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1.
《Electroanalysis》2006,18(8):823-829
Bismuth coated glassy carbon electrodes have been applied to the square‐wave anodic stripping voltammetry (SWASV) of trace concentrations of tin. Optimization of Bismuth Film Electrode (BFE) performance was conducted after initial comparison with the more traditional mercury electrode. Simultaneous deposition of tin and bismuth at ?1.3 V for 2 minutes in a supporting electrolyte of 2.5 M sodium bromide utilizing a square‐wave stripping step, allowed analysis of tin at the μg L?1 level. Parameters, such as deposition potential and time, bismuth concentration, square‐waveform settings including amplitude, step height and frequency were studied and optimized. The dependence of stripping current on deposition time indicates that using longer deposition time should facilitate sub μg L?1 analysis. Tin was analyzed simultaneously with cadmium and either indium or thallium; Where as lead and copper were not resolved from the stripping peaks of tin and bismuth respectively. Finally, the method was applied to the analysis of tin in fruit juice.  相似文献   

2.
An adsorptive differential pulse stripping method for the simultaneous determination of lead and tin is proposed. The procedure involves an adsorptive accumulation of lead and tin on a hanging mercury drop electrode (HMDE), followed by oxidation of adsorbed lead and tin by voltammetric scan using differential pulse modulation. The optimum experimental conditions are: 0.2 mol L?1 HNO3, accumulation potential of ?900 mV versus Ag/AgCl, accumulation time of 200 s, scan rate of 20 mV s?1 and pulse height of 80 mV. Lead and tin peak currents were observed in the same potential region at about ?400 mV. The simultaneous determination of lead and tin by using voltammetry is a difficult problem in analytical chemistry, due to voltammogram interferences. The resolution of a mixture of lead and tin by the application of orthogonal signal correction‐partial least squares (OSC‐PLS) was performed. The linear dynamic ranges were 0.003‐0.35 and 0.008‐0.50 μg mL?1 and detection limits were land 3 ng mL?1 for lead and tin, respectively. The RMSEP for lead and tin with OSC and without OSC were 2.8737, 6.0557 and 8.0941, 9.5151, respectively. The capability of the method for the analysis of real samples was evaluated by the determination of lead and tin in water samples with satisfactory results.  相似文献   

3.
With a view to energetic and (opto)electronic applications, tin (IV) oxide (SnO2) nanoparticles have been successfully prepared at the nanoscale by a templating approach based on the use of zinc (II) oxide (ZnO) as template. The procedure consisted in preparing a mixture of tin precursor and template, subsequently calcined at 650 °C under air to lead to the formation of a SnO2/ZnO composite material. Finally, the material was washed with an alkali solution to remove the template. The template/tin precursor mass ratio was varied in order to tailor the tin (IV) oxide material, especially with a view to main particle size. The resulting SnO2 nanomaterials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption and electron microscopy. The tin (IV) oxide nanomaterial exhibited enhanced textural and physical surface properties (particle size, surface area, pore size) correlated to an increasing template/tin precursor mass ratio. For instance, from optimized experimental conditions, the specific surface area and pore volume were heightened twofold, reaching values of 49 m2/g and 0.32 cm3/g, respectively.  相似文献   

4.
《Electroanalysis》2006,18(10):976-980
A sensitive and selective procedure for the determination of trace tin at a carbon paste electrode was described. Each measurement cycle consisted of three steps: accumulation, reduction and stripping. The tin complex with bromopyrogallol red (BPR) was accumulated on the electrode surface in 0.10 mol/L acetate buffer (pH 4.5). After electrochemical reduction of Sn(II) had been carried out, the reoxidation wave of Sn(0) appeared at ?0.69 V (vs. SCE) on scanning the potential in the positive direction in 4.0 mol/L HCl. For a preconcentration time of 2 min, the detection limit was 0.06 μg/L (5×10?10 mol/L ) and the linear range was from 0.1 to 50 μg/L. The proposed method was applied to the determination of tin in canned food and waste water samples with satisfactory results.  相似文献   

