chromatography on a column of OV-1 supported on Gas Chromb Q at 230°C. The method is applied to the determination of the composition of cupro-nickel coinage metal.     

Simultaneous solvent extraction and high-performance liquid chromatographic determination of uranium, iron, nickel and copper in mineral ore samples and phosphate rock residues using N,N′-ethylenebis(salicylaldimine) as complexing reagent

The reagent N,N-ethylenebis(salicylaldimine) (H₂SA₂en) has been examined for precolumn derivatization, followed by solvent extraction in chloroform and HPLC determination of uranium, iron, nickel and copper on a Hypersil ODS 3 μm column. Complexes were eluted isocratically using a ternary mixture of methanol-acetonitrile-water and UV detection was at 260 nm. The detection limit was 12 ng/injection for each of the elements. The method has been applied for the determination of metals in mineral ore samples and phosphate rock residues. The results obtained are compared using atomic absorption.     

Determination of uranium, iron, copper, and nickel from ore samples by MEKC using N,N'-ethylene bis(salicylaldimine) as complexing reagent

An analytical procedure has been developed for the separation of dioxouranium(VI), iron(III), copper(II), nickel(II), cobalt(II), cobalt(III), palladium(II), and thorium(IV) by MEKC using N,N'-ethylene bis(salicylaldimine) (H(2)SA(2)en) as a complexing reagent with total runtime <4.5 min. SDS was used as micellar medium at pH 8 with sodium tetraborate buffer (0.1 M). An uncoated fused-silica capillary with an effective length of 50 cm x 75 microm id was used with an applied voltage of 30 kV with photodiode array detection at 231 nm. Linear calibrations were obtained within 0.111-1000 microg/mL of each element with LODs within 37-325 ng/mL. The developed method was tested for analysis of uranium ore samples indicating its presence within 103-1789 microg/g with RSD within 0.79-1.87%. Likewise copper, nickel, and iron in their combined matrix were also simultaneously determined with RSD 0.4-1.6% (n = 6).     

MEKC determination of vanadium from mineral ore and crude petroleum oil samples using precapillary chelation with bis(salicylaldehyde)tetramethyl‐ethylenediimine

An analytical procedure has been developed for the separation of Cu(II), Ni(II), Co(II), Fe(II), Pd(II), Th(IV), V(IV), and determination of Fe(II), Co(II), Ni(II), and V(IV) by MEKC after chelation with bis(salicylaldehyde)tetramethylethylenediimine (H₂SA₂Ten). Uncoated fused silica capillary was used with an applied voltage of 30 kV with photo‐diode array detection at 228 nm. SDS was added as micellar medium at pH 8.2 with sodium tetraborate buffer (0.1 M). Linear calibrations were established within 0.015–1000 μg/mL of each element with LOD within 5–67 ng/mL. The method was applied for the determination of vanadium from crude oil and ore samples in the range 0.34–2.40 and 114.2–720.7 μg/g with RSD 1.7–3.8 and 0.98–2.30% (n = 3), respectively. Fe, Ni, and Co present in crude oil and ore samples were also determined with RSD 1.3–2.8, 1.1–4.1, and 1.2–3.5% (n = 3), respectively. The results were compared with that of supplier's specifications and atomic absorption spectrometry (AAS). Method was evaluated by standard addition technique.     

Liquid chromatographic determination of vanadium in petroleum oils and mineral ore samples using 2-acetylpyridne-4-phenyl-3-thiosemicarbazone as derivatizing reagent

Liquid chromatographic method has been developed, based on precolumn derivatization of vanadium(V) with 2-acetylpyridine-4-phenyl-3-thiosemicarbazone (APPT). The complex is extracted in chloroform together with palladium(II), tin(II) and iron(III) and eluted and separated completely from Kromasil 100 C-18, 10 μm (25 cm × 4.6 mm i.d.) column with methanol:water:acetonitrile (60:30:10, v/v/v) with a flow rate of 1 ml/min. UV detection was at 260 nm. Linear calibration curve was obtained with 1-12.5 μg/ml vanadium(V) with detection limit of 8 ng/injection (20 μl). A number of metal ions tested did not affect the determination of vanadium. The test mixtures were analyzed for vanadium(IV) and vanadium(V) contents and relative% error was obtained ±1-8%. The method was applied for the determination of vanadium in petroleum oils and mineral ore samples with vanadium contents of 0.32-2.3 and 121.7-717.3 μg/g with R.S.D. of 1.5-4.5 and 0.38-4.7%, respectively. The results correlated with reported values and by atomic absorption spectrophotometry.     

