Determination Of Trace Nickel Research Articles

Determination of Trace Nickel(II) after the Preliminary Extraction of Complexes with 1-(2-Allylamino-1-Methylethyl)Thiocarbamide

Determination of Trace Nickel(II) after the Preliminary Extraction of Complexes with 1-(2-Allylamino-1-Methylethyl)Thiocarbamide

Trace nickel determination in seawater matrix using combination of dispersive liquid-liquid microextraction and triethylamine-assisted Mg(OH)2 method.

In order to eliminate the effects of seawater matrix on the precise/accurate determination of elements, new and efficient analytical procedure requires. In this study, co-precipitation method based on the triethylamine (TEA)-assisted Mg(OH)2 was performed to eliminate side-effects of seawater medium on the determination with flame atomic absorption spectrometry (FAAS) prior to the preconcentration of nickel by an optimized dispersive liquid-liquid microextraction (DLLME) method. Under the optimum conditions of the presented method, the limit of detection and quantification (LOD, LOQ) values obtained for nickel were found as 16.1 and 53.8μgkg-1, respectively. Seawater samples collected from West Antarctic region were used for real sample applications to check the accuracy and applicability of developed method, and satisfying recovery results (86-97%) were obtained. In addition to this, the digital image-based colorimetric detection system and the UV-Vis system were applied to confirm the applicability of the developed DLLME-FAAS method in other analytical systems.

MoS2–Covalent Organic Framework Composite as a Bifunctional Supporter for the Determination of Trace Nickel by Photochemical Vapor Generation–Microplasma Optical Emission Spectrometry

A microplasma-based optical emission spectrometry (OES) system has emerged as a potential tool for field analysis of heavy metal pollution due to its features of portability and low energy consumption, while the development of an efficient sample introduction approach against matrix interference is crucial to meet the requirements of complex sample analysis. Herein, a MoS2-covalent organic framework (COF) composite serves as a bifunctional supporter for efficient sample separation/enrichment and photochemical vapor generation (PVG) enhancement, thereby achieving highly selective and sensitive detection of heavy metals in environmental water by dielectric barrier discharge (DBD) microplasma-OES. With trace nickel analysis as a model, the MoS2-COF composite with a large specific surface area and a porous structure can not only efficiently separate and enrich nickel ions from a sample matrix through electrostatic interaction and coordination to reduce the interference of coexisting ions but also significantly improve the subsequent PVG efficiency due to the formed heterojunction and more negative reduction potential. Under optimized conditions, a linear range of 0.1-10 μg L-1 along with a detection limit of 0.03 μg L-1 is obtained for nickel. Compared with direct PVG, the tolerance to coexisting ions is greatly enhanced, and the detection limit is also improved by 43-fold. The accuracy and practicability of the present PVG-DBD-OES system are verified by measuring several certified reference materials and real water samples. MoS2-COF as a bifunctional supporter promotes the performance of the PVG-DBD-OES system in terms of anti-interference ability and detection sensitivity, especially for robust and efficient on-site analysis of complex samples.

Determination of Trace Nickel after Complexation with a Schiff Base by Switchable Solvent – Liquid Phase Microextraction (SS-LPME) and Flame Atomic Absorption Spectrometry (FAAS)

The determination of trace metals is very crucial in order to identify their functionalities in the human body and help to protect human health. For this purpose, a sensitive and accurate analytical method was developed to determine nickel at trace levels by flame atomic absorption spectrometry after preconcentration with switchable solvent based liquid phase microextraction. Experimental conditions of the method were systematically optimized to maximize the extraction yield. Nickel was complexed with a Schiff base ligand synthesized from the reaction of 1- naphthylamine and 5-bromosalicylaldehyde to obtain an insoluble and easy to extract compound. Under the optimal conditions of the developed system, analytical figures of merit were determined. The relative standard deviation for the lowest concentration in the dynamic working range was under 11% which demonstrated good precision. The enhancement in detection power recorded by the switchable solvent based liquid phase microextraction-flame atomic absorption spectrophotometry compared the conventional flame atomic absorption on the basis of detection limit was approximately 40-fold. The applicability and accuracy of the developed method were investigated by spiking tap water with nickel and the recoveries were from 91 to 98%.

