Retention profile of Fe,Mn and Cu onto chemically treated polyurethane with carbon disulfide

Dithiocarbamate modified polyurethane foam (DTC-PUF) was synthesized as a new solid-phase extraction sorbent for the preconcentration and determination of Fe(II), Mn(II) and Cu(II) in environmental samples using flame atomic absorption spectrometry. Maximum extraction of the elements was achieved at pH 5–7 and flow rate 3 mL min^?1. Quantitative desorption was achieved by 10 mL from 1.0 mol L^?1 HCl solution. The capacity of the sorbent was 149.2 ± 0.5, 237.5 ± 0.2, 200.2 ± 0.1 μg g^?1 and the limit of detection was of 0.015, 0.015 and 0.012 μg mL^?1for Fe(II), Mn(II) and Cu(II), respectively. A preconcentration factor of 100 was obtained for all elements. The developed method was successfully applied to the determination of the tested elements in water (tap and lake) and plant (spinach and parsley leaves) samples and showed good recovery values from 98 to 111% with corresponding RSD values ranged from 0.6 to 8.6%.     

Spectrophotometric study of some Mn(II) ternary complexes and their analytical applications

Abstract  

New ternary complexes of Mn(II) with py, bipy, and terpy as primary ligand (L₁) and 2′,4′,5′,7′-tetraiodofluorescein (I₄FlCOOH) as secondary ligand (L₂) were prepared. The stoichiometry for these complexes was found to be Mn(II):L₁:L₂ = 1:2:1, and the complex formula proposed is [Mn(L₁)₂(I₄FlCOO)]⁺. The effect of substituent groups of L₂ and the nitrogen atoms of L₁ on complex formation with Mn(II) was studied. Moreover, the interference of some cations and anions in the determination of Mn(II) by this method was investigated and the interferences of Cu(II) and Fe(III) with Mn(II) in their corresponding alloys were considered. A simple, rapid, and sensitive spectrophotometric method for determination of Mn(II) in its salts and Mn in its alloys is suggested.     

Solvent extraction of Mn/II/ with 2-propionyl, 1-naphthol oxime/2-PRONAPOX/ into chloroform

A rapid method has been described for the quantitative extraction of milligram amounts of Mn/II/ with 2-PRONAPOX into CHCl₃. The extraction coefficient /E/ of Mn/II/ between CHCl₃ and aqueous solution containing 0.2M NH₄Cl shows a maximum value of E=143 at pH 10.5. The percentage extraction is better than 98% in the pH range from 9 to 11 and an equilibration time of 6 min. The effects of anions and cations have been studied. The stoichiometry of metal: reagent determined by substoichiometric extraction and slope ratio method is found to be 12. The decontamination factors for most of the elements are better than 10⁴ in the substoichiometric extraction of Mn/II/.     

A Heterogeneous Precipitate Based Mn(Ii) Coated Wire Ion-Selective Electrode

Abstract

A new heterogeneous Mn(II) ion selective coated wire electrode (CWISE) based on tetrapyridine Mn(II) thiocynanate as electroactive material has been described. the working pH range of the electrode is 2.3 to 8.8. the electrode shows a linear response in the concentration range 1.0×10^?1M to 1.0×10^?6M. the response time of the electrode is 35 sec. the selectivity coefficient for different cations determined by mixed solution method are:

Fe²⁺(0.05), Cd²⁺(0.05), Ni²⁺(0.01), Co²⁺(0.5), Pb²⁺(0.5), Hg²⁺(0.05), Sn²⁺(0), Zn²⁺(0)

The electrode can be used for the electrometeric determination of Mn(II) ion.     

Iodometric microgram determination of Mn(II) in aqueous media by an indirect chemical amplification reaction

A rapid, simple and highly sensitive iodometric amplification method is described for the determination of microgram amounts of Mn(II). The method is based on oxidation of Mn(II) with an excess of periodate in acetate buffer (pH 2.8-3.0), masking of the unreacted periodate with molybdate, and after addition of iodide, titration of the liberated iodine is with thiosulphate. The proposed method offers 20-fold amplification for Mn(II) and was found suitable for the determination of Mn(II) in the presence of permanganate ions. Mn(II) in tap water and an industrial waste water has been successfully determined by the proposed method.     

