Photothermal Deflection Spectroscopy for Ultra Trace Analysis of Cobalt and Copper Ions

Abstract

Photothermal deflection spectroscopy (PDS) is applied for the absolute determination at room temperature of ultra trace concentration of cobalt and copper ions in aqueous solution. The samples have been prepared by percolating 2 liters of solution prepared from Merck Titrisol Standards in 200 mg Merck-I cationic exchange resin. With the present experimental conditions the detection limit is 20 ppb and 200 ppb for copper and cobalt ions respectively within an overall accuracy of 5%. The response of the spectrometer has been calibrated using ICP technique.     

Fluorescence Reaction of 5- (p-Methoxyphenylazo)-8-(p-tolylsulfonamido)quinoline with Cobalt(II) and Its Analytical Application

Abstract

5-(p-Methoxyphenylazo)-8-(p-tolylsulfonamido) quinoline(MTAQ) has been synthesized. The product was checked by IR, theroograviae-try, NMR and elemental analysis. A highly sensitive spectrofluorim-etric method has been developed for the determination of cobalt(II) based on the formation of a complex with MTAQ in slightly basic medium aqueous solution and In the presence of nonionic surfactant, tween-80. The complex shows two excitation maxima at 304 nm and 338 nm, its emission maximum is centred at 402 nm. The fluorescence intensity is proportional to cobalt(II) concentration in the range of 0-85 ppb. The method has good selectivity and has been applied to the direct fluorimetric determination of trace cobalt(II) in pig's liver, Dianchi shrimp and celery.     

The Spectrophotometric Determination of Nickel and Cobalt in Mixtures with Picolinaldehyde 4-Phenyl-3-Thiosemicarbazone

Abstract

The properties of nickel complex of picolinaldehyde 4-pheny1-3-thiosanicarbazone are described. The optimal conditions for a selective and sensitive spectrophotometric determination of nickel are discussed, A photometric method for the determination of traces of cobalt(II) and nickel(II) ions in mixtures has also been developed.     

Room Temperature Phosphorescence Optosensor for Terbium

Abstract

A solid surface room temperature phosphorescence optosensing method has been developed for the determination of terbium(III) based on the adsorption of its binary complex with 1,4-bis (l'-phenyl-3′-methyl-5′-pyrazolone-4′-) butanedione-(1,4) (BPMPBD) onto the hydrogen form of a strong cation exchange resin packed in a flow cell in an aqueous flow system. The phosphorescence intensity is a linear function of the concentration of terbium in the range of 8x10^?9 M-6x10^?7 M, and the detection limit is 3x10^?9 M terbium. The response mechanism was also studied. The present optosensor has been used for the determination of trace amounts of terbium in synthetic samples with satisfactory results.     

New Analytical Applications for Sodium Diethyldithiocarbamate

Abstract

The electrochemical behavior of sodium diethyldithiocarbamate has been studied. A method has been developed to determine trace amounts of the reagent by preparatory electrolysis at a suitable potential which causes the sparingly soluble electrochemical product to precipitate on a small graphite electrode. The inverse polarogram gives a current which can be evaluated quantitatively, produced by the re-dissolving of the film on the electrode. Sodium diethyldithiocarbamate can also be used for electrochemically concentrating cobalt in the form of a sparingly soluble compound of Co(III) by measuring the current required to reduce (re-dissolve) the compound. The electrochemical oxidation reaction of sodium diethyldithiocarbamate to give insoluble films could be used for indirect determination of the metal ions which interact with the reagent.     

Flame Atomic Absorption Spectrometric Determination of Cu(II), Co(II), Cd(II), Fe(III) and Mn(II) in Ammonium Salts and Industrial Fertilizers after PrEconcentration/Separation on Diaion HP-20

A sensitive and simple separation-enrichment technique for the determination of trace amounts of Cu(II), Co(II), Cd(II), Fe(III) and Mn(II) was described. Metal ions were complexed with 1-nitroso-2-naphthol at pH 9. Following solid-phase extraction on Diaion HP-20 resin, metals were determined by flame atomic absorption spectrometry. The effect of the matrix ions were investigated. The recoveries of metal ions were greater than 95%. The detection limits of the analyte ions ( k = 3, N = 21) were varying 0.18 µg/l for Cd(II) to 0.44 µg/l for Fe(III). The method was applied to a stream sediment standard reference material (GBW7309), some ammonium salts and industrial fertilizer samples for the determination of copper, cobalt, cadmium, iron and manganese. The relative standard deviations (RSD) of the determinations for analyte ions at µg/g levels varied from 1 to 10%.     