Micro-spectrophotometric determination of nickel in Gentiana rigescens after switchable hydrophilicity solvent-based ultrasound-assisted liquid phase microextraction

In this work, switchable hydrophilicity solvent-based ultrasound-assisted liquid phase microextraction (SHS-UA-LPME) was combined with micro-volume UV-vis spectrophotometry for the determination of trace nickel in the medicinal plant Gentiana rigescens Franch. ex Hemsl. (G. rigescens) samples for the first time. Micro-volume spectrophotometry has the characteristics of microanalysis, economy and low operation cost, which is feasible to be combined with miniaturized enrichment method. Dipropylamine (DPA) as a switchable solvent completed the extraction during the phase conversion process. It was changed from hydrophobic to hydrophilic under the action of HCl, and then completed phase transition under the action of NaOH. The parameters influencing the extraction efficiency were investigated. Under the optimal conditions, the enhancement factor (EF), the limit of detection (LOD), the limit of quantitation (LOQ) and relative standard deviation (RSD, n = 7) were 28, 0.02 µg/L, 0.067 µg/L and 1.4%, respectively. The established method was applied to the determination of G. rigescens samples collected from the local field with satisfactory results.

A new microextraction method for trace nickel determination in green tea samples: Solventless dispersion based dispersive liquid-liquid microextraction combined with slotted quartz tube- flame atomic absorption spectrophotometry

In this study, a simple and novel analytical approach was developed in order to determine nickel at trace levels. For this purpose, a dispersive liquid-liquid microextraction (DLLME) method based on solventless dispersion of extraction solvent was developed to separate/preconcentrate nickel from aqueous solution. Combination of the DLLME method with slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS) lowered the analyte’s detection limit. In the DLLME method, the extraction solvent was dispersed into aqueous solution by generating fine droplets through air assisted spraying in order to reduce organic solvent consumption and avoid relative error by reducing multiple operation steps. Complexation of nickel(II) was done by using a Schiff Base synthesized from the reaction between 3,5- dibromosalicylaldehyde and 2-aminophenol. All experimental parameters were optimized comprehensively by the step-by-step approach in order to determine optimum conditions to get maximum absorbance values. Under the optimum conditions, analytical performance values were examined, and limit of detection values were obtained as 286 ng mL-1 for FAAS, 137 ng mL-1 for SQT-FAAS, 7.9 ng mL-1 for DLLME-FAAS and 3.9 ng mL-1 for DLLME-SQT-FAAS. The enhancement in detection power was obtained as 82-folds over the detection limit of the conventional FAAS system. Chinese green tea sample was used in recovery studies to check applicability and accuracy of the developed method. Recovery results were close to 100 % with low standard deviation values (n = 4) and this showed that the method appropriate for the selected matrix.

Determination of trace nickel in chamomile tea and coffee samples by slotted quartz tube-flame atomic absorption spectrometry after preconcentration with dispersive liquid-liquid microextraction method using a Schiff base ligand

In the present study, an accurate and selective preconcentration/extraction method was developed for the determination of nickel at trace levels. Slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) combined with dispersive liquid-liquid microextraction (DLLME) was used to obtain a very low detection limit for nickel. A Schiff base ligand derived from the reaction of 5-bromosalicylaldehyde and o-phenylenediamine was used for the formation of a coordinate nickel complex. Under the determined experimental conditions, the detection and quantification limits of the DLLME-SQT-FAAS system were calculated as 4.9 and 16.4 ng/mL, respectively. Satisfactory analytical performance values of the SQT-FAAS, DLMME-FAAS and DLLME-SQT-FAAS methods were obtained and 1.8, 32.0, 66.4-fold enhancements in detection power were respectively obtained over the conventional FAAS system. The percent recovery ranges obtained for two different spike concentrations were 88.1–113.2% and 102.1–120.2% for coffee and chamomile tea samples, respectively.

A simple dilution method for the direct determination of trace nickel in crude oil with a miniaturized electrothermal atomic absorption spectrometer

A simple procedure for the direct determination of trace nickel in crude oil samples has been proposed using a miniaturized electrothermal atomic absorption spectrometer (ETAAS).

Inductively coupled plasma mass spectrometry coupled to cation exchange chromatography for the determination of trace nickel in alkaline electrolyte

Cone corrosion by alkaline solutions with flow injection is prevented using cation-exchange chromatography coupled to inductively coupled plasma mass spectrometry.