5.
The influence of catechol, gallic acid and tiron on the voltammetric behaviour of tin(IV) in the presence of lead(II) and cadmium(II) was investigated at hanging drop and mercury film electrodes in perchloric acid, oxalic acid and formate supporting electrolytes. Under cyclic conditions, well separated peaks of tin, lead and cadmium are obtained in oxalic acid and formate solutions containing gallic acid or catechol; tiron suppresses the tin peaks significantly. The efficiency of the deposition of tin in the presence of catechol or gallic acid is less than that of lead, particularly at long deposition time. The best separation of the stripping peaks of tin, lead and cadmium is obtained in oxalic acid solution containing gallic acid or catechol. In perchloric acid solution containing gallic acid or catechol the second peak corresponding to tin oxidation is useful for determinations of tin in the presence of lead. Tin(IV) at the 10-8 mol l-1 level can be detemined in various salt solutions and in water samples in the presence of five-fold amounts of lead and cadmium.  相似文献   

6.
We report on a glassy carbon electrode (GCE) modified with a lead ionophore and multiwalled carbon nanotubes. It can be applied to square wave anodic stripping voltammetric determination of Pb(II) ion after preconcentration of Pb(II) at ?1.0?V (vs. SCE) for 300?s in pH?4.5 acetate buffer containing 400?μg?L?1 of Bi(III). The ionophore-MWCNTs film on the GCE possesses strong and highly selective affinity for Pb(II) as confirmed by quartz crystal microbalance experiments. Under the optimum conditions, a linear response was observed for Pb(II) ion in the range from 0.3 to 50?μg?L?1. The limit of detection (at S/N?=?3) is 0.1?μg?L?1. The method was applied to the determination of Pb(II) in water samples with acceptable recovery.
Figure
A glassy carbon electrode modified with a lead ionophore and multiwalled carbon nanotubes is successfully applied to sensitive and selective square wave anodic stripping voltammetric determination of Pb(II) ion after preconcentration of Pb(II) at ?1.0?V (vs. SCE) in pH?4.5 solutions containing 400?μg?L?1 of Bi(III).  相似文献   

7.
We report on an anodic stripping voltammetric method for the determination of tin using a glassy carbon electrode modified with bismuth and poly(bromophenol blue). After an accumulation time of 60?s at ?1.20?V (vs. SCE), the response of the electrode to tin in 1.0?M HCl is linear in the concentration ranges from 20 nM to 1.0?μM, and from 1.0?μM to 20?μM, with a detection limit of 7.0 nM (at an SNR of 3) and with relative standard deviations in the order of 3.0–3.8%. The method was validated by comparing the results with those obtained by AAS and successfully applied to the determination of tin in canned food.
Figure
Differential pulse stripping voltammetric responses of Sn2+ at Bi/Poly(BPB)/GCE in 1.0 M HCl . Sn2+ concentration (μM): 0.020, 0.10, 0.30, 0.50, 0.70, 1.0, 3.0, 5.0, 7.0, 10.0 and 20.0. Inset: Differential pulse stripping voltammograms of circle portion at low Sn2+ concentration are zoomed in.  相似文献   

8.
The influence of cetyltrimethylammonium bromide (CTAB) on the simultaneous determination of tin(IV) and lead(II) by anodic stripping voltammetry at a hanging mercury drop electrode (HMDE) in a 0.1 M hydrochloric acid—0.1 M oxalic acid medium was studied using d.c. and a.c. stripping. In the presence of CTAB, tin and lead show voltammetric peaks separated by 100 mV, the sensitivity depending on the concentration of CTAB. The best conditions for the simultaneous determination of both elements (2 × 10-3 M) were found. A method is proposed for the determination of tin in the presence of lead and three procedures are given for the determination of lead in the presence of tin.  相似文献   