Simultaneous Trace Determination of Nickel and Cobalt in Natural Waters by Differential Pulse Polarography

Abstract

A differential pulse polarographic method has been developed for the simultaneous low level determination of nickel and cobalt in the presence of furildioxime in natural waters. The nature of the electrode processes was studied with cyclic voltammetry. Limits of determination of 0.4 μg/L and 0.15 μg/L were achieved for nickel and cobalt respectively     

Preconcentration of cobalt using Amberlyst 36 as a solid-phase extractor and its determination in various environmental samples by flame atomic absorption spectrometry

A new and simple column-solid-phase extraction method has been developed to separate and preconcentrate trace cobalt in water and soil prior to its determination by flame atomic absorption spectrometry (FAAS). Different factors such as pH of sample solution, sample volume, amount of resin, flow rate of aqueous solution, volume and concentration of eluent, and matrix effects for preconcentration were optimized. Under optimized experimentally established conditions, an analytical detection limit of 0.44?µg?L^?1, precision (RSD) of 1.9%, enrichment factor of 200, and capacity of resin of 82?mg?g^?1 were obtained. The method was applied for cobalt determination by FAAS in tap water, natural drinking water, soil, and roadside dust samples. The accuracy of the method is confirmed by analysing standard reference material (Montana Soil, SRM 2711).     

Simultaneous Determination of Nickel and cobalt in Manganese Sulphate Electrolyte by DMGH2-Sensitized Differential Pulse Polarography

Abstract

A method is described for the simultaneous determination of nickel and cobalt in manganese sulphate electrolyte by the dimethylglyoxime (DMGH₂) sensitized differential pulse polarography. The high manganese sulphate background (1.2M) in the concentrated process plant electrolyte interferes only with the nickel determination and precludes its direct determination. A 50% v/v dilution and an excessive amount (2 × 10^?3M) of the chelating agent are required at pH7.7 for the reliable determination of both elements. Under these conditions, the linear concentration ranges are 0-110 μg/1 for nickel and 0-140 μg/1 for cobalt. The minimum detectable amounts above the levels present in the process plant electrolyte are 2 μg/1 and 1 μg/1 for both elements, respectively. The relative standard deviations for all measurements are between 1 and 3%.     

Determination of trace amounts of cobalt in water by solid-phase spectrophotometry after preconcentration on a nitroso R salt chelating resin

A sensitive method for the determination of microamounts of cobalt by ion-exchanger spectrophotometry has been developed. The chromogenic agent, Nitroso-R-Salt (NRS), was loaded on an anionic-exchange resin (Amberlite CG-400). The absorbance of the NRS-cobalt complex on the chelating resin was measured at 508 nm. The best conditions for the preconcentration of cobalt on the resin before the spectrophotometric determination were a pH value of 6, temperature of 80 °C, and heating times of 45 or 90 min for 50 and 400 ml of sample, respectively. The detection limits were 27 ng/ml (50-ml samples) and 1.8 ng/ml (400-ml samples). Interference by other metals was investigated. The method is useful for determination of cobalt in natural waters.     

Determination of Uranium in Natural Waters by Solid Phase Spectrometry

Abstract

A microdetermination method (at the μg1^?1 level) for uranium has been developed, based on Solid-Phase Spectrophotometry (SPS). The uranium reacts with pyridylazo-resorcinol in the presence of fluoride to form a 1:1:1 red ternary complex, which is fixed on an anion-exchange resin. The resin absorbance is measured directly, and allows the determination of uranium in the range of 1–10μg1^?1, with an RSD of 4%. The method has been applied to the determination of U(VI) in natural waters from wells located near the deposits of industrial wastes from a uranium mineral plant in Andujar (Spain).     