Determination of Trace Nickel in Spinach Samples Using the Combination of Vortex-assisted Deep Eutectic Solvent-based Liquid Phase Microextraction and Slotted Quartz Tube - Flame Atomic Absorption Spectrometry

Determination of Trace Nickel in Spinach Samples Using the Combination of Vortex-assisted Deep Eutectic Solvent-based Liquid Phase Microextraction and Slotted Quartz Tube - Flame Atomic Absorption Spectrometry

Determination of Trace Nickel in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Mixed Micelle-Mediated Cloud Point Extraction

A simple and sensitive cloud point extraction method for the preconcentration of ultra-trace amounts of nickel as a prior step to its determination by graphite furnace atomic absorption spectrometry was proposed. It is based on the reaction of nickel with 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in HAc–NaAc buffer media and mixed micelle-mediated extraction of the complex using the anionic surfactant sodium dodecyl sulfate sodium (SDS) and non-ionic surfactant (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene (Triton X-114). The optimal reaction and extraction conditions such as pH, concentration of 5-Br-PADMA, SDS and Triton X-114, equilibrium temperature, incubation, and centrifuge time were evaluated and optimized. Under the optimal conditions, the calibration graph was linear over the range 0.1–5.5 ng/mL of nickel with a correlation coefficient of 0.9942. The detection limit obtained was 0.031 ng/mL, and the relative standard deviation was 2.1% for nickel (c = 2 ng/mL, n = 6). The proposed method was successfully applied to the determination of nickel in water samples.

Trace determination of nickel in water samples by slotted quartz tube-flame atomic absorption spectrometry after dispersive assisted simultaneous complexation and extraction strategy.

This study presents a new method for the determination of nickel in aqueous samples by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after a dispersive assisted simultaneous complexation and extraction (DASCE) process. Synthesized ligand was directly dissolved in the extraction solvent to eliminate the complex formation step prior to the extraction. All parameters of the SQT-FAAS and DASCE method were systematically optimized to improve the detection power of nickel for trace determinations. Under the optimum experimental conditions, the optimized method (DASCE-SQT-FAAS) recorded 137-fold enhancement in detection power over the conventional FAAS. The limits of detection and quantification were determined to be 1.6μg/L and 5.2μg/L, respectively. The calibration plot was linear over a wide concentration range and the precision for replicate measurements was appreciably high. Nickel was not detected in five different water samples but spiked recovery tests for three samples yielded results that were close to 100%, confirming the method's accuracy and applicability to the matrices tested.

Preconcentration and Determination of Trace Nickel and Cobalt in Milk-Based Samples by Ultrasound-Assisted Cloud Point Extraction Coupled with Flame Atomic Absorption Spectrometry.

In this study, ultrasound-assisted cloud point extraction (UA-CPE) method was developed for the determination of Ni(II) and Co(II) in milk-based products. After extraction and preconcentration, the Ni(II) and Co(II) contents of samples were determined by flame atomic absorption spectrometry (FAAS). After their complexation with hydroxy naphthol blue (HNB) in the presence of cationic surfactant, CTAB at pH 4.0, the Ni(II) and Co(II) were taken within the micellar phase of nonionic surfactant, TX-114. The micellar phase containing the analytes were diluted to a volume of 0.7mL with 1.0-mol/L HNO3 in ethanol to reduce its viscosity and to facilitate sample treatment and then was analyzed by FAAS. The various analytical parameters affecting UA-CPE efficiency were investigated. The analytical features obtained after optimization are as follows: limits of detection are 0.56 and 0.78μg/L; sensitivity enhancement factors are 48.6 and 53.9; the calibration curves were linear 3-180 and 2-160μg/L for Co(II) and Ni(II), respectively, after preconcentration of 50-fold. The precision (as RSD%) between 1.8-3.6% and 2.2-3.8% (25 and 100μg/L, n = 5) for Ni(II) and Co(II), respectively. The accuracy was statistically verified by analysis of two certified reference material samples (CRMs), including recovery studies after spiking. The method was applied to the analysis of milk-based samples with satisfied results.

Development and Validation of a Sensitive Method for Trace Nickel Determination by Slotted Quartz Tube Flame Atomic Absorption Spectrometry After Dispersive Liquid-Liquid Microextraction.

In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1µgL-1. Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method.

Use of a new magnetic ion–imprinted nanocomposite adsorbent for selective and rapid preconcentration and determination of trace nickel by flame atomic absorption spectrometry

Selective and rapid preconcentration of trace Ni(ii) in environmental water by solid-phase extraction using a magnetic Ni(ii)–imprinted nanocomposite as the adsorbent.

