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Studies the luminescence spectroscopy of atomic cadmium isolated in solid rare gases. Steady-state and time-resolved analysis of ultraviolet emission bands; Intensity of the triplet state emission; Comparisons between the behavior observed in previous matrix luminescence studies.

Isotope dilution ICP-MS is proposed to measure the mass fraction of Cd extracted by diluted HCl in marine sediments, using a fast and simple extraction procedure based on ultrasonic probe agitation. The 111 Cd isotope was added before the extraction to achieve isotope equilibration with native Cd solubilized from the sample. The parameters affecting trueness and precision of isotope ratio measurements were evaluated carefully and subsequently corrected in order to minimize errors; they were: detector dead time, spectral interferences, mass discrimination factor and optimum sample/spike ratio. The mass fraction of Cd extracted was compared with the sum of the certified contents of the three steps of the sequential extraction procedure of the Standards, Measurements and Testing Programme (SM&T) analysing the BCR 701 sediment to validate the method. The certified and measured values agreed, giving a measured / certified mass fraction ratio of 1.05. Further, the extraction procedure itself was studied by adding the enriched isotope after the extraction step, which allowed verifying that analyte losses occurred during this process. Two additional reference sediments with certified total cadmium contents were also analysed. The method provided very good precision (0.9%, RSD) and a low detection limit, 1.8 ng g −1 . The procedural uncertainty budget was estimated following the EURACHEM Guide by means of the ‘GUM Workbench’ software, obtaining a relative expanded uncertainty of 1.5%. The procedure was applied to determine the bioaccessible mass fraction of Cd in sediments from two environmentally and economically important areas of Galicia (rias of Arousa and Vigo, NW of Spain). [ABSTRACT FROM AUTHOR]

A method for the trace determination of cadmium ions in water, human urine and human blood serum samples using ultrasonic‐assisted dispersive micro‐solid‐phase extraction (UA‐D‐μSPE) was developed. Silica‐coated magnetic nanoparticles were coated with polythiophene, and the resulting sorbent was characterized using thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X‐ray diffraction. Following UA‐D‐μSPE, cadmium ions were quantified using graphite furnace atomic absorption spectrometry. A Box–Behnken design was used for optimization of important sorption and desorption parameters in UA‐D‐μSPE: in the sorption step, pH of solution, sorption amount and sonication time for sorption; in the desorption step, concentration of eluent, volume of eluent and sonication time. The optimum conditions for the method were: pH of solution, 7.5; sonication time for sorption, 3 min; sorption amount, 35 mg; type and concentration of eluent, HCl and 1.1 mol l−1; volume of eluent, 360 μl; sonication time for desorption, 110 s. Under the optimized conditions the limit of detection and relative standard deviation for the detection of cadmium ions by UA‐D‐μSPE were found to be 0.8 ng l−1 and <6%, respectively. [ABSTRACT FROM AUTHOR]

Chemical state of cadmium in a hepatopancreas of a scallop (Patinopecten yessoensis) was studied by means of synchrotron radiation‐based X‐ray analytical techniques. X‐ray absorption fine structure (XAFS) and X‐ray fluorescence (XRF) imaging were used to identify the chemical state and the distribution of cadmium in the hepatopancreas, respectively. The results of invivo Cd K‐edge XAFS suggested that the neighboring atoms of the cadmium in the hepatopancreas are of sulfur. Therefore, we propose that cadmium was accumulated by a metalloprotein with sulfur. Micro XRF imaging of thin sections of the hepatopancreas showed that cadmium is distributed on the surface of intestinal epithelia and concentrated in the internal tissue of the hepatopancreas. These results indicated that scallops accumulate cadmium inside the hepatopancreas through the intestinal epithelium. [ABSTRACT FROM AUTHOR]

Novel hybrid material was prepared by adding slurries of poly(N-methylaniline) and cerium tungstate [Ce2(WO4)3] into a conical flask contained dispersed carbon nanotubes. It was characterized by scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Electrical conductivity of poly(N-methylaniline)-Ce2(WO4)3@carbon nanotube samples was determined using four-probe method. The thin layer of poly(N-methylaniline)-Ce2(WO4)3@carbon nanotube was fabricated onto glassy carbon electrode for a selective Cd2+ion sensor. The calibration plot is linear (r2 = 0.9917) over the large Cd2+concentration ranges (1.0 nM–1.0 mM). The sensitivity, detection limit is ∼5.138 µA µM−1 cm−2and ∼0.11 nM (signal-to-noise ratio, at a SNR of 3), respectively. [ABSTRACT FROM PUBLISHER]