Preparation and analytical properties of a chelating resin containing phenylalanine groups

A polystyrene-based macroreticular resin containing phenylalanine groups has been prepared and its analytical properties have been investigated and compared with Dowex A-1. The phenylalanine resin shows high selectivity for mercury(II) and copper(II) in the pH region 2-3. The sorption behaviour of copper has been examined in detail, with the intention of using the resin analytically. The important characteristics of the resin are fast equilibration, high selectivity and small volume change between its hydrogen form and metal forms. These enable it to be applied for the rapid concentration of trace amounts of copper in the presence of large amounts of diverse metals. It may be used for the determination of copper in sea-water and the separation of copper/cobalt and copper/nickel.     

Synthesis and Application of New Resin Functionalized by Brilliant Green for Spectrophotometric Determination of Mercury in Environmental Samples

Abstract

A new chelating resin was prepared by coupling Amberlite XAD-4 with brilliant green through an azo spacer, and it has been used for preconcentration and separation of mercury(II) in environmental samples prior to its determination by spectrophotometry. The sorption capacity of functionalized resin is 4.12 mg g^?1. Spectrophotometric determination of Hg(II), free from the interference of almost all cations and anions found in the environmental water samples, is a notable advantage of the method. The determination of Hg(II) in wastewater and seawater was carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS).     

Determination of Manganese (II) in Foodstuffs by β-Cyclodextrin Polymer Phase Spectrophotometry with 1-(2-Pyridylazo)-2-naphthol

The chromogenic agent, 1-(2-pyridylazo)-2-naphthol (PAN) was included in g -Cyclodextrin polymer ( g -CDP) and the modified polymer of inclusion of PAN ( g -CDP-PAN) was obtained. Based on the fact that g -CDP-PAN can adsorb Mn (II) in solution to form Mn (II)-PAN complex, a sensitive and selective solid phase spectrophotometric method for the determination of trace amounts of Mn (II) has been developed. The maximum absorbance of Mn (II)-PAN complex in g -CDP was at 514 nm. The working range of the calibration graph was 2-12 w g of Mn (II). The interference of molybdenum, lead, cobalt, chromium, iron, nickel, zinc, tin, cadmium, and copper that form colored species with PAN in the polymer phase was investigated. The method was applied to the determination of Mn (II) in black rice and tea samples. A new method for the determination of trace amounts of manganese by polymer phase spectrophotometry is described. Manganese reacted with 1-(2-pyridylazo)-2-naphthol (PAN) that was included in a g -cyclodextrin polymer. The absorbance of the colored polymer, packed into a 5 mm quartz cell, was determined directly at 514 nm. The proposed method was applied to the determination of manganese in black rice and tea samples.     

Determination of ultra trace amounts of cobalt and nickel in water samples by inductively coupled plasma-optical emission spectrometry after preconcentration on modified C18-silica extraction disks

A highly sensitive and accurate method for preconcentration and determination of ultra trace amounts of cobalt and nickel ions in water samples is proposed. The preconcentration is achieved using C₁₈-silica extraction disks modified with 5-(6-methoxy-2-benzothiazoleazo)-8-aminoquinoline (MBTAQ). The retained ions on the prepared solid phase was eluted with 10 ml of 0.01 M nitric acid and measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). The influence of the type and amount of eluent used, pH, sample and eluent flow rates, amount of MBTAQ and the effect of other ions on extraction efficiency were investigated. The limits of detection of the method were 0.08 and 0.06 μg l^− 1 for cobalt and nickel, respectively, and provide an enrichment factor of 100. The results obtained on 10 successive extractions and elution cycles revealed relative standard deviations of 1.5 and 1.0% for cobalt and nickel, respectively. The proposed method has been applied to the determination of ultra trace amounts of cobalt and nickel ions in natural and synthetic water samples with satisfactory results.     

