共查询到20条相似文献,搜索用时 31 毫秒
1.
Deepti S. Gholap Johannes T. van Elteren Roel Evens Colin Janssen Inge Lindemann Frank Vanhaecke 《Analytica chimica acta》2010,664(1):19-239
Visualization of elemental distributions in thin sections of biological tissue is gaining importance in many disciplines of biological and medical research. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and scanning micro-X-ray fluorescence spectrometry (micro-XRF) are two widely used microanalytical techniques for elemental mapping. This article compares the capabilities of the two techniques for imaging the distribution of selected elements in the model organism Daphnia magna in terms of detection power and spatial resolution. Sections with a thickness of 10 and 20 μm of the fresh water crustacean Daphnia magna were subjected to LA-ICP-MS and micro-XRF analysis. The elemental distributions obtained for Ca, P, S and Zn allow element-to-tissue correlation. LA-ICP-MS and micro-XRF offer similar limits of detection for the elements Ca and P and thus, allow a cross-validation of the imaging results. LA-ICP-MS was particularly sensitive for determining Zn (LOD 20 μg g−1, 15 μm spot size) in Daphnia magna, while the detection power of micro-XRF was insufficient in this context. However, LA-ICP-MS was inadequate for the measurement of the S distributions, which could be better visualized with micro-XRF (LOD 160 μg g−1, 5 s live time). Both techniques are thus complementary in providing an exhaustive chemical profiling of tissue samples. 相似文献
2.
Tianxi Sun Xunliang Ding Zhiguo Liu Guanghua Zhu Yude Li Xiangjun Wei Dongliang Chen Qing Xu Quanru Liu Yuying Huang Xiaoyan Lin Hongbo Sun 《Spectrochimica Acta Part B: Atomic Spectroscopy》2008
A new confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) facility based on polycapillary X-ray optics in the detection channel and Kirkpatrick–Baez (KB) mirrors in the excitation channel is designed. The lateral resolution (lx, ly) of this confocal three-dimensional micro-X-ray fluorescence facility is 76.3(lx) and 53.4(ly) µm respectively, and its depth resolution dz is 77.1 μm at θ = 90°. A plant sample (twig of B. microphylla) and airborne particles are analyzed. 相似文献
3.
In this paper a novel solid phase extraction method to determine Co(II) and Ni(II) using silica gel-polyethylene glycol (Silica-PEG) as a new adsorbent is described. The method is based on the adsorption of cobalt and nickel ions in alkaline media on polyethylene glycol-silica gel in a mini-column, elution with nitric acid and determination by flame atomic absorption spectrometry. The adsorption conditions such as NaOH concentration, sample volume and amount of adsorbent were optimized in order to achieve highest sensitivity. The calibration graph was linear in the range of 0.5-200.0 ng mL−1 for Co(II) and 2.0-100.0 ng mL−1 for Ni(II) in the initial solution. The limit of detection based on 3Sb was 0.37 ng mL−1 for Co(II) and 0.71 ng mL−1 for Ni(II). The relative standard deviations (R.S.D.) for ten replicate measurements of 40 ng mL−1 of Co(II), and Ni(II) were 3.24 and 3.13%, respectively. The method was applied to determine Co(II) and Ni(II) in black tea, rice flour, sesame seeds, tap water and river water samples. 相似文献
4.
Thin films of bis(dimethylglyoximato)palladium(II) complex of polycrystalline structure were prepared by sublimation in a vacuum at 140 °C, on glass and p-Si substrates. The films were characterised by spectral optical absorption, energy dispersion X-ray fluorescence (EDXRF), and X-ray diffraction (XRD) methods. After characterisation, metal-insulator (complex)-semiconductor MIS devices were fabricated to measure the frequency dependence of ac-conductivity in a range of 5-100 kHz. Data of ac-measurements follow the correlated barrier-hopping CBH model, from which one of the fundamental absorption peaks, the minimum hopping distance, and other parameters of the CBH model were determined, connecting and relating the optical, structural, and electrical measurements. The dielectric properties of the complex were studied through Debye model, from which the relaxation time for the dipoles (2.45 × 10−6 s) and the molecular dipole moment (3.63 × 10−30 C m ) were determined. 相似文献
5.