A chalcone-based naked-eye colorimetric chemical sensor, (E)-4-hydroxy-3-(3-(4-methoxyphenyl)acryloyl)-2H-chromen-2-one 1a, was developed for selective and sensitive recognition of Cd2+ in mixed aqueous–organic media. The chemosensor demonstrates a distinct color change as well as a remarkable variation in the absorption and fluorescence enhancement observed in its emission spectra upon interaction with Cd2+. The dual colorimetric and fluorometric responses of the chemosensor 1a towards Cd2+ are attributed to the formation of a 1 : 1, 1a–Cd2+ complex, which eventually affect its optical properties. The association constants for Cd2+ towards receptor 1a obtained from the Benesi–Hildebrand plot and non-linear least square fitting were found to be 9.56 × 105 M−1 and 1.34 (±0.87) × 106 M−1, respectively, with a detection limit of 5.84 × 10−8 M. The fluorescence enhancement of chemosensor 1a upon interaction with Cd2+ was attributed to chelation-enhanced fluorescence (CHEF) occurring at pH 7.0. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain indigenously the mesoporous silica (AMS) precursor to 3-aminopropyltriethoxysilane (APTES) and utilizing chitosan a templating natural biopolymer. The textural characteristics of AMS were obtained by the SEM (Scanning Electron Microscopy) and BET (Brunauer–Emmett–Teller) surface area measurements. AMS solid possessed specific surface area of 511.77 m 2 /g and having pore size and pore volume of 3.38 nm and 0.036 cm 3 /g, respectively. Further, the AMS was characterized by the XRD (X-ray Diffraction) and FT-IR (Fourier Transform- Infra Red) analyses. The mesoporous silica was employed for efficient removal of cadmium(II) and lead(II) from aqueous solutions. The influence of solution pH, initial cadmium(II)/or lead(II) concentrations, contact time, and background electrolyte concentrations were studied to deduce the mechanism involved at solid/solution interface. The equilibrium state adsorption data were utilized for the Langmuir and Freundlich adsorption isotherms and the Langmuir adsorption isotherm showed a good agreement with the experimental data. Uptake was found to be fairly fast and the kinetic modelling suggested that the adsorption of cadmium(II)/or lead(II) by AMS was occurred through fractal-like pseudo-second order kinetics. An increase in background electrolyte concentrations from 0.0001 to 0.01 mol/L NaNO 3 did not affect the removal of lead(II), whereas the cadmium(II) removal was slightly suppressed. The XPS (X-ray Photoelectron Spectroscopy) analysis indicated that removal of cadmium(II) or lead(II) occurred through the formation of a chemical bond with the oxygen atoms present with AMS solid. Furthermore, fixed-bed column adsorption was conducted and the loading capacity of cadmium(II) and lead(II) was found to be 11.54 and 8.59 mg/g, respectively. [ABSTRACT FROM AUTHOR]

A systematic approach is proposed to evaluate microwave-assisted digestion in a single reaction chamber for the simultaneous determination of elements in the mineral fertilizer and raw material by inductively coupled plasma optical emission spectrometry. A reference material was digested using 12 acid mixtures containing nitric, hydrochloric, orthophosphoric, hydrofluoric or boric acid. Principal components analysis was applied for data treatment. Three digestion procedures based on diluted acids exhibited the most accurate results, with relative errors for reference values ranging from −15% to + 9%. Limits of quantification were in the range of 0.2 mg cadmium kg−1up to 1000 mg aluminum kg−1. [ABSTRACT FROM AUTHOR]

In this study, a novel nanostructured cadmium(II) ion imprinted polymer (Cd–IIP) was prepared through sol–gel process. The prepared material was characterized by Fourier transform infrared spectroscopy (FT–IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and energy dispersive X-ray (EDX) analysis. The resulting Cd–IIP material was employed for modification of simple and low-cost carbon paste electrode (CPE). The differential pulse anodic stripping voltammetric (DPASV) technique was applied for determination of toxic cadmium(II) ions after closed circuit sorption on the MCPE. The best electrochemical response for Cd(II) ions was obtained with a paste composition of 10% (w/w) of cadmium(II)–IIP, 65% (w/w) of graphite powder and 25% (w/w) of paraffin oil using a solution of 0.1 mol L −1 phosphate buffer solution (PBS, pH = 5) with accumulation potential of −1.1 V and accumulation time of 300 s. The proposed electrochemical sensor showed excellent selectivity and stability for Cd(II) analysis. The electrode displayed a linear behavior in the concentration range of 0.5–40 µg L −1 Cd(II) with a low detection limit of 0.15 μg L −1 (at S/N = 3). The designed sensor was further utilized for the determination of cadmium in different water samples with satisfactory results. [ABSTRACT FROM AUTHOR]