Determination of Trace Nickel in Natural Water by Flow Injection Analysis with Cetrimonium Bromide as Sensitizer

2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is a highly sensitive chromogenic reagent that can react with most of the transition and alkaline earth metals. The Ni(II)-5-Br-PADAP complex is more stable than other metal–5-Br-PADAP complexes. In the presence of seignette salt, ethylenediaminetetraacetic acid (EDTA) can decompose most of the 5-Br-PADAP complexes with metals except for iron, cobalt, and nickel. Cetrimonium bromide (CTMAB) as a sensitizer for the color reaction forms a ternary complex with nickel and 5-Br-PADAP with maximum absorption wavelength at 561 nm. CTMAB can significantly improve the sensitivity and selectivity of nickel determination, as well as the stability and solubility of compounds. In this study, the determination of trace nickel in natural water samples was performed by flow injection analysis. The calibration lines were established in the range of 0–200 μg/l of nickel (n ≥ 3), and the limit of detection was 0.093 μg/l. The relative standard deviation was 2.55% for the determination of 25 μg/l nickel (n ≥ 20). The recoveries of this method ranged from 91.0 to 101% for environmental water samples. A large amount of aluminum, calcium, cadmium, copper, bicarbonate, magnesium, zinc, and iron, except for cobalt, did not interfere with the determination of nickel.

Synthesis of a new ion-imprinted polymer and its characterization for the selective extraction and determination of nickel ions in aqueous solutions

A new ion-imprinted polymer (IIP) was synthesized by bulk polymerization from 2-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (EGDMA; the cross-linker), 2, 2′- azobisisobutyronitrile (the initiator), diphenylcarbazone (the ligand), and nickel nitrate (the template ion) in acetonitrile solution. The prepared IIP was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy, and studied for the preconcentration and determination of trace nickel ion from aqueous solutions using inductive couple plasma optical emission spectroscopy. The optimal pH value for the quantitative preconcentration was 6.0 and maximum sorbent capacity was 3.26 mg g−1. Under the optimized conditions, the method had a linear analytical range from 0.5 to 50 μg L−1. The detection limit, relative standard deviation, and recovery of the method were evaluated as 0.38 μg L−1, 3.6% and 95–98%, respectively. The developed method was successfully applied to the selective extraction and determination of trace nickel in synthetic and real water samples and some medicinal plants with satisfactory results.

Dispersive Liquid–Liquid Microextraction of Nickel Prior to Its Determination by Microsample Injection System-Flame Atomic Absorption Spectrometry

A sensitive and simple method for the determination of trace nickel was developed by the combination of dispersive liquid–liquid microextraction (DLLME) and microsample injection system–flame atomic absorption spectrometry (MIS–FAAS). Trace nickel was preconcentrated as the 8-hydroxyquinoline chelate by DLLME, and the conditions were optimized by a Plackett-Burman design. Quantitative recovery of nickel (98 ± 1%) was obtained by a sample volume of 7.5 mL at a pH of 6.0. The enrichment factor was 52.5, and the limits of detection and quantitation were 0.1 µ g L−1 and 3.0 µ g L−1, respectively. The method was validated by the analysis of a wastewater standard reference material, water samples, and a wire sample. The reported method has superior analytical figures of merit compared with similar methods reported in the literature.

Determination of Trace Nickel by Inductively Coupled Plasma Mass Spectrometry after Pre concentration/Separation with Monoclinic Fusiform Nanometer-Size Zirconium Dioxide

Determination of Trace Nickel by Inductively Coupled Plasma Mass Spectrometry after Pre concentration/Separation with Monoclinic Fusiform Nanometer-Size Zirconium Dioxide

Cold-Induced Aggregation Microextraction Technique based on Ionic Liquid for Preconcentration and Determination of Nickel in Food Samples

The determination of nickel in food samples and well water using cold induced aggregation microextraction combined UV-Vis spectrophotometry is described. The extraction of nickel was performed in the presence of dimethylglyoxime (DMG) as the complexing agent. In this method, sodium hexafluorophosphate (NaPF6) was added to the sample solution containing small amounts of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF6] as extraction solvent. Parameters governing the extraction efficiency such as amount of ionic liquid, pH, temperature and ionic strength were optimized. The applicability of the technique was evaluated by the determination of trace nickel in different types of vegetables. Under the optimum conditions, the calibration curve was linear in the concentration range 8-200 ng mL-1 with correlation coefficient (r2) of 0.9996. The limit of detection (LOD) of 0.47 ng mL-1 and enhancement factor of 186 were obtained for nickel. The relative standard deviation (RSD) was 3.7% for 40 ng L-1 nickel (n = 10).