Victor N. Khrustalev Ivan A. Portnyagin Irina V. Borisova Yuri A. Ustynyuk Valery Lunin 《Journal of organometallic chemistry》2005,690(5):1172-1177
New stable heteroleptic germanium(II) and tin(II) compounds [(SiMe3)2N-E14-OCH2CH2NMe2]n (E14 = Ge, n = 1 (1), Sn, n = 2 (2)) have been synthesized and their crystal structures have been determined by X-ray diffraction analysis. While compound 1 is monomer stabilized by intramolecular Ge ← N coordination, compound 2 is associated to dimer via intermolecular dative Sn ← O interactions. 相似文献
6.
Silica gel-bound amines phase modified with p-dimethylaminobenzaldehyde (p-DMABD) was prepared based on chemical immobilization technique. The product (SG-p-DMABD) was used as an adsorbent for the solid-phase extraction (SPE) Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The uptake behaviors of SG-p-DMABD for extracting these metal ions were studied using batch and column procedures. For the batch method, the optimum pH range for Cr(III) and Ni(II) extraction was ≥ 3, for Cu(II), Pb(II) and Zn(II) extraction it was ≥ 4. For simultaneous enrichment and determination of all the metals on the newly designed adsorbent, the pH value if 4.0 was selected. All the metal ions can be desorbed with 2.0 mL of 0.5 mol L− 1 of HCl. The results indicate that SG-p-DMABD has rapid adsorption kinetics using the batch method. The adsorption capacity for these metal ions is in the range of 0.40-1.15 mmol g− 1, with a high enrichment factor of 125. The presence of commonly coexisting ions does not affect the sorption capacities. The detection limits of the method were found to be 1.10, 0.69, 0.99, 1.10 and 6.50 μg L− 1 for Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The relative standard deviation (RSD) of the method under optimum conditions was 5.0% (n = 8) for all metal ions. The method was applied to the preconcentration of Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) from the certified reference material (GBW 08301, river sediment) and water samples with satisfactory results. 相似文献
7.
NiO nanoparticles with an average size of 15 nm were easily prepared via the thermal decomposition of the tris(ethylenediamine)Ni(II) nitrate complex [Ni(en)3](NO3)2 as a new precursor at low temperature, and the nanoparticles were characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV-Vis spectroscopy, BET specific surface area measurement, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and magnetic measurements. The magnetic measurements confirm that the product shows a ferromagnetic behavior at room temperature, which may be ascribed to a size confinement effect. The NiO nanoparticles prepared by this method could be an appropriate photocatalytic material due to a strong absorption band at 325 nm. This method is simple, fast, safe, low-cost and also suitable for industrial production of high purity NiO nanoparticles for applied purposes. 相似文献
8.
Lin Cheng Xunliang DingZhiguo Liu Qiuli PanXuelian Chu 《Spectrochimica Acta Part B: Atomic Spectroscopy》2007
A new micro-X-ray fluorescence (micro-XRF) system based on rotating anode X-ray generator and polycapillary X-ray optics has been set up in XOL Lab, BNU, China, in order to be used for analysis of archaeological objects. The polycapillary X-ray optics used here can focus the primary X-ray beam down to tens of micrometers in diameter that allows for non-destructive and local analysis of sub-mm samples with minor/trace level sensitivity. The analytical characteristics and potential of this micro-XRF system in archaeological research are discussed. Some described uses of this instrument include studying Chinese ancient porcelain. 相似文献
9.
Use of 1-(2-pyridylazo)-2-naphthol as the post column reagent for ion exchange chromatography of heavy metals in environmental samples 总被引:1,自引:0,他引:1
Supalax Srijaranai Wijitra Autsawaputtanakul Tipwan Khameng Richard L. Deming 《Microchemical Journal》2011,99(1):152-158
Ion exchange chromatography (IEC) using a bi-functional column (quaternary ammonium and sulfonate groups), followed by post-column reaction (PCR) with 1-(2-pyridylazo)-2-naphthol (PAN), was used to separate and quantitate Cu(II), Ni(II), Zn(II), Co(II), Cd(II), Mn(II) and Hg(II) at low concentration levels. IEC-PCR separation was achieved within 14 min using the mobile phase containing 3 mmol L− 1 2,6-pyridinedicarboxylic acid (PDCA) and 3 mmol L− 1 oxalate at pH 12.5. Effects of pH as well as PAN, detergent and chloride ion concentrations during post-column reaction on detector response were examined. Detection limits were less than 4.5 μg L− 1 for all metals except Hg(II) (19 μg L− 1) using spectrophotometric measurements at 550 nm. Analytical validations showed good linearity for detection up to 6.0 mg L− 1, with R2 higher than 0.99. Precisions based on retention time evaluation for intra-day and inter-day measurements with the relative standard deviation (RSD) were less than 2.9% and 3.6%, respectively. The method gave good accuracy with the recoveries ranged from 80.5 to 105% for all metal ions studied. The proposed method was applied to the analysis of metal ions in environmental samples (leachate, soil and sediment) in Northeastern Thailand. The results were in good agreement with atomic spectroscopic measurements on the same samples. 相似文献
10.