9.
Isomeric mixtures of compounds MenM(CH?CHMe)4?n (M=Si, Pb; n=0?3) have been prepared and studied, as well as pure Me3M(CMe?CH2) and mixtures containing propenyl isopropenyl residues bonded to silicon and lead. 1H, 13C, 29Si and 207Pb NMR data are presented; as previously observed for the corresponding tin compounds, the 29Si and 207Pb shifts for the Me3MC3H5 isomers can be used to calculate the shifts expected for the other isomers; while for lead the agreement is good, calculated and observed values for silicon diverge with decreasing n due, at least in part, to steric factors.  相似文献   

10.
Stripping voltammetry with collection at a rotating mercury-film disc-ring electrode is applied for the determination of tin in glassy-carbon methanolic hydrobromic acid solution. The limit of determination is 20 nM (2.3 ng ml-1). Lead does not interfere when the lead/tin concentration ratio is less than ca. 500.  相似文献   

11.
Zusammenfassung Die invers-voltammetrisehe Bestimmung von Zinn kann bei einem 105fachen Bleiüberschuß nach der Oxydation des Zinn-Hämateinkomplexes an einer Kohlepaste-Elektrode durchgeführt werden. Dazu wird die bleihaltige salzsaure Zinnlösung mit einer Lösung von Hämatein in Dioxan versetzt und nach einer Vorelektrolyse bei offenem Stromkreis das Voltammogramm zwischen ±0,0 und +1,0 V (GSE) aufgenommen. Das Strommaximum des Oxydationspeaks liegt bei +0,72 V. Die Peakhöhe ist bei einem 104- bis 105fachen Bleiüberschuß der Zinnkonzentration zwischen 10 und 100 ng/ml proportional. Das Bestimmungsverfahren wird an einem Bleistandard mit einem Zinngehalt von 0,005% erprobt. Die relative Standardabweichung der Analysenergebnisse beträgt 4,6%. Die Bestimmung kann auch in Gegenwart eines 105fachen Überschusses von Zink vorgenommen werden. Fe(III), Cu(II), Sb(III) und Sb(V) stören, wenn sie in zu hoher Konzentration vorhegen. — Zur Bestimmung von Blei in Gegenwart von Zinn wird Pb(II) zu Pb(IV) oxydiert, das als Bleidioxid während der Vorelektrolyse abgeschieden und durch kathodischen Spannungsablauf wieder gelöst wird. Die Bestimmung kann in Gegenwart eines 100fachen Zinnüberschusses erfolgen, wenn die Zusatzmethode angewandt wird. — Es werden einige von der üblichen invers-voltammetrischen Praxis abweichenden Besonderheiten und die Reaktionsfolgen beider Bestimmungsverfahren diskutiert.
Inverse-voltammetric determination of tin and lead in the presence of each other at the carbon-paste electrode
The inverse-voltammetric determination of tin can be carried out in the presence of a 105-fold excess of lead by oxydation of the tin hematein complex on the carbon-paste electrode. For that purpose, to the solution containing tin and lead a solution of hematein in dioxane is added and the voltammogram is recorded between 0.0 and +1.0 V (SSE). Pre-electrolysis is performed at ±0.0 V without polarizing the electrode. The peak potential of the oxydation signal appears near +0.72 V. The peak height is proportional to the concentration of tin in the range between 10 and 100 ng/ml. The determination is not disturbed by a 104- to 105-fold excess of lead and zinc. The method is applied to a standard sample of lead containing 0.005% tin. The standard deviation was 4.6%. Fe(III), Cu(II), Sb(III) and Sb(V) interfere if these elements are present in too high a concentration. — In the determination of lead in the presence of tin, Pb(II) is oxidized forming PbO2 which is deposited on the surface of the electrode and redissolved by subsequent cathodic voltage scanning. The determination of lead can be carried out by the addition technique in the presence of a 100-fold excess of tin.— The order of the reactions and some further details of both methods are discussed.