Solid phase extraction of trace metals in water and leafy vegetables using a resin functionalized with potassium 2-benzoylhydrazinecarbodithioate and determination by ICP–AES

A solid phase extraction method for the determination of Cu(II), Mn(II) and Zn(II) metal ions in natural water and leafy vegetable samples by ICP-AES was developed. The method was based on the sorption of metal ions onto Amberlite XAD-16 functionalized with a new chelating ligand potassium 2-benzoylhydrazinecarbodithioate (Amberlite XAD-16-PBHCD) and elution with nitric acid. The optimum experimental conditions for the quantitative sorption of the three metal ions, namely, effect of pH, sample volume, flow rate, concentration of eluent, sorption capacity, kinetics of sorption, and the effect of diverse ions on the sorption of analytes have been investigated. All the metal ions were quantitatively retained by the functionalized resin at pH 5.0 and sorbed metals could be eluted with 2.0?M HNO₃. The detection limits were 5.6, 4.5 and 1.8?µg?L^?1 for Cu(II), Mn(II) and Zn(II), respectively. The developed method was applied for the determination of Cu(II), Mn(II) and Zn(II) in water and leafy vegetable samples.     

Application of stripping voltammetry method for the analysis of available copper,zinc and manganese contents in soil samples

Determination of copper (Cu), zinc (Zn) and manganese (Mn) micronutrients in soil samples have been studied for an efficient fertiliser application. Plant-available micronutrients of soils were extracted with DTPA extraction procedure, then differential pulse stripping voltammetry (DPSV) and square wave stripping voltammetry (SWSV) methods were performed with inexpensive and disposable pencil graphite electrode for determination of Cu(II), Zn(II) and Mn(II). Parameters such as deposition potential, deposition time, pH and concentration of the supporting electrolyte were optimised for these ions. Under optimised conditions, the limits of detection were found as 0.01 mg L^?1 for Cu(II) and 0.02 mg L^?1 for Zn(II) and 0.25 mg L^?1 for Mn(II). Relative standard deviation (%RSD) was 6.80, 8.86 and 3.29 for Cu(II), Zn(II) and Mn(II), respectively. The experimental study was conducted using a flame atomic absorption spectroscopy. The described stripping voltammetry methods were successfully applied for the determination of Mn(II), Cu(II) and Zn(II) in soil samples.     

Ligandless-ultrasound-assisted emulsification microextraction followed by inductively coupled plasma-optical emission spectrometry for simultaneous determination of heavy metals in water samples

In this study, a simple and efficient method of ligandless-ultrasound-assisted emulsification microextraction (LL-USAEME) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) has been developed for simultaneous extraction, preconcentration and determination of manganese, cadmium, cobalt and nickel in water samples. In the proposed approach, tetrachloroethylene was selected as extraction solvent. The effect of important experimental factors such as volume of extraction solvent, pH, sonication time, salt concentration, and temperature was investigated by using a fractional factorial design (2^5?1) to identify important factors and their interactions. In the next step, a Box-Behnken design (BBD) was applied for optimisation of significant factors. The obtained optimal conditions were: 30?µL for extraction solvent, 12 for pH, 5?min for sonication time, and 5% w/v for salt concentration. The limits of detections (LODs) for Cd(II), Co(II), Mn(II) and Ni(II) were 0.20, 0.13, 0.21 and 0.28?µg?L^?1, respectively. Relative standard deviations (RSD, C?=?200.0?µg?L^?1, n?=?9) were between 3.4–7.5% and the calibration graphs were linear in the range of 0.25 to 1000.0?µg?L^?1 for Mn, 0.5–1000.0?µg?L^?1 for Co and Ni and 1.0–250.0?µg?L^?1 for Cd. The determination coefficients (R ²) of the calibration curves for the analytes were in the range of 0.993 to 0.999. The proposed method was validated by using two certified reference materials, and also the method was applied successfully for the determination of heavy metals in different real water samples.     