Vladimir V. Bon Svetlana I. Orysyk Vasilii I. Pekhnyo Viktor V. Orysyk Sergei V. Volkov 《Polyhedron》2007
The present paper describes the synthesis and spectral properties of Rh(III) and Pd(II) coordination compounds with N-(pyridine-2-yl)morpholine-4-carbothioamide (PMCTA). The compounds have the general composition [RhL2Cl2]Cl · C2H5OH (1), [PdL2]Cl2 (2), [PdL2](ClO4)2 · 2C3H6O (2a), [PdLCl2] · 2H2O (3). All complexes were characterized by elemental analysis, IR, 1H NMR, 13C NMR, XPS and UV–Vis spectra. It has been shown that PMCTA behaves as a bidentate (N,S)-ligand, forming six membered metallocycles and coordinating to the metal ion through the carbothioamide sulfur atom and the pyridine nitrogen atom. The UV–Vis spectra suggest that the Pd(II) complexes are square planar, while the Rh(III) complex has an octahedral geometry. The molecular structure of the Pd(II) complex with PMCTA (M:L = 1:2) was determined by single-crystal X-ray diffraction. 相似文献
11.
In the present work, the applicability of thin mercury film on a rotating disk electrode (TMF-RDE), to assess the free metal ion concentration by the absence of gradients and Nernstian equilibrium stripping (AGNES), is evaluated. The thickness of the mercury film and several AGNES parameters has been optimized. A nominal 16 nm film is chosen due to the higher signal (faradaic current) relative to the value of the noise (capacitive current). Due to the smaller volume to area ratio, the deposition time needed to reach a certain preconcentration factor (Y) is much shorter than in larger electrodes, like the HMDE. The limit of detection (3σ) for lead(II) is 7.4 × 10−9 M and 7.2 × 10−8 M for a Y of 5000 (deposition time of 150 s) and 1000 (deposition time of 100 s), respectively. A specific mathematical treatment is developed in order to subtract a corrected blank taking into account the degradation of the thin film (presumably, falling down of drops). The couple TMF-RDE/AGNES is successfully applied for speciation purposes in the systems Pb(II)-latex nanospheres and Pb(II)-IDA (iminodiacetic acid), where the stability constants calculated for both systems agree with values reported in the literature. 相似文献
12.
The synthesis of two ligands, L1 and L2, each containing two 2-oxy-1,10-phenanthroline moieties attached to the same phosphorus atom of a substituted cyclotriphosphazene ring via an oxy-bridge, but differing in substitution on the biphenyl capping groups, is described. The single-crystal X-ray structure of L1 · 2CH2Cl2 shows an ordered structure in the lattice with channels, containing dichloromethane molecules, running parallel to the a-axis. The reactions of L1 and L2 with [Cu(MeCN)4](PF6) afford the dimetallic copper(I) derivatives, [(CuL1)2] (PF6)2 · CH2Cl2 and [(CuL2)2](PF6)2. The single-crystal X-ray structure of the former complex shows that the L1 ligands of the cation [(CuL1)2]2+ act as a bridges coordinating to the two copper(I) centres in a helical fashion. The copper atoms have distorted tetrahedral geometries with the interligand dihedral angle being 85°. With copper(II) chloride and copper(II) perchlorate, the monomeric copper(II) complexes, [CuL1Cl]Cl · 2CH2Cl2, [CuL2Cl]Cl · CH2Cl2, [CuL1(OMe)]PF6 · 2H2O, [CuL2(OMe)]PF6 · 2H2O, [CuL1(OH2)](ClO4)2 and [CuL2(OH2)](ClO4)2 · H2O are obtained. The single-crystal X-ray structure of [CuL1Cl]Cl · 2CH2Cl2 shows the copper to be in a square-base pyramidal distorted trigonal-bipyramidal (SBPDTB) environment (τ = 0.57) with L1 acting as a κ4N donor, coordinating via the four nitrogen atoms of the two tethered 1,10-phenanthrolines. In CH3CN, this complex undergoes hydrolysis via the presence of adventitious water losing one oxyphenanthroline arm to form the centrosymmetric dimetallic species, [(CuL3Cl)2] · 4CH3CN · 3H2O (L3 = [N3P3(biph)2(ophen)O]− where biph = 2,2′-dioxybiphenyl and O replaces an oxyphenanthroline and is attached to the phosphorus of the phosphazene ring). The two monomeric units, which are linked by bridging chlorine atoms, have a distorted square-based pyramidal geometry about the copper with the basal plane made by the ‘ON2Cl’ ligand set. Spectroscopic (mass spectral, electronic and ESR) and magnetic moment data for the complexes are discussed. 相似文献
13.