I-III-VI semiconductor quantum dots (QDs) without Cd element have attracted considerable attention in the optoelectronics device areas. Herein, we demonstrated that AgInS 2 QDs with tunable photoluminescence were used for light emitting diodes (LEDs). With the increase of reaction temperature, the photoluminescence (PL) peak was monotonically red shifted from 600 to 750 nm. The temperature-dependent lifetime of the photoluminescence emission could reach to 900 ns. The successful synthesis of the AgInS 2 nanocrystals with long PL lifetime provided a potential application in LEDs. The fabricated QDs LEDs exhibited a relative low turn-on voltage of 2.9 V and a maximum luminance intensity of 122 cd/m 2 . [ABSTRACT FROM AUTHOR]

Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain 113Cd spectra from CdTe-COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium-rich surface. [ABSTRACT FROM AUTHOR]

The adsorption behavior of some lowcost adsorbents such as bentonite, meal thistle and carbonized walnut husk with respect to Cd2+ ions in aqueous solutions has been studied. The several process parameters (contact time, initial metal concentration, sorption capacity, extraction degree, rate constants, sorption rates and sorption energy) were found. For the Cd2+ ions adsorption the equilibrium time onto bentonite, meal thistle and carbonized walnut husk were found to be 2 h, 25 and 10 min, respectively. Adsorption parameters were determined using both Langmuir and Freundlich isotherms. Sorption isotherms of cadmium ions onto MBT (modified bentonite) and MTM (modified thistle meal) were the best of all described by the equation of Freundlich sorption (correlation coefficients are closest to unit). In contrast the sorption of Cd2+ ions onto MCWH (modified carbonized walnut husk) was described by the Langmuir isothermic model where the adsorption occurs on homogeneous surface by monolayer sorption without interaction between sorbed ions. The obtained results demonstrate that bentonite, meal thistle and carbonized walnut husk can remove Cd2+ ions from aqueous solutions. It means that cheap and available raw materials can be efficient adsorbents and capable to remove cationic heavy metal species from waste water. The ion-exchange mechanism of adsorption of cadmium ions by the MBT, MTM, MCWH was proposed. [ABSTRACT FROM AUTHOR]

Herein, we report the preparation of nanorods-like Cd(OH)2-rGO nanocomposites via using a simple co-precipitation method. The as-prepared Cd(OH)2-rGO materials were characterized by a variety of analytical and spectroscopy techniques such as scanning electron microscope (SEM), elemental analysis (EDX), X-ray diffraction (XRD), and Raman spectroscopy. Interestingly, Cd(OH)2-rGO modified glassy carbon electrode (GCE) employed for the electrochemical detection of acetaminophen (AP) sensor for first time by using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The AP sensor exhibited an ultra-high sensitivity of 24.452 µA µM−1 cm−2 and a low detection limit 0.08 µM with wider linear ranges from 0.1 to 102 µM. Notably, the obtained analytical parameters of the AP sensor using nanorods-like Cd(OH)2-rGO modified GCE is superior than several rGO based nanocomposites suggesting more suitable for several practical pharmaceutical applications. [ABSTRACT FROM AUTHOR]

The synthesis, structures and properties of eight coordination polymers {[Zn( L 1 )(oba)]·2H 2 O} n [ L 1 = N,N′ -di(4-pyridyl)adipoamide; H 2 oba = 4,4 ′ -oxybis(benzoic acid)], 1 , {[Zn( L 1 )(sda)]·2H 2 O} n (H 2 sda = 4,4 ′ -sulfonyldibenzoic acid), 2 , [Cd(4-apy) 2 (oba)] n (4-apy = 4-aminopyridine), 3 , [Cd(oba)(H 2 O) 2 ] n , 4 , {[M( L 2 )(1,4-pda)(H 2 O) 2 ]·2H 2 O} n , (M = Ni, 5 ; Co, 6 ; L 2 = N,N′ -di(3-pyridyl)suberoamide; 1,4-H 2 pda = 1,4-phenylenediacetic acid), {[Cