Determination Of Nickel In Water Research Articles

Development a simple and sensitive method for determination low trace of nickel by local surface plasmon resonance of citrate capped silver nanoparticles

Nickel is a toxic transition metal which can create serious problems in health of humans and wildlife. Thus determination of nickel in environmental samples like waters is important and inevitable. In this research a simple and sensitive method for determination of nickel in water was described based on aggregation of citrate capped silver nanoparticles. Silver nanoparticles were prepared by reduction of silver nitrate with sodium borohydride. Cefixime was as chelating agent in the assay and when nickel was added to the mixture of citrate capped silver nanoparticles and cefixime, color of citrate capped silver nanoparticles changed from light yellow to red that depend on Ni2+ concentration. As a result of aggregation, local surface plasmon resonance (LSPR) band of silver nanoparticles around 395 nm decreased and a new peak appeared in 550 nm. Control experiments with 10 other ions carried out and did not a distinct change in color or spectrum. Under optimized conditions, linear relationship between Ni2+ concentrations and the absorbance ratio of A550/A395 and limit of detection were found in the range of 2.70 µmol L-1 to 17.10 µmol L-1 and 0.80 µmol L-1, respectively. The method was applied in tap and well waters that indicate the colorimetric method has acceptable accuracy and good stability.

Experimental Design Optimization of Supramolecular Dispersive Liquid–Liquid Microextraction of Nickel and its Spectrophotometric Determination

A supramolecular dispersive liquid−liquid microextraction method based on the solidification of the floating organic drop (SM-DLLME-SFOD) combined with spectrophotometry was developed for the separation, preconcentration, and determination of trace amounts of nickel from aqueous samples. The method is based on the extraction of the hydrophobic complex of nickel with α-furildioxime in the coacervates made up of undecanol reverse micelles in a water-tetrahydrofuran mixture. The parameters affecting the extraction of nickel were screened by fractional factorial design with central points. Effective experimental parameters were optimized using central composite design. Under the optimized conditions, the calibration graph was linear for nickel in the concentration range of 3–85 µg/L with a determination coefficient of 0.9992. The limit of detection and the enhancement factor of the method were 0.4 µg/L and 147, respectively. The method was successfully applied to the determination of nickel in water and vegetable samples.

SPECTROPHOTOMETRIC RESEARCH INTO INTERACTION NICKEL (II) WITH 1- (2- PYRIDYLAZO) -2- HYDROXY -4-MERCAPTOFENOL AND AMINOPHENOLS

The complexation reaction of nickel with 1-(2-pyridylazo)-2- hydroxy-4-mercaptophenol (PAGMP) in the presence of aminophenols (AP) was studied by spectrophotometric methods. Out of aminophenols there were used 2-(N,N-dimethylaminomethyl)-4-methylphenol and 2-(N, N-dimethylaminomethyl)-4- chlorophenol. We revealed optimum conditions for formation and extraction of differently ligand compounds and determined proportions of components in the complexes. It found that the complexes were formed in a weakly acidic environment (pH 3.5-6.5). The maximum in the light absorption spectrum is observed at λ=620-650 nm. The molar coefficient of light absorption is ε=(2.3-2.5)×104 . The optimal condition for the formation and extraction of these compounds is the concentration (1.2-1.5)×10-3 M PAGMP and (2.4- 2.6)×10-3 M AP. The maximum optical density is obtained within 15 minutes. Nickel МLC extracts with PAGMP and AF are subject to Beer's law at concentrations of 0.5–18 μg/ml. Proceeding from the results obtained, the photometric methods for the determination of nickel in water and soil were developed.

In-syringe solvent-assisted dispersive solid phase extraction followed by flame atomic absorption spectrometry for determination of nickel in water and food samples

This study presents a new in-syringe solvent-assisted dispersive solid phase extraction (ISSADSPE) method for determination of nickel ions in water and food. The method involved dispersion of a few milligrams of sorbent in the sample solution inside the barrel of a syringe through application of a disperser solvent. In less than 1 min, the extraction equilibrium was achieved due to dispersion of the sorbent and high mass transfer rate. Afterwards, syringe membrane was employed to separate the dispersed sorbent from the solution. Then the ethanol was withdrawn by syringe membrane to dissolve the analyte-enriched sorbent. Flame atomic absorption spectroscopy was applied to assess the obtained extract. Effective factors such as the sorbent nature and amount, sample volume, pH, ligand concentration, type and volume of disperser solvent and eluent, ionic strength and extraction time were evaluated and optimized to improve the extraction efficiency. Under optimized conditions (pH = 8.0, ligand concentration = 2.0 × 10−4, sorbent = 10 mg of benzophenone, disperser solvent 500 μL of ethanol), the limit of detection and quantification were found to be 0.7 μg L−1 and 2.0 μg L−1, respectively. The calibration curve kept its linearity from 2 to150 μg L−1, with the square correlation coefficient of 0.997. The relative standard deviation was measured as 2.5% while the enrichment factor was assessed as 50. The proposed method was successfully applied for determination of nickel in environmental water, spinach and celery samples, with recovery range of 97–101%.

Determination of nickel in water and soil samples at trace levels using photochemical vapor generation-batch type ultrasonication assisted gas liquid separator-atomic absorption spectrometry

A photochemical vapor generation system with sonication assisted batch type gas-liquid separator was optimized to improve the sensitivity, precision and accuracy of nickel determination by atomic absorbance spectrometry. The inefficient nebulizer sample introduction unit of the flame unit was replaced by a UV assisted vapor generator, and atomization of the generated volatile species was achieved with a quartz tube atomizer. Parameters optimized included organic acid type and concentration, UV irradiation period, sonication period, carrier gas flow rate and atomizer temperature. Recovery studies were performed to determine the method's applicability to real samples, and interference studies were done to ascertain possible effects of the matrix on the analyte. The limits of detection and quantification were found to be 9.5μgL−1 and 31.7μgL−1, respectively. The low relative standard deviation indicated high precision, and experimented results of a certified reference material conformed to the certified value, validating the method's accuracy. Percent recoveries recorded were between 95% and 104% and the interferents tested showed different effects on the absorbance signals of nickel.

Extraction and spectrophotometric determination of nickel in water, alloys and edible oil samples

An extraction-spectrophotometric method has been developed for determination of nickel using N'-(2-hydroxybenzylidene)-3-(4-o-tolylpiperazin-1-yl) propanehydrazide ( HTP ) as the new extractant. The reagent reacts with nickel (II) at pH = 9.0 and form a 1:1 yellow color complex, which is extracted into chloroform solvent. The complex showed maximum absorption wavelength at 382 nm. Beer’s law is obeyed in the concentration range of 1.17-12.91 μg.mL -1 with apparent molar absorptivity (0.72 x 10 4 L mol -1 cm -1 ) and Sandell’s sensitivity (0.008 μg/cm 2 /0.001 absorbance units). The tolerance limit of various foreign ions was investigated. The developed method was successfully applied for the determination of Nickel (II) in real water samples, alloy samples and Edible oil samples.

Lead Film Electrode Prepared with the Use of a Reversibly Deposited Mediator Metal in Adsorptive Stripping Voltammetry of Nickel

AbstractThe paper presents the first report on application of a “hybrid” lead film electrode for the adsorptive stripping voltammetric determination of Ni(II) in the presence of nioxime as a complexing agent. The strategy to create a “hybrid” electrode is based on the combination of ex situ and in situ plating methods and the use of a reversibly deposited mediator metal (Zn) for the lead film formation. The surface morphology of a new sensor was characterized by atomic force microscopy. The detection limit for Ni(II) obtained at 120 s of accumulation time was 3.9×10−11 mol L−1. The proposed method was validated for the determination of nickel in water certified reference materials with good results.