Two mononuclear Co(II) complexes based upon 2-(1H-benzimidazol-2-yl)phenol, abbreviation Hsalbim ligand, have been prepared and studied. The structure of Hsalbim and [Co(salbim)2] have been confirmed by X-ray structure analysis. The second cobalt(II) complex matches the formula [Co(salbim)2]·(Hsalbim)·MeOH assuming a co-crystallization of one neutral ligand. The electronic spectra are consistent with the tetrahedral pattern. Magnetic susceptibility measurements down to T = 2 K along with the magnetization data until B = 7 T show that the Co(II) complexes are high-spin with a considerable zero-field splitting of the 4B1(D2d) term: D/hc = 67 and 55 cm−1, respectively. 相似文献
14.
This paper reports the first use of a polymer inclusion membrane (PIM) for on-line separation in flow injection analysis (FIA) involving simultaneous extraction and back-extraction. The FIA system containing the PIM separation module was used for the determination of Zn(II) in aqueous samples in the presence of Mg(II), Ca(II), Cd(II), Co(II), Ni(II), Cu(II), and Fe(III). The Fe(III) and Cu(II) interferences were eliminated by off-line precipitation with phosphate and on-line complexation with chloride, respectively. The concentration of Zn(II) was determined spectrophotometrically using 4-(2-pyridylazo) resorcinol (PAR). The optimal composition of the PIM consisted of 40% (m/m) di(2-ethlyhexyl) phosphoric acid (D2EHPA) as carrier, 10% (m/m) dioctyl phthalate (DOP) as plasticizer and 50% (m/m) poly(vinyl chloride) (PVC) as the base polymer. The optimized FIA system was characterized by a linear calibration curve in the range from 1.0 to 30.0 mg L−1 Zn(II), a detection limit of 0.05 mg L−1 and a relative standard deviation of 3.4% with a sampling rate of 4 h−1. Reproducible results were obtained for 20 replicate injections over a 5 h period which demonstrated a good membrane stability. The FIA system was applied to the determination of Zn(II) in pharmaceuticals and samples from the galvanizing industry and very good agreement with atomic absorption spectrometry was obtained. 相似文献
15.
Leelasattarathkul T Liawruangrath S Rayanakorn M Oungpipat W Liawruangrath B 《Talanta》2006,70(3):656-660
A sequential injection analysis (SIA) using lab-on-valve with air segmentation and spectrophotometric detection was designed for copper(II) determination. It is based on the reaction of copper(II) and 2-carboxy-2′-hydroxy-5′-sulfoformazyl benzene (Zincon) in a weak alkaline solution between the air zones. Beer's Law was obeyed over the range of 0.1-2.0 mg L−1 copper(II) with a correlation coefficient 0.9985 and a slope of 0.2893 absorbance unit/mg L−1. The relative standard deviation was 2.0% for a series of 10 measurements of 0.5 mg L−1 copper(II) solution. The detection limit (3 S/N) and the limit of quantification (LOQ) were 0.05 and 0.17 mg L−1 respectively. This method has been successfully applied to determination of copper(II) in wastewater with a sample throughput of 120 h−1. The method is superior to the batchwise method in that it provides fully automation, rapidity, less reagents and sample consumption with little waste generation. 相似文献
16.