Effect of alkali cations,halides and thiocyanate on the Mn(Hg)/Mn(II) electrode reactions

The title subject has been studied by galvanostatic single-pulse, chronopotentiometric and equilibrium measurements on the Mn(Hg)/Mn(II) electrode (mainly saturated managanese amalgams) in one molar alkali chloride (LiCl, KCl and CsCl) and potassium iodide and thiocyanate solutions of pH 4 to 5 at 25°C. The Mn(Hg)/Mn(II) reactions are found to occur in two consecutive steps with monovalent ions as intermediate in all these solutions. The rates of both the ion-transfer step Mn(Hg)/Mn(I) and the electron-transfer step Mn(I)/Mn(II) appear independent of the cations Li⁺ and K⁺ and of the anions Cl^?, I^? and SCN^?, when differences in bulk activities of electroactive species are corrected for. The Cs⁺ ion, however, seems to retard the reactions more than expected from bulk activity changes, and this can be explained by Cs⁺ specific adsorption or by variations in the properties of the inner layer with the cation.     

Extractive-spectrophotometric determination of manganese(II) using 3-bromobenzohydroxamic acid as chelating agent

Summary A new extractive spectrophotometric method is described for determining trace amounts of Mn(II) based on its reaction at pH 10.2 with 3-bromobenzohydroxamic acid (3BrHA) and subsequent extraction into Adogen 464 in toluene. The apparent molar absorptivity of the 1:3:1 (Mn:3BrHA:Adogen 464) complex is 8.7×10³ l·mol⁻¹ cm⁻¹ at 450 nm. Beer's law is obeyed from 0.5 to 6.0 mg·1⁻¹ of Mn(II) in the aqueous phase with a C.V. of 1.2%. The detection limit is 0.18 mg·1⁻¹. The method has been successfully applied to the determination of manganese in standard steel samples, natural water samples and plant material.     

Solid Phase Extraction of Trace Metals in Seawater Using Morpholine Dithiocarbamate‐Loaded Amberlite XAD‐4 and Determination by ICP‐AES

Abstract

Application of morpholine dithiocarbamate (MDTC) coated Amberlite XAD‐4, for preconcentration of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II) by solid phase extraction and determination by inductively coupled plasma (ICP) atomic emission spectrometry (AES) was studied. The optimum pH values for quantitative sorption of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II), and Mn(II) were 6.5–8.0, 7.0–8.5, 6.0–8.5, 6.5–8.5, 7.5–9.0, and 8.0–8.5, respectively. The metals were desorbed with 2 mol L^?1. The t_1/2 values for sorption of metal ions were 2.6, 2.9, 2.5, 2.6, 3.0, and 3.8 min respectively for Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II). The effect of diverse ions on the determination of the previously named metals was studied. Simultaneous enrichment of the six metals was accomplished, and the method was applied for use in the determination of trace metal ions in seawater samples.     

Use of amberlite XAD-7HP for the separation of Mn(II) and Mn(VII) in waters

A simple method is proposed for the determination and speciation of Mn(II) and Mn(VII) in waters utilizing a macroporous resin, Amberlite XAD-7HP. The batch method was employed and flame atomic absorption spectrometry was used in all determinations. Amberlite XAD-7HP resin was shown to retain Mn(VII) between pH 4 and 12. If the solution contains only one of the species, either Mn(II) or Mn(VII), the resin behaves selectively depending on the pH of the solution. The elution from the sorbent was realized using K₂C₂O₄ in HNO₃. The efficiency of the method was checked via spike recovery experiments. The proposed method was successfully applied to industrial wastewater samples and quantitative recoveries (≥96.0%) confirmed the accuracy of the method.     

Stripping voltammetry method for determination of manganese as complex with oxine at the carbon paste electrode with and without modification with montmorillonite clay

Oxine (8-hydroxyquinoline) was used as an efficient and selective ligand for stripping voltammetry trace determination of Mn(II). A validated square-wave adsorptive cathodic stripping voltammetry method has been developed for determination of Mn(II) selectively as oxine complex using both the bare carbon paste electrode (CPE) and the modified CPE with 7 % (w/w) montmorillonite-Na clay. Modification of carbon paste with montmorillonite clay was found to greatly enhance its adsorption capacity. Limits of detection of 45 ng l^?1 (8.19?×?10^?10 mol L^?1) and 1.8 ng l^?1 (3.28?×?10^?11 mol L^?1) Mn(II) were achieved using the bare and modified CP electrodes, respectively. The achieved limits of detection of Mn(II) as oxine complex using the modified CPE are much sensitive than the detection limits obtained by most of the reported electrochemical methods. The developed stripping voltammetry method using both electrodes was successfully applied for trace determination of Mn(II) in various water samples without interferences from various organic and inorganic species.     

