Determination Of Trace Copper Research Articles

Electrochemical determination of trace copper(ii) based onl-cysteine functionalized gold nanoparticle/CdS nanosphere hybrid

This paper describes a simple and efficient electrochemical assay for the determination of trace Cu(ii) employingl-cysteine functionalized gold nanoparticles/CdS nanospheres/glassy carbon electrode (l-cys/AuNPs/CdS/GCE) as an enhanced sensing platform.

Magnetic molecularly imprinted polymer nanoparticles for selective extraction of copper from aqueous solutions prior to its flame atomic absorption determination

This paper describes a pre-concentration procedure using magnetic molecularly imprinted polymer (MMIP) nanoparticles for the extraction of copper(II) from aqueous samples prior to its atomic absorption determination. Cu–morin complex was used as template molecule which was chemically bonded to MMIP nanoparticles. MMIP nanoparticles were characterized by scanning electron microscopy as well as Fourier transform infrared spectroscopy. The extraction conditions including pH value, adsorption and desorption time, temperature, amount of ligand and ionic strength of the sample matrix were studied and optimized. The method showed good extraction recoveries (≥96%) with relative standard deviation below 3.4% for real samples. The linear range of calibration curve was between 5–1000 μg/L with a correlation coefficient (r 2) of 0.996. The detection limit was 0.5 μg/L. The method was suitable for the determination of trace copper in drinking water samples.

Optimization of stripping voltammetric sensor by mixture design-artificial neural network-genetic algorithm for determination of trace copper(II) based on iodoquinol-carbon nanotube modified carbon paste electrode

In this work, differential pulse cathodic stripping voltammetry method has been developed for determination of Cu (II) ions in aqueous solutions using a carbon paste electrode (CPE) modified with iodoquinol and multi-walled carbon nanotubes. The factors affecting the performance of the modified carbon paste electrode (MCPE) including the electrode composition and pH were optimized. The optimization process was performed using experimental design, artificial neural network (ANN) and genetic algorithm (GA). At first, experiments were performed using mixture design with pH factor as the process variable. The data from mixture design including experimental conditions and results were used to train the ANN using Bayesian regularization. The ANN was trained over 211 iterations with mean square error (MSE) of 1.60 and regression ocoefficient of r=0.9328. The predicted model obtained from the trained ANN was introduced to GA as the fitness function to be optimized. GA optimized the fitness function using the defined constraints. Under optimal conditions a linear calibration graph in the range 0.01–5μM was obtained. The square of regression coefficient was obtained 0.9880. The limit of detection (3S/N) was obtained 0.005μM. The real samples analysis was performed to determine trace copper (II) in some oil and water specimens. The repeatability and reproducibility of method (n=3) were obtained 3.31 and 4.12%, respectively. The shelf life of the sensor was obtained at least 4 months.

Fluorene functionalized nanoporous SBA-15 incorporated into carbon paste electrode for trace copper determination

In this study, fluorene 3-[2-(2-aminoethylamino)ethylamino]propyl trimethoxy silane functionalized nanoporous SBA-15 was incorporated into carbon paste electrode for the potentiometric detection of Cu2+ ions in aqueous medium. With 15.5 wt% FT-SBA-15 proportion, the developed electrode exhibited wide dynamic range of 1.0 × 10−6–1.0 × 10−2 mol L−1 toward Cu2+ with a detection limit of 5.0 × 10−7 mol L−1 and a Nernstian slope of 29.6 ± 1.0 mV decade−1. The electrode displayed rapid response (~44 s), long-term stability (more than 6 months) and high sensitivity. Moreover, the potentiometric responses could be carried out with a wide pH range of 3.9–6.6. Finally, the proposed electrode was successfully used as an indicator electrode in potentiometric titration of copper ions with EDTA and to determine the concentration of copper ions in seawater, tap water and black tea samples. The results showed a good correlation with the data obtained by graphite furnace atomic absorption spectrometry method.

Determination of Trace Copper in Vanadium Alloy by Flame Atomic Absorption Spectrometry

The determination method for analyzing trace copper in vanadium alloy by flame atomic absorption spectrometry was investigated in the paper. The sample digestion method, digestion acidity, determination conditions, matrix interferences, method precision, recovery of standard addition were investigated in detail. The method precision in RSD% was 8.6%, and the average recoveries of standard addition were from 93.9% to 95.6%. The experimental results indicated that the proposed method for determination of trace copper in vanadium alloy was simple, fast, accurate, and easy to operate, which was suitable for quality control of vanadium alloy.