Determination of Nickel in Water, Food, and Biological Samples by Electrothermal Atomic Absorption Spectrometry After Preconcentration on Modified Carbon Nanotubes

A new and sensitive SPE method using modified carbon nanotubes for extraction and preconcentration, and electrothermal atomic absorption spectrometric determination of nickel (Ni) in real samples at ng/L levels was investigated. First, multiwalled carbon nanotubes were oxidized with concentrated HNO3, then modified with 2-(5-bormo-2-pyridylazo)-5-diethylaminophenol reagent. The adsorption was achieved quantitatively on a modified carbon nanotubes column in a pH range of 6.5 to 8.5; the adsorbed Ni(II) ions were then desorbed by passing 5.0 mL of 1 M HNO3. The effects of analytical parameters, including pH of the solution, eluent type and volume, sample volume, flow rate of the eluent, and matrix ions, were investigated for optimization of the presented procedure. The enrichment factor was 180, and the LOD for Ni was 4.9 ng/L. The method was applied to the determination of Ni in water, food, and biological samples, and reproducible results were obtained.

Preparation of biomorphic porous calcium titanate and its application for preconcentration of nickel in water and food samples

Biomorphic porous nanocrystalline-calcium titanate (SPCTO) was successfully prepared using the sol–gel method and with sorghum straw as the template. Characterization was conducted through XRD, SEM and FTIR. The ability of SPCTO to adsorb nickel ion in water was assessed. Elution and regeneration conditions, as well as the thermodynamics and kinetics of nickel adsorption, were also investigated. The result showed that the sorbent by the sol–gel template method was porous and has a perovskite structure with an average particle diameter of 26nm. The nickel ion could be quantitatively retained at a pH value range of 4–8, but the adsorbed nickel ion could be completely eluted using 2molL−1 HNO3. The adsorption capacity of SPCTO for nickel was found to be 51.814mgg−1 and the adsorption behavior followed a Langmuir adsorption isotherm and a pseudo-second-order kinetic model. The enthalpy change (ΔH) of the adsorption process was 33.520kJmol−1. At various temperatures, Gibbs free energy changes (ΔG) were negative, and entropy changes (ΔS) were positive. The activation energy (Ea) was 25.291kJmol−1 for the adsorption. These results demonstrate that the adsorption was an endothermic and spontaneous physical process. This same method has been successfully applied in the preconcentration and determination of nickel in water and food samples with good results.

Dispersive Liquid–Liquid Microextraction for Preconcentration and Determination of Nickel in Water

AbstractA method for the determination of nickel in water was developed. The procedure involves preconcentration of nickel by using dispersive liquid–liquid microextraction. The Ni(II) ions were extracted in chloroform in the form of complex with the reagent 2‐(2′‐benzothiazolylazo)‐p‐cresol. Ethanol was used as the disperser solvent. After injection of the extracting mixture in a solution of nickel, a cloudy mixture was observed. A quick centrifugation induces phase separation and thus the settling of rich phase. The nickel content in the rich phase is measured by flame atomic absorption spectrometry. Under optimal conditions, the limit of detection and quantification obtained were 1.4 and 4.7 µg L−1, respectively. Some parameters used to characterize preconcentration systems, such as enrichment factor and consumption index were calculated and resulted in 29 and 0.34 mL, respectively. After optimization of variables and determination of analytical characteristics, the method was used for the analysis of certified reference materials (BCR‐713: wastewater, effluent and BCR‐414: plankton) and real water samples.

Study of the solid phase extraction and spectrophotometric determination of nickel using 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione in environmental samples

A rapid, sensitive and selective method for the determination of nickel based on the rapid reaction of nickel(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Ni(II)–CPAHPD complex with C18 membrane disks has been developed. In the presence of pH 6.8 buffer solution and cetylpyridinium bromide (CPB) medium, CPAHPD reacts with nickel to form a red complex of a molar ratio of 1:1 (nickel to CPAHPD). This complex was enriched by solid phase extraction (SPE) with C18 membrane disks. An enrichment factor of 100 was obtained by elution of the complex from the disks with the minimal amount of isopentyl alcohol. The molar absorptivity and Sandell sensitivity of the complex was 3.11 × 105 L mol−1 cm−1 and 0.0189 ng cm−2, respectively at 549 nm in the measured solution. Beer's law was obeyed in the range of 0.01–0.37 μg mL−1, while that obtained by Ringbom plot was in the range of 0.025–0.35 μg mL−1. The detection and quantification limits were calculated and found to be 0.003 and 0.01 μg mL−1. The proposed method was applied to the determination of nickel in water, food, biological and soil samples with good results.