High-performance liquid chromatographic determination of nickel,copper and zinc as their tetraphenylporphine chelates

Nickel(II), copper(II) and zinc(II) ions are extracted from an aqueous solution into carbon tetrachloride as their diethyldithiocarbamate (DDC) chelates. The extract, after removal of the solvent, is treated with meso-tetraphenylporphine (TPP) in benzyl alcohol at 140°C for 60 min. Quantitative conversion of the DDC chelate to the TPP chelate is obtained over the range 0.25–4.5 μg of each metal by use of 3 μgmol of TPP. The reaction mixture is analysed by reversed-phase high-performance liquid chromatography with spectrophotometric detection at 412 nm. Simultaneous determination of Cu and Zn in NBS bovine liver is possible by this procedure.     

Spectrophotometric determination of trace amounts of iron(III) with norfloxacin as complexing reagent

The complexation of iron(III) with norfloxacin in acidic solution at 25 degrees C, at an ionic strength of about 0.3 M and a pH of 3.0 has been studied. The water-soluble complex formed, which exhibits an absorption maximum at 377 nm, was used for the spectrophotometric determination of trace amounts of iron(III). The molar absorptivity was 9.05 x 10(3) I mol-1 cm-1 and the Sandell sensitivity 6.2 ng cm-2 of iron(III) per 0.001 A. The formation constant (Kf) was determined spectrophotometrically and was found to be 4.0 x 10(8) at 25 degrees C. The calibration graph was rectilinear over the range 0.25-12.0 p.p.m. of iron(III) and the regression line equation was A = 0.163c - 0.00042 with a correlation coefficient of 0.9998 (n = 9). Common cations, except cerium (IV), did not interfere with the determination. The results obtained for the determination of iron(III) using the described procedure and the thiocyanate method were compared statistically by means of the Student t-test and no significant difference was found.     

Liquid chromatographic determination of cobalt(II), copper(II) and iron(II) using 2-thiophenaldehyde-4-phenyl-3-thiosemicarbazone as derivatizing reagent

The complexing reagent 2-thiophenaldehyde-4-phenyl-3-thiosemicarbazone (TAPT) was examined for high performance liquid chromatographic (HPLC) separations of cobalt(II), copper(II) and iron(II) or cobalt(II), nickel(II), iron(II), copper(II) and mercury(II) as metal chelates on a Microsorb C-18, 5-mum column (150x4.6 mm i.d.) (Rainin Instruments Woburn, MA, USA). The complexes were eluted isocratically with methanol:acetonitrile:water containing sodium acetate and tetrabutyl ammonium bromide (TBA). UV detection was at 254 nm. The solvent extraction procedure was developed for simultaneous determination of the metals, with detection limits within 0.5-2.5 mug ml(-1) in the final solution. The method was applied for the determination of copper, cobalt and iron in pharmaceutical preparation.     

Spectrophotometric determination of copper, nickel, cobalt, iron and manganese as their pyridine thiocyanates Simultaneous determination in mixtures

Spectrophotometric determinations of copper, nickel, cobalt, iron, and manganese, based on the chloroform extraction of the metal pyridine thiocyanates, have been investigated. Optimum conditions require the pH of the aqueous solution to be in the range about 5–8; tartaric acid is used to prevent precipitation of hydrous oxides. An excess of pyridine must be used because chloroform readily extracts pyridine from the aqueous solution. Results are improved by making the extraction from a solution of high ionic strength (2 or above), which is provided by magnesium nitrate. Perchlorate decreases the absorbance, but the effect is essentially constant over a perchlorate concentration range of 0.8 to 2M. Although the metal pyridine thiocyanates are extracted by benzene, substituted benzenes, and halogenated hydrocarbons, chloroform is superior to other solvents in extraction efficiency and in colour stability of the extracted species. An example is given of the simultaneous determination of copper, nickel, cobalt, and iron in the same solution. Anions that also form metal pyridine compounds must be absent.     