Comparison of ultrasound-assisted cloud point extraction and ultrasound-assisted dispersive liquid liquid microextraction for copper coupled with spectrophotometric determination

In this work, ultrasound-assisted cloud point extraction (UA-CPE) and ultrasound-assisted dispersive liquid liquid microextraction (UA-DLLME) were investigated and compared firstly as ultrasound-assisted liquid phase microextraction methods, which were coupled with spectrophotometer for copper preconcentration and detection. Compared to conventional CPE and DLLME, the extraction patterns were changed and improved by the effect of ultrasound. As novel methods, their applications were expanded and the analytical performance of spectrophotometric determination for copper was considerably improved. The influence factors of UA-CPE and UA-DLLME were studied in detail. Under the optimal conditions, the limits of detection (LODs) for copper were 0.7μgL−1 of UA-CPE and 0.8μgL−1 of UA-DLLME with sensitivity enhancement factors (EFs) of 17 and 16. The developed methods were applied to the determination of trace copper in real water samples with satisfactory analytical results.

Preparation of a new Cu(II)-imprinted polymer and its application for the determination of trace copper in water samples by flame atomic absorption spectrometry

A new Cu(II)-imprinted polymer has been prepared for selective solid-phase extraction of Cu(II) prior to its determination by flame atomic absorption spectrometry. Two functional monomers, 4-(methacryloylamino)benzamide and 4-vinylpyridine, formed a complex with Cu(II) ion through coordination interactions. The self-assembled Cu(II)-monomer complex was copolymerised via bulk polymerisation method in the presence of ethyleneglycoldimethacrylate cross-linker. In order to remove Cu(II) ions, the resulting polymer was washed with 1.0 M HNO3 and then with water until obtaining a neutral pH. The ion imprinted polymer was characterised by Fourier transform infrared. The experimental conditions were optimised for solid-phase extraction of Cu(II) using a column of ion-imprinted polymer (IIP). Quantitative retention was achieved between pH 5.0 and 7.0, whereas the maximum recovery for the non-imprinted polymer (NIP) was about 74% at pH 7.0. The IIP showed higher selectivity to Cu(II) in comparison to the NIP. The IIP also exhibited excellent selectivity for Cu(II) in the presence of other metal ions. The relative standard deviation and limit of detection (3s) of the method were 1.6% and 1.8 µg L−1, respectively. The method was verified by analysis of two certified reference materials (CWW-TM-D and SRM 3280) and then applied to the determination of Cu(II) in seawater and lake water samples and haemodialysis concentrates.

Novel modified carbon nanotubes as a selective sorbent for preconcentration and determination of trace copper ions in fruit samples.

In this work, multiwalled carbon nanotubes were reacted with N-[3-(triet-hoxysilyl)propyl]isonicotinamide to prepare pyridine-functionalized carbon nanotubes. This novel sorbent was characterized by infrared spectroscopy, thermal and elemental analysis, and scanning electron microscopy. Functionalized carbon nanotubes were applied for the preconcentration and determination of copper ions using flame atomic absorption spectrometry. Various parameters such as sample pH, flow rate, eluent type and concentration, and its volume were optimized. Under optimal experimental conditions, the limit of detection, the relative standard deviation, and the recovery of the method were 0.65 ng/mL, 3.2% and 99.4%, respectively. After validating the method using standard reference materials, the new sorbent was applied for the extraction and determination of trace copper(II) ions in fruit samples.

Enhancement of stripping technique for Copper(II) detection in water sample using N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME)

A highly sensitive, rapid, simple and selective stripping assay for the determination of trace copper(II) is proposed. The selectivity and sensitivity of the electroanalytical process on a glassy carbon (GC) electrode were enhanced using the newly synthesized Schiff base N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME). The methodology is based on the accumulation of copper(II)–BME complex onto the GC electrode, followed by electrochemical oxidation of the adsorbed species. The effect of experimental parameters such as pH, BME concentration, scan rate, accumulation time and accumulation potential on the sensitivity of copper(II) detection were investigated. Under the optimal conditions, BME has successfully enhanced the copper(II) detection using the GC electrode by nearly 95% with detection limit (LOD) of 2.6 ngL−1. The effects of interfering ions such as Cd(II), Zn(II), Fe(II), Cr(III) and Pb(II) were also investigated. The applicability of this technique was illustrated by the determination of copper(II) ion in tap water.________________________________________GRAPHICAL ABSTRACT

Magnetic Fe3O4@C nanoparticles modified with 1-(2-thiazolylazo)-2-naphthol as a novel solid-phase extraction sorbent for preconcentration of copper (II)

We report on a new magnetic nanosorbent for solid phase extraction of Cu(II) before its determination by flame atomic absorption spectrometry. The magnetic sorbent is composed of carbon-coated magnetite nanoparticles (Fe3O4@C) synthesized by a single-step solvothermal reaction and then loaded with the chelator 1-(2-thiazolylazo)-2-naphthol. It was used for the preconcentration of Cu(II) ions from water and food samples. The effects of pH value and volume of sample, of type and volume of eluent, and of interfering ions were investigated. Under the optimum conditions, the calibration graph is linear in the 4.0–400 μg L−1 concentration range, with a detection limit of 1.5 μg L−1. The method was validated by using a certified reference material (NIST 1566b; oyster tissue) and applied to the determination of trace copper in spiked water and food samples.