Catalytic determination of nanogram amounts of Mn(II) by the aerial oxidative coupling reaction of 3-methyl-2-benzothiazolinone hydrazone with N,N-dimethylaniline

Summary A new catalytic method for the determination of nanogram level of Mn(II) is developed, which is based on its catalytic effect on the aerial oxidative coupling reaction of 3-methyl-2-benzothiazolinone hydrazone (MBTH) withN, N-dimethylaniline (DMA) to form an indamine dye (_max=590 nm) in the presence of 1,10-phenanthroline (phen) as an activator. A detection limit of <0.05 ng Mn(II)/ml can be achieved and as low as 10^–9 M Mn(II) can easily be determined by measuring the absorbance of the dye at a fixed time (50 min at 30° C). The proposed method was successfully applied to the determination of manganese in natural waters by using 0.02–4 ml of water samples without preconcentration and separation.     

Substoichiometric isotope dilution analysis of iron in biological materials by the 8-quinolinol-extraction

A highly precise and accurate method for the determination of minor amounts of iron by substoichiometric isotope dilution analysis is described. The constant amount of Fe(III) is substoichiometrically extracted with 2·10⁻⁴M oxine in chloroform from the aqueous phase of pH 9.2–10.0 containing 6·10⁻³M tartrate. The interfering ions such as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), can be removed by the preliminary extraction of Fe(III) from 7.5M hydrochloric acid solutions into isopropyl ether. The present method has been applied to the determination of iron in biological standard reference materials, i.e., the NBS Spinach (SRM-1570) and the NIES Pepperbush (SRM No. 1), and the results obtained are 548±9 ppm (NBS certified value: 550±20 ppm) and 193±4 ppm, respectively.     

Radiochemical separation of Mn/II/ with 1,2,3-benzotriazole into 1-octanol employing solvent extraction technique

1,2,3-Benzotriazole /1,2,3-BT/ has been used for the radiochemical separation of Mn/II/ employing solvent extraction technique. Based on various parameters such as pH effect, time of equilibration and effect of various solvents, etc. the ideal conditions for the extraction of Mn/II/ was evaluated. The stoichiometry of the metal to reagent was determined by the substoichiometric extraction and slope-ratio method and found to be 12. The effect of anions on the extraction value of Mn/II/ revealed that a large number of anions do not interfere. Separation factors for various elements were also studied and the extraction found to be selective.     

Binding equilibrium study between Mn( Ⅱ ) and HSA or BSA

The binding of Mn( Ⅱ ) to human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by equilibrium dialysis at physiological pH (7. 43). The Scatchard analysis indicates that there are 1.8 and 1.9 strong binding sites of Mn( Ⅱ ) in HSA and BSA, respectively. The successive stability constants which are reported for the first time are obtained by non-linear least-squares methods fitting Bjerrum formula. For both Mn( Ⅱ )-HSA and Mn( Ⅱ )-BSA systems, the order of magnitude of K1 was found to be 104. The analyses of Hill plots and free energy coupling show that the positive cooperative effect was found in both Mn( Ⅱ )-HSA and Mn( Ⅱ )-BSA systems . The results of Mn ( Ⅱ ) competing with Cu ( Ⅱ ) 、 Zn(Ⅱ)、Cd( Ⅱ) or Ca( Ⅱ ) to bind to HSA or BSA further support the conjecture that there are two strong binding sites of Mn( Ⅱ) in both HSA and BSA. One is most probably located at the tripeptide segment of N- terminal sequence of HSA and BSA molecules involving four groups composed of n     

Triazine based Mn (II) and Mn (II)/Ln (III) complexes: Synthesis,characterization and catecholase activities