Study on Solid Phase Extraction and Spectrophotometric Determination of Nickel in Waters and Biological Samples

A sensitive, selective and rapid method for the determination of nickel based on the rapid reaction of nickel(II) with QADMAA and the solid phase extraction of the Ni(II)-QADMAA chelate with <TEX>$C_{18}$</TEX> membrane disks has been developed. In the presence of pH 6.0 buffer solution and sodium dodecyl sulfonate (SDS) medium, QADMAA reacts with nickel to form a violet complex of a molar ratio of 1 : 2 (nickel to QADMAA). This chelate was enriched by solid phase extraction with <TEX>$C_{18}$</TEX> membrane disks. An enrichment factor of 50 was obtained by elution of the chelates form the disks with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate was <TEX>$1.32{\times}10^5L\;mol^{-1}cm^{- 1}$</TEX> at 590 nm in the measured solution. Beer's law was obeyed in the range of 0.01-0.6 <TEX>${\mu}$</TEX>g/mL. This method was applied to the determination of nickel in water and biological samples with good results.

Solid-phase spectrophotometric determination of nickel in water and vegetable samples at sub-μg l −1 level with o-carboxylphenyldiazoaminoazobenzene loaded XAD-4

A highly sensitive and selective solid-phase spectrophotometric method for the determination of sub-μg l −1 level nickel(II) is described. Nickel(II) was sorbed on a styrene-divinylbenzene-type resin Amberlite XAD-4 as a Ni(II)– o-carboxylphenyldiazoaminoazobenzene ( o-CDAA) complex. At pH 9.0, resin phase absorbances at 588 and 800 nm were measured directly with an apparent molar absorptivity of 2.95×10 7 g mol −1 cm −1. The linear range of the determination was 1.2–41 μg g −1 resin. The detection limit and the quantification limit were found to be 0.24 and 0.76 μg g −1 resin, respectively. The relative standard deviation of 10 replicate determinations of 1.0 μg nickel(II) in 100 ml sample was of 1.5%. The tolerance limit of coexistent ions was also investigated. Most of them are in tolerable amount. For practical analyses, 1 ml acetylacetone used can eliminate the interferences caused by Cu and Fe. The procedure was validated by analysis a certified water reference material (GBW 08618 Beijing, China) and a tomato leaf certified reference material (GBW 08402 Beijing, China) with the results in agreement with the certified values. The method was applied to the determination of nickel(II) in water and vegetable samples with satisfactory results.

Determination of nickel in water by electrothermal atomic absorption spectrometry with preconcentration on a tungsten foil

A preconcentration method for nickel in waters involving adsorption on tungsten foil, followed by electrothermal atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer is described. The most suitable pH for nickel adsorption was 5 and the optimum immersion time was 2 min. Severe interferences from co-existing elements (Al, Ca, Cu, Fe, K, Mg, Na, Pb and Zn) on the Ni AA signal were observed. Under optimal conditions, the preconcentration of nickel on W foil could eliminate interferences from these elements. The detection limit of nickel by preconcentration-ETAAS was 0.1 ng/ml (3S/N). The method with preconcentration on tungsten foil was applied to the determination of nickel in river water. The recovery of spiked nickel was 93–102%. The tungsten foil preconcentration method is sensitive, simple, and convenient. This adsorption method can be utilized inin situ-sampling of ultra-trace nickel in environmental samples (water). Furthermore, after sampling it is easy to carry and store the W-foil without contamination for long time.

Determination of nickel in water by chemiluminescence

The acetone chemiluminescence determination of nickel in water was investigated. Optimization data for the determination of Ni2+ and interference data for over 20 species are provided. The limit of detection for Ni2+ by this method is 2.5 ng ml-1, and the linear dynamic range is from 10 ng ml-1 to 1 microgram ml-1. The application of the method to the determination of Ni2+ in river and waste waters is discussed.

A method for the determination of nickel in water and serum by flameless atomic absorption spectrophotometry

A method for the determination of nickel in water and serum by flameless atomic absorption spectrophotometry