Spectrophotometric determination of trace copper(II) in biological samples with 2,4-bis(4-phenylazophenylaminodiazo)phenol

A highly sensitive and selective chromogenic reagent 2,4-bis(4-phenylazophenylaminodiazo)phenol (BPPAAP) reacted with copper(II) to form a highly stable complex in the ethanolic solution at pH range of 9.0–12.0. The Cu(II)-BPPAAP complex showed maximum absorbance at 540 nm, with molar absorptivity being 1.86 × 105 L/mol cm. Beer’s law was obeyed over the range 0–0.2 μg/100 mL of copper(II) and variation coefficient is found to be 2.4–4.8%. The detection and quantification limit of the method are 2.0 and 6.5 ng/mL, respectively. To eliminate the interference of foreign ions, a convenient and efficient method using a column packed with sulfhydryl dextrose gel as a solid-phase extractant was utilized with satifactory reults. The developed method has been successfully employed for the determination of copper(II) in the biological samples.

Determination of trace copper(ii) by Triton X-100 sensitized fluorescence quenching of a novel calix[4]arene Schiff base derivative

Fluorescence quenching by copper(II) of a Schiff base derivative of p-tert-butylcalix[4]arene (SANCAX) in 0.1% polyethylene glycol tert-octylphenyl ether (Triton X-100) medium was investigated. The fluorescence of SANCAX is quenched by Cu2+ due to the formation of a weaker fluorescent inclusion complex (Cu-SANCAX). The fluorescence quenching (ΔF = FSANCAX − FCu-SANCAX) is sensitized in Triton X-100. Under optimal conditions, the linear range calibration curve for the determination of Cu2+ is 0.005–0.08 μg mL−1. The detection limit is 3.05 ng mL−1 with an RSD of 1.55% (n = 3, c = 0.05 μg mL−1). The SANCAX fluorescence quenching mechanism was investigated by the Benesi–Hildebrand method, fluorescence quantum yield, and IR. The method has been applied in the determination of trace Cu2+ in real samples with satisfactory results.

Spectrophotometric Determination of Trace Copper(II) in Biological Samples with 2,4-bis(4-Phenylazophenylaminodiazo)phenol

Spectrophotometric Determination of Trace Copper(II) in Biological Samples with 2,4-bis(4-Phenylazophenylaminodiazo)phenol

Gold Microelectrode Arrays Based Electrode for Determination of Trace Copper in Seawater

We report a novel and facile gold microelectrode array (Au MEA) for the determination of trace Cu2+ by differential pulse anodic stripping voltammetry (DPASV). The gold microelectrode array was fabricated by a multi-step micro-fabrication approach combining sputtering for the deposition of metals and the dielectric material (SiO2) on the surface of a silicon wafer and photolithography for the definition of the geometry of the electrode. Due to the rapid mass transporting and low background current of gold microelectrode array, low detection limit (1.3 pM) and wide linear range (10-150 pM) can be obtained for the determination of Cu2+. The practical application of the proposed electrode has been carried out for the determination of trace level of Cu2+ in real seawater sample.

Interference-Free Determination of Trace Copper in Freshly Ripened Honeys by Flame Atomic Absorption Spectrometry Following a Preconcentration by Solid-Phase Extraction and a Two-Step Elution Process

A fast and straightforward procedure aimed at separating copper (Cu) ions from monosacharides and preconcentrating their traces before flame atomic absorption spectrometry (FAAS) measurements was developed, and its suitability was evaluated by the analysis of freshly ripened honeys on the content of this environmentally and physiologically relevant element. This procedure included the passage (at 20 mL/min) of 10 % (m/v) solutions of honeys (100 mL) through resin beds of Dowex 50 W × 8-400 to retain Cu by solid-phase extraction (SPE) and separate it from the glucose and fructose matrix. In turn, SPE columns were rinsed at 20 mL/min with 20 mL of water and subsequently washed with 20 mL of a 0.5 mol/L HNO3 solution (at 2.0 mL/min) to elute potassium and sodium. Preconcentrated Cu was stripped (at 2.0 mL/min) with 5.0 mL of a 2.0 mol/L HCl solution and determined by FAAS. The proposed procedure was used for the analysis of six ripened monoflower and multiflower honeys, enabling the measurement of Cu within the range of 0.17–0.42 μg/g and with a precision of 3–10 %. Recoveries of Cu added to respective honey solutions were within 94–102 %, proving the good accuracy of this procedure. The detection limit of Cu achieved with this SPE preconcentration/separation procedure and FAAS detection was 3.6 ng/g.