In the current work, two triazine‐based multidentate ligands (H₂L¹ and H₂L²) and their homo‐dinuclear Mn (II), mononuclear Ln (III) and hetero‐dinuclear Mn (II)/Ln (III) (Where Ln: Eu or La) complexes were synthesized and characterized by spectroscopic and analytical methods. Single crystals of a homo‐dinuclear Mn (II) complex {[Mn (HL¹)(CH₃OH)](ClO₄·CH₃OH}₂ ( 1 ) were obtained and the molecular structure was determined by X‐ray diffraction method. In the structure of the complex, each Mn (II) ion is seven‐coordinate and one of the phenolic oxygen bridges two Mn (II) centre forming a dimeric structure. The UV–Vis. and photoluminescence properties of synthesized ligands and their metal complexes were investigated in DMF solution and the compounds showed emission bands in the UV–Vis. region. The catecholase enzyme‐like activity of the complexes were studied for 3,5‐DTBC → 3,5‐DTBQ conversion in the presence of air oxygen. Homo‐dinuclear Mn (II) complexes ( 1 and 4 ) were found to efficiently catalyse 3,5‐DTBC → 3,5‐DTBQ conversion with the turnover numbers of 37.25 and 35.78 h^?1 (k_cat), respectively. Mononuclear Eu (III) and La (III) complexes did not show catecholase activity.     

Application of Multivariate Calibration Methods for the Simultaneous Multiwavelength Spectrophotometric Determination of Fe(II), Cu(II), Zn(II), and Mn(II) in Mixtures

Abstract

A sensitive method for the simultaneous spectrophotometric determination of Fe(II), Cu(II), Zn(II), and Mn(II) in mixtures has been developed with the aid of multivariate calibration methods, such as classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The method is based on the spectral differences of the analytes in their complexation reaction with 4‐(2‐pyridylazo)‐resorcinol (PAR) and the use of full spectra with wavelengths in the range of 300–600 nm. It was found that both the spectral positive and negative bands obtained against the PAR blank, are proportional to the concentration for each metal complex. The obtained linear calibration concentration ranges are 0.025–0.6, 0.05–0.8, 0.025–0.8, and 0.05–0.8 µg ml^?1 for Fe(II), Cu(II), Zn(II), and Mn(II), respectively, and the LODs for the four metal ions were found to be approximately 1–3×10^?2 µg ml^?1. The proposed method was applied to a verification set of synthetic mixtures of these four metal ions, with models built in three different wavelength ranges, i.e., 300–450, 450–600, and 300–600 nm, corresponding to the positive, negative bands and their combinations, respectively. It was shown that the PLS model for the 300–600 nm range gave the best results (RPE_T=6.9% and average recovery ～100%; cf. PCR: RPE_T=9.5% and average Recovery ～110%). This method was also successfully applied for the determination of the four metal ions in pharmaceutical preparations, chicken feedstuff, and water samples.     

Semi-online preconcentration of Cd, Mn and Pb on activated carbon for GFASS

This paper presents a method whereby trace elements in NH₄Cl-NH₃ medium are adsorbed on activated carbon in a micro-flow-injection (FI) semi-online sorbent extraction preconcentration system and then determined by graphite furnace atomic absorption spectrometry (GFAAS). The analytical performance of the proposed method for determining Cd, Mn and Pb was studied. A microcolumn packed with activated carbon was used as a preconcentration column (PCC). The metals to be determined were preconcentrated onto the column for 60 s and then rinsed with 0.02% (v/v) HNO₃ and eluted with 30 μl of 2 mol l⁻¹ HNO₃. Compared with the direct injection of 30 μl of aqueous sample solution, enrichment factor of 32, 26, and 21 and detection limits (3σ) of 0.4, 4.7, and 7.5 ng l⁻¹ for Cd, Mn and Pb, respectively, were obtained with 60 s sample loading at 3.0 ml min⁻¹ for sorbent extraction, 30 μl of eluate injection, and peak area measurement. The precisions (RSD, n=6) were 2.8% at the 0.05 μg l⁻¹ level for Cd, 3.0% at the 0.3 μg l⁻¹ level for Mn, and 3.1% at the 0.5 μg l⁻¹ level for Pb. The experimental results indicate that the procedure can eliminate the fundamental interferences caused by alkali and alkaline earth metals and the application of it to the determination of Cd, Mn and Pb in some water samples is successful.