Vorgetragen auf der GDCh-Hauptversammlung in Hamburg im September 1969.  相似文献   

12.
A new glassy carbon electrode modified with novel calix[4]‐arene derivative was prepared and then applied to the selective recognition of lead ion in aqueous media by cyclic and square wave voltammetry. A new anodic stripping peak at ? 0.92 V (vs. Ag/Ag+) in square wave voltammogram can be obtained by scanning the potential from ? 1.5 to ? 0.6 V, of which the peak current is proportional to the concentration of Pb2+. The modified electrode in 0.1 mol/L HNO3 solution showed a linear voltammetric response in the range of 2.0 × 10–8–1.0 × 10–6 mol/L and a detection limit of 6.1 × 10–9 mol/L. In the modified glassy carbon electrode no significant interference occurred from alkali, alkaline and transition metal ions except Hg2+, Ag+ and Cu2+ ions, which can be eliminated by the addition of KSCN. The proposed method was successfully applied to determine lead in aqueous samples.  相似文献   

13.
Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn2+ to Sn4+. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI3) films: hydrazinium tin iodide (HASnI3) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI2), and then transformed into MASnI3 via a cation displacement approach. With the two‐step process, a dense and uniform MASnI3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI3 as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility.  相似文献   

14.
A new tin(IV) complex, (C13H10NO)[SnCl4(C9H6NO)]·2CH3OH, was prepared in a facile process and characterized by 1H, 13C, and 119Sn NMR, IR, and UV spectroscopy in addition to single-crystal X-ray diffraction analysis. Current–voltage (I–V) characteristics, photoluminescence (PL), and electroluminescence (EL) properties of the complex have been investigated and an application of the prepared complex in fabrication of an organic light-emitting diode has been demonstrated. The EL of the compound exhibits blue–green emission at 494?nm. Tin(IV) oxide core that resulted from direct thermal decomposition of the complex at 450?°C in air was characterized by X-ray powder diffraction and scanning electron microscopy; then, the PL property was investigated and compared with the PL of the complex. The tin(IV) oxide core showed a band gap of ~3.81?eV determined from the UV/visible absorption spectrum. The tin oxide core showed stable PL with one emission peak centered at 581?nm.  相似文献   

15.
Zusammenfassung Es wird über eine photometrische Methode berichtet, die es gestattet, Spuren von Zinn in Blei und antimonhaltigen Bleilegierungen schnell und genau zu bestimmen. Das Blei wird als Bleichlorid abgetrennt und das Filtrat fast zur Trockne eingedampft. Der Bückstand wird mit einer Lösung aus Natriumjodid (6,5 M) und Perchlorsäure (1 M) aufgenommen, aus der das Zinn selektiv mit Benzol extrahiert wird. Die photometrische Zinnbestimmung erfolgt mit dem sehr empfindlichen und fast spezifischen Reagens Hämatein. Nach dieser Methode können bis zu 2 · 10–4% Sn in Blei bestimmt werden. Die Bestimmungsgrenze bei antimonhaltigen Legierungen ist abhängig von dem Antimongehalt. Bei einer Zinnkonzentration von 1,7 · 10–2% in einer Bleilegierung mit 7% Sb beträgt die relative Standardabweichung ± 3%.
Photometric determination of tin in lead and lead alloys containing antimony
Lead is separated as lead chloride and the filtrate is evaporated almost to dryness. The residue is dissolved in a solution of sodium iodide (6,5 M) and perchloric acid (1 M), and the tin is quantitatively extracted with benzene. For its photometric determination the very sensitive and highly selective reagent haematein is used. Up to 2×10–4% tin in lead could be determined. The estimation limit in antimonial lead alloy depends upon the antimony content. With a tin concentration of 1.7×10–2% in an antimonial lead alloy containing 7% Sb, the relative standard deviation corresponds to ± 3%.
  相似文献   