Indirect AAS Determination of Cationic Surfactants in Waste Effluents and Shampoos

Abstract

An indirect atomic absorption spectro-metric (AAS) method using electrothermal atomization (ETAAS) for the determination of cationic surfactants has been proposed. The method involves ion-pair formation between cationic surfactant and sodium hexanitro-cobaltate(III), extraction of the ion-pair into 1, 2-dichloroethane and determination of cobalt con centration in organic phase by ETAAS and hence indirectly relating to the cationic surfactant concentrations. Surfactants of the anionic and nonionic group do not interfere to a great extent, and matrix inter ferences from many other cations, anions and organics are also not observed. The method has been success fully applied to cationic surfactant determination in waste water and hair rinsers. Relative standard deviation values (RSD) of 3.2% for waste water samples and 4.3% for shampoo were observed in these analyses.     

Spectrophotometry Determination of Cobalt after Extraction of its Ternary Complex with 3-(4-Phenyl-2-Pyridyl)-5,6-Diphenyl-1,2,4-Triazine and Tetraphenylborate into Molten Naphthalene

The reaction of 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PPDT) and tetraphenylborate (TPB) with cobalt (II) has been studied to determine the optimum conditions for the extraction and quantitative spectrophotometry determination of this metal. The ternary complex is extracted into molten naphthalene at pH 3.6–7.4. The solid naphthalene containing the cobalt associated complex is separated by filtration and dissolved in acetonitrile. Beer's law is obeyed in the concentration range 8–140 μg cobalt in 10 ml of acetonitrile solution. The molar absorptivity and sensitivity are 4.2×10³ l·mol^?1·cm^?1 and 0.01408 μg/cm², respectively. The other factors such as pH, amounts of reagents and naphthalene, shaking and standing times, and the effect of diverse ions are studied. The method has been applied to the determination of cobalt in iron steel alloys.     

Determination of ultra trace amounts of cobalt and nickel in water samples by inductively coupled plasma-optical emission spectrometry after preconcentration on modified C18-silica extraction disks

A highly sensitive and accurate method for preconcentration and determination of ultra trace amounts of cobalt and nickel ions in water samples is proposed. The preconcentration is achieved using C₁₈-silica extraction disks modified with 5-(6-methoxy-2-benzothiazoleazo)-8-aminoquinoline (MBTAQ). The retained ions on the prepared solid phase was eluted with 10 ml of 0.01 M nitric acid and measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). The influence of the type and amount of eluent used, pH, sample and eluent flow rates, amount of MBTAQ and the effect of other ions on extraction efficiency were investigated. The limits of detection of the method were 0.08 and 0.06 μg l^− 1 for cobalt and nickel, respectively, and provide an enrichment factor of 100. The results obtained on 10 successive extractions and elution cycles revealed relative standard deviations of 1.5 and 1.0% for cobalt and nickel, respectively. The proposed method has been applied to the determination of ultra trace amounts of cobalt and nickel ions in natural and synthetic water samples with satisfactory results.     

An Improved Solid Phase Spectrophotometry Method for the Determination of Aromatic Esters

Abstract

A method based on Solid Phase Spectrophotometry was developed for the determination of methyl benzoate. Hydroxamic acid formed by the reaction between the above and hydroxylamine, reacts with V(V) and oxalate yielding a violet compound, which is sorbed on an anion-exchange resin. The absorbance of the resin phase at 546 and 750 nm is measured directly. The calibration graph is linear for the 4.8–23 μM concentration range. RSD is shown as 3.7%, with a detection limit of 0.09 mg. 1^?1. This method has been applied to the determination of aromatic esters in brandies.     

Spectrophotometric Determination of Cobalt in Vitamin Preparations,Steel and Iron Using 2-Hydroxy- 1-Naphthaldehyde Guanylhydrazone

Abstract

A new spectrophotometric determination of cobalt with 2-hydroxy-1-naphthaldehyde guanylhydrazone in acid medium is described. The method is developed on the basis of a yellow cobalt (III) complex (molar absorptivity 1.32×10^?4 L.mol^?1.cm^?1 at 416 nm, stoichiometry 2:1). The method was applied to the determination of cobalt in vitamin preparations, steel and high-purity iron.