Copper(II) Determination by Immobilized Urease Inhibition in a Spectrometric Flow-Injection System (original) (raw)
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Microchimica Acta, 2008
This work describes the synthesis and characterization of 2-aminothiazole modified silica gel (SiAT) and the studies of adsorption and pre-concentration (in batch and using a flow-injection system coupled with optical emission spectrometer) of Cd(II), Cu(II) and Ni(II) in aqueous medium. The adsorption capacity for each metal ions in mmol g À1 was: Cu(II) ¼ 1.18, Ni(II) ¼ 1.15 and Cd(II) ¼ 1.10. The results obtained in the flow experiments showed about 100% of recovering of the metal ions adsorbed in a minicolumn packed with 100 mg of SiAT, using 100 mL of 2.0 mol L À1 HCl solution as eluent. The quantitative sorption-desorption of the metal ions made possible the application of a flow-injection system in the preconcentration and quantification by ICP-OES of metal ions at trace level in natural water samples.
International Journal of Electrochemical Science, 2017
The present work tends to introduce a new selective ion-carrier (i.e. 4-(2-hydroxy-benzylideneamino)-5-phenyl-4H-1,2,4-triazole-3-thiol (L)) for Cu 2+ ions. The study, hence involved complexation studies in acetonitrile solutions of different ions which proved a selective interaction between the ion-carrier and copper as opposed to alkali, alkaline earth, and transition metal cations. Based on the complexation observations L was evaluated for use as a new sensing agent in copper selective membrane sensors and the optimal sensor responses were observed at a membrane composition of 30% PVC, 62% NPOE, 6% L and 2% NaTPB. The potentiometric sensors produced stable potential responses towards Cu 2+ ion, and the slope of the calibration curve was 28.7±0.4 mV decade-1 over the range of 1.0×10-6 to 1×10-2 mol L-1 for polymeric membrane electrodes (PMEs) and 28.5±0.3 for all solid state electrodes (ASSEs) in the range of 1.0×10-8 to 1×10-4 mol L-1. The response time of the sensors was rather short (i.e. about 25s in the case of PMEs and 15 s for the ASSEs) and both devices showed acceptable life times of 5 weeks for the PMEs and 7 weeks in the case of the ASSEs. The electrodes were used for the determination of the copper content of some water samples, and the results proved to be acceptable.
2013
Trace amount of Copper(II) has determined by spectrophotometric technique using 1-(2-pyridylazo)- 2-naphthal (PAN), as a new spectrophotometric reagent which is insoluble in water. PAN reacts in highly acidic solution at pH 2.40 to 2.50 with Cu(II) to give a pink chelate which has an absorption maximum (λmax.) at 550nm. The reaction is instantaneous and absorbance remains stable for over 48hrs. The average molar absorption co- efficient (e) was found to be 2.05×10 4 L mol -1 cm -1 and Sandell sensitivity is 3.23×10 −4 μg cm −2 . Linear calibration graphs were obtained for 0.1-4.0 μgL -1 of Cu(II) and RSD (%) is 1.16. The stoichiometric composition of the chelate is 1:2 (Cu:PAN). Large excess of over 50 cations, anions, and some common complexing agents (e.g. oxalate, phosphate, tartarate, thio-urea) do not interfere in the determination. The method was successfully used in the determination of Cu(II) in Several Standard Reference Materials as well as in some environmental and indust...
Talanta, 2012
The paper presents application of a new resin dedicated to copper(II) flow-injection on-line preconcentration prior its flame atomic absorption spectrometric (FAAS) determination. The new sorbent, obtained by suspension polymerization technique, was styrene-divinylbenzene copolymer modified with 5-dodecylsalicylaldoxime-copper(II) complex. In flow mode leaching of initially imprinted Cu(II) ions from polymer beads was effective with 1% (v/v) nitric acid, however for elution of ions retained on the sorbent during the loading process sufficient efficiency was obtained for 0.5% (v/v) nitric acid. The most effective copper(II) sorption was observed within sample pH ca. 6.3 at flow rate 7.5 mL min −1. Furthermore, preconcentration studies of Cu(II) ions realized in the presence of popular foreign ions like Cd(II), Pb(II), Zn(II), Ni(II), Mn(II), Co(II) did not reveal significant interference. The expected effect of Cu(II)-imprinting was confirmed by higher tolerance level for interferents ions concentration for the new sorbent than for the control polymer. It was found that alkaline metals ions and humic acid had the most relevant influence on copper(II) uptake. Accuracy of the evaluated method was assessed for analysis of water samples (tap and mineral water, river water, artesian water) and certified water reference materials compare them to results obtained by inductively plasma mass spectrometry. The satisfactory relative error values obtained with use of standard addition calibration method, confirms the feasibility of this method for Cu(II) determination in water samples. Application of 120 s sorption time enabled to obtain 74-fold enrichment factor and limit of detection (3) equal to 0.4 g L −1 .
In the present study, an enrichment and separation method for the simultaneous determination of trace amounts of Cu and Zn in water samples was developed. Copper and Zn ions found in water matrix in trace amounts were preconcentrated on Duolite XAD 761 resin without using any chelating agent and determined by flame atomic absorption spectrometer (FAAS). Experimental parameters such as pH, concentration of metal ions, amount of resin, and sample volume for quantitative determination of Cu and Zn ions were optimized. The elution process was performed by using 5ml of 2 mol/L HCl solution. The preconcentration factors for Cu and Zn were found to be 160 and 200, respectively. Under optimized conditions, limit of detection for Cu and Zn were 2.46 and 3.54 mg/L, respectively. The Langmuir adsorption model was applied to describe the equilibrium isotherm. The Langmuir monolayer adsorption capacity of resin was estimated as 31.2 and 17.7 mg/g for Cu and Zn, respectively. The proposed method was successfully applied to determine the Cu and Zn content of various water samples.
Cu(II) removal from aqueous solutions: A Review
Copper is a widely known toxic as well as poisonous metal to the living organism with a permissible concentration of 50 μg/litre in aqueous solutions. It is necessary to provide a suitable, environment friendly and cost effective copper removal process to save the world. The biosorption technique was found to be an effective method for the treatment and removal of copper from aqueous solution. The use of eco-friendly and low-cost biosorbent as well as biosorbent regeneration are the effective means of using biosorption techniques for the removal of copper from aqueous solutions. However, this review present the various techniques used in the treatment and removal of copper from aqueous solution with emphasis on biosorption technique.
1979 The adsorption characteristics of Cu(II) in the presence of chelation agents (Elliott).pdf
The adsorption characteristics of Cu(II) in the presence of chelating agents was investigated in the laboratory. The results showed that the presence of chelating agents improved the extent of Cu(II) adsorption, although ligand:Cu(II) ratio = 1:1 seemed to be important to assure optimum Cu(II) adsorption, at least in the Cu(II)-NTA-y-AI2Oz system. Electrostatic interaction appeared to be an important mechanism for complexed Cu(II) adsorption. However, a finite adsorption of Cu(II) complexes of NTA, glycine, and aspartic acid was observed at the pH~w of y-A1203. This suggests the presence of specific chemical interaction. The adsorbed Cu(II) species in the presence of chelating agents, such as NTA, is the complexed form, i.e., CuNTA-. A model has been proposed to qualitatively explain the attachment of CuNTA-species onto y-AlzO3 surface.