Synthesis and application of surface-imprinted activated carbon sorbent for solid-phase extraction and determination of copper (II)

A new Cu(II)-imprinted amino-functionalized activated carbon sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Cu(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of Cu(II) were optimized with respect to different experimental parameters using static and dynamic procedures in detail. Compared with non-imprinted sorbent, the ion-imprinted sorbent had higher selectivity and adsorption capacity for Cu(II). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cu(II) was 26.71 and 6.86mgg−1, respectively. The relatively selectivity factor values (αr) of Cu(II)/Zn(II), Cu(II)/Ni(II), Cu(II)/Co(II) and Cu(II)/Pb(II) were 166.16, 50.77, 72.26 and 175.77, respectively, which were greater than 1. Complete elution of the adsorbed Cu(II) from Cu(II)-imprinted sorbent was carried out using 2mL of 0.1molL−1 EDTA solution. The relative standard deviation of the method was 2.4% for eleven replicate determinations. The method was validated for the analysis by two certified reference materials (GBW 08301, GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace copper in natural water samples with satisfactory results.

Study on Spectrophotometric Determination of Trace Copper after Flotation Separation Using Microcrystalline Adsorption System Loaded with CuI

The paper presents a novel method for the flotation separation of Cu2+ using microcrystalline adsorption system loaded with CuI prior to the determination by spectrophotometry. The effects of different parameters,such as the dosages of KI, ascorbic acid and octadecyl trimethyl ammonium bromide (OTMAB),various salts and acidity etc. on the flotation yield of Cu2+ have been investigated. The possible flotation separation mechanism of Cu2+ was discussed.The results showed that under the optimum conditions,octadecyl trimethyl ammonium bromide cation (OTMAB+) reacted with I- to produce the microcrystalline matter (Ms-M) of (OTMAB+·I-), Cu2+ could be reduced to Cu+ by ascorbic acid,and then Cu+ reacted with I- to form the precipitation of CuI.The precipitation of CuI was quantificationally adsorbed on the surface of Ms-M of (OTMAB+·I-) and was floated above water phase, the liquid-solid phases were formed with clear interface. In this condition, K+,Na+,Ca2+,Mg2+, Zn2+,Co2+,Al3+,Mn2+,Ni2+ and Fe2+ could not be floated.Therefore, Cu2+ was separated completely from the above metal ions.A new spectrophotometric method of determination of trace copper by flotation separation using microcrystalline adsorption system loaded with CuI was established.The proposed method has been successfully applied to the determination of Cu2+ in various environmental water samples, and the results agreed well with those obtained by AAS method.

Determination of Trace Copper in Environmental Samples by Flame Atomic Absorption Spectrometry After On-line Selective Preconcentration with Thioacetamide Modified Silica Gel Mini-Column

Determination of Trace Copper in Environmental Samples by Flame Atomic Absorption Spectrometry After On-line Selective Preconcentration with Thioacetamide Modified Silica Gel Mini-Column

Determination of Trace Copper with Sulfophenylazo Rhodanine by Catalytic Dynamic Spectrofluorimetry

Series new methods were established which were based on the research of determination of trace copper with four sulfophenylazo rhodanine derivatives by catalytic dynamic spectrofluorimetry under the optimum conditions. This proposed method was applied to the determination of copper in real samples with satisfactory results. According to experiment results, the influences of different active groups and substitution positions on fluorescent property of rhodanine derivatives were investigated and the relationship between molecule structure and fluorescent property was explored.

Cloud point extraction for the determination of trace copper(II) in environmental samples using a new synthesized reagent and flame atomic absorption spectrometry

Cloud point extraction for the determination of copper(II) is proposed after the formation of a complex with sulfapyridylazo resorcinol (SPAR) and later measurement by flame atomic absorption spectrometry (FAAS) using Triton X-100 as a surfactant. The surfactant-rich phase was diluted with nitric acid in methanol, prior to FAAS measurement. Analytical parameters including pH, concentration of the chelating agent and surfactant, equilibration temperature and time were optimized. The effects of matrix ions on the recovery of copper ions were also studied. A detection limit of 1.64 μg L−1 along with an enrichment factor of 31 for Cu were achieved. The method was successfully applied to the determination of copper in tap water, stream water, rain water and a standard reference material.