Xijun Chang Zhenhua Li Yuemei Cui Xiangbing Zhu Zhipeng Zang 《Microchemical Journal》2008,90(1):71-76
A method is described for the selective extraction of chromium(III) from aqueous solutions and natural water samples, based on the use of two newly synthesized solid-phase extractors via silica gel-immobilized-vanillin derivatives (I,II). Experimental conditions for effective adsorption of trace levels of Cr(III) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH values for the separation of Cr(III) simultaneously on the newly sorbents were both 4.0 and complete elution of Cr(III) from the sorbents surface was carried out using 2.0 mL of 0.5 mol L− 1 HCl. The sorption capacity of phase I towards Cr(III) was found to be 0.700 mmol g− 1 where the sorption capacity of phase II was 0.538 mmol g− 1. The detection limits (3σ) of the method defined by IUPAC were found to be 0.87 and 0.64 ng mL− 1 with enrichment factors of 100 and 75 for phases I and II, respectively. The method has been applied for the determination of Cr(III) in biological materials and water samples with satisfactory results. 相似文献
17.
A flow system exploiting the multicommutation approach is proposed for spectrophotometric determination of tannin in beverages. The procedure is based on the reduction of Cu(II) in the presence of 4,4′-dicarboxy-2,2′-biquinoline, yielding a complex with maximum absorption at 558 nm. Calibration graph was linear (r = 0.999) for tannic acid concentrations up to 5.00 μmol L− 1. The detection limit and coefficient of variation were estimated as 10 nmol L− 1 (99.7% confidence level) and 1% (1.78 μmol L− 1 tannic acid, n = 10), respectively. The sampling rate was 50 determinations per hour. The proposed procedure is more sensitive and selective than the official Folin-Denis method, also minimizing drastically waste generation. Recoveries within 91.8 and 115% were estimated for total tannin determination in tea and wine samples. 相似文献
18.
A new cadmium(II)-imprinted polymer based on cadmium(II) 2,2′-{ethane-1,2-diylbis[nitrilo(E)methylylidene]} diphenolate-4-vinylpyridine complex was obtained via suspension polymerization. The beads were used as a minicolumn packing for flow-injection-flame atomic absorption spectrometry (FI-FAAS) determination of cadmium(II) in water samples. Sorption effectiveness was optimal within pH range of 6.6-7.7. Nitric acid, 0.5% (v/v) was used as eluent. Fast cadmium(II) sorption by the proposed material enabled to apply sample flow rates up to 10 mL min−1 without loss in sorption effectiveness. Enrichment factor (EF), concentration efficiency (CE) and limit of detection (LOD, 3σ) found for 120-s sorption time were 117, 39.1 min−1 and 0.11 μg L−1, respectively. Sorbent stability was proved for at least 100 preconcentration cycles (RSD = 2.9%). When compared to non-imprinted polymer the new Cd(II)-imprinted polymer exhibited improved selectivity towards cadmium(II) against other heavy metal ions, especially Cu(II) and Pb(II), as well as light metal ions. Accuracy of the method was tested for ground water and waste water certified reference materials and fortified water. The method was applied to Cd(II) determination in natural water samples. 相似文献
19.
Y. Kayser D. Banaś W. Cao J.-Cl. Dousse J. Hoszowska P. Jagodziński M. Kavčič A. Kubala-Kukuś S. Nowak M. Pajek J. Szlachetko 《Spectrochimica Acta Part B: Atomic Spectroscopy》2010
The synchrotron radiation based high-resolution grazing emission X-ray fluorescence (GEXRF) technique was used to extract the distribution of Al ions implanted with a dose of 1016 atoms/cm2 in Si wafers with energies ranging between 1 and 100 keV. The depth distributions of the implanted ions were deduced from the measured angular profiles of the Al-Kα X-ray fluorescence line with nanometer-scale precision. The experimental results were compared to theoretical predictions of the depth distributions resulting from ion implantation. A good agreement between experiment and theory was found which proved that the presented high-resolution grazing emission X-ray fluorescence technique is well suited to perform depth profiling measurements of impurities located within the extinction depth, provided the overall shape of the distribution can be assumed a priori. 相似文献
20.
Mark P. Jensen Baikuntha P. Aryal Drew Gorman-Lewis Tatjana Paunesku Barry Lai Stefan Vogt Gayle E. Woloschak 《Analytica chimica acta》2012
Synchrotron-based X-ray fluorescence microscopy (XFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurements such as μ-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L3 or L2-edge as well as Th and lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope 242Pu. Elemental maps demonstrate that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions with an incident X-ray energy of 18 keV for an average 202 μm2 cell is 1.4 fg Pu or 2.9 × 10−20 moles Pu μm−2, which is similar to the detection limit of K-edge XFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its Lα X-ray emission. 相似文献