16.
A novel sulfhydryl-modified covalent organic framework was designed for the selective determination of lead(II) using square wave anodic stripping voltammetry. The introduction of sulfhydryl groups enhanced the selectivity and sensitivity of the covalent organic framework for analytes. The sulfhydryl-modified covalent organic framework was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Under the optimized conditions, a sulfhydryl-modified covalent organic framework/gold electrode was successfully used for the determination of lead(II) in water samples. The newly developed square wave anodic stripping voltammetry method exhibited wide linearity (0.05 to 20?ng mL?1, r?=?0.991), a low limit of detection (0.015?ng mL?1) and good precision, with a relative standard deviation values <5.1%. The limit of detection was lower than 10?ng mL?1, the level of lead(II) in drinking water permitted by the World Health Organization. The recoveries of three spiked samples ranged from 90.0% to 104.0%, with relative standard deviations <4.9%. Satisfactory reproducibility and good repeatability demonstrated that the newly developed method is very suitable for the detection of lead(II) in real water samples, with significant advantages over existing methods.  相似文献   

17.
Diphenylglyoxal bis(2-hydroxybenzoylhydrazone) has been used as a sensitive reagent for the spectrophotometric determination of tin. This reagent forms an orange-yellow complex with stannous ion at pH 3.5–7.0 (λmax = 455 nm, ? = 2.25 × 104 liter mol?1/cm?1 while no reaction is observed with quadrivalent tin. The colored complex extracted into isobutyl methyl ketone has been used for the spectrophotometric determination of trace amounts of tin(II). The molar absorption in the organic solvent is 3.54 × 104 liter mol?1 cm?1 and the compound shows its maximum absorbance at 455 nm. The interferences of foreign ions have been determined.  相似文献   

18.
A complete series of diphenyl and mixed methyl/chlorine/bromine/iodinephenyl substituted oxadithia- and trithiastannocanes has been prepared by reactions between the respective disodium dithiolates and tin dihalides. The 13C NMR chemical shifts of these compounds and the coupling constants J(119Sn13C) are dependent upon the magnetic anisotropy of the substituents and the bond angles at the tin atom. The crystal structure of 2,2-diphenyl-1,3,6-trithia-2-stannocane has been determined and refined to R = 0.039. The environment of Sn is a monocapped tetrahedron (transannular distance Sn?S 324.6(1) pm). This type of coordination, intermediate between a tetrahedron and a trigonal bipyramid, is discussed quantitatively and compared with a series of analogous compounds. The eight-membered ring has the boat-chair conformation.  相似文献   

19.
Trace element characterization of bullet lead by instrumental neutron activation analysis (INAA) is hampered by the high spectral background due to antimony, normally present in high concentration in bullet lead. Tin is indicated to be a very useful element for characterization purposes. Beta-active121Sn is a suitable nuclide for quantitation of tin provided it is separated in high radiochemical purity. A radiochemical procedure capable of determining tin down to 10 ppm in bullet lead, a sequential procedure for its determination along with copper, arsenic and antimony and the application of this procedure for the determination of the contents of these elements in various bullet leads are described. This method has been applied to a “Rhinoceros shoot-out” case, referred to our laboratory.  相似文献   

20.
Shams E  Abdollahi H  Yekehtaz M  Hajian R 《Talanta》2004,63(2):359-364
The applicability of H-point standard addition method (HPSAM) to the resolving of overlapping differential pulse anodic stripping voltammetric peaks corresponding to the oxidation of lead and tin is verified. The results show that the H-point standard addition method is suitable for the simultaneous determination of lead and tin in aqueous media. The results of applying the H-point standard addition method showed that Sn2+ and Pb2+ could be determined simultaneously with the concentration ratios of Sn2+ to Pb2+ varying from 1:5 to 10:1 in the mixed sample. The proposed method has been successfully applied to the simultaneous determination of lead in the presence of tin in some synthetic samples. Moreover, the applicability of the method was demonstrated by the recovery of lead in a canned soft drink sample.  相似文献   

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