Direct atomic absorption spectrometric determination of copper,nickel and vanadium in coal and petroleum coke

The solid sampling technique is used to determine copper, nickel and vanadium in coals and a petroleum coke. The National Bureau of Standards SRM 1632a, Trace Elements in Coal, and aqueous solutions of the elements were employed as standards. The contents of copper, nickel and vanadium were in the ranges 1–17, 3–130 and 20–140 ppm, respectively.     

Selective detection of volatile nickel,vanadium, and iron porphyrins in crude oils by gas chromatography-atomic emission spectroscopy

This report describes the selective detection of volatile nickel, vanadium, and iron metalloporphyrins in crude oil samples. An atomic emission detector (AED) was used for simultaneous detection of these metals using the Ni 301.2 nm, V 292.4 nm, and Fe 302.1 nm emission lines. Detection limits for these metals range from 0.05 to 5 pg/sec. The presence of volatile forms of these metals in several crude oil samples has been confirmed.     

Simultaneous spectrophotometric determination of copper(II), vanadium(V), and iron(III) using 2-hydroxy-1-naphthaldehyde benzoylhydrazone

A simple and new simultaneous spectrophotometric method is proposed for the analysis of a three-component system containing Cu(II), V(V) and Fe(III) without separation using 2-hydroxy-1-naphthaldehyde benzoylhydrazone (OHNABH). The reagent reacts with all the three metal ions at pH 5, forming soluble colored species in 30% DMF. The physico-chemical characteristics, statistical analysis and application of the method for the analysis of complex materials are reported. The effect of diverse ions and the stoichiometry and stability constants are also studied. This article was submitted by the authors in English.     

Tropoloae as a specific reagent for the determination of vanadium(V)

The blue colour developed on interaction of vanadium(V) with tropolone m 5.5-7.0N acid can be extracted into chloroform. The complex has an absorption maximum at 590 nm. Colour development is instantaneous and the extracted species is stable for 72 hr. Beer's law is followed in the range 1.02-14.25 ppm of vanadium. The molar absorptivity is 4.63 x 10(3)l.mole(-1).cm(-1). Most anions do not interfere. Of the 37 cations examined, only Ti(III), Ru(III), Pt(IV), Ir(IV), Mn(II), Ta(V) and Ce(III) were found to interfere. The interference due to these cations has been removed by masking them with EDTA.     

Simultaneous determination of iron(II) and iron(III) by micellar electrokinetic chromatography using an off-line selective complexing reaction.

A simultaneous determination with UV detection/capillary electrophoresis for Fe(II) and Fe(III) was achieved using a sulfonated bathophenantholine and desfferioxamine B. When the electrophoretic buffer was 60 mmol l(-1) SDS, 10 mmol l(-1) acetic acid (pH 4.0) and 10 mmol l(-1) ascorbic acid and at -10 kV, the iron(II) and iron(III) could not only be completely separated, but also be sensitively determined.     

Vanadium(III) as an analytical reagent: The titrimetric determination of iron, copper, thallium, molybdenum, uranium, vanadium, chromium and manganese

Vanadium(III) solutions can be used in direct titrations of iron(III), copper(II), thallium(III), molybdenum(VI), uranium(VI), vanadium(V), chromium(VI) and manganese(VII) in milligram amounts. The titrations are done at 70-80 degrees for iron(III), copper(II), thallium(III), molybdenum(VI) and at room temperature for vanadium(V), chromium(VI) and manganese(VII). Uranium(VI) is titrated at 70-80 degrees in presence of iron(II). The vanadium(III) solution is prepared by reduction of vanadium(V) to vanadium(IV) with sulphur dioxide, followed by addition of phosphoric acid and reduction with iodide, and is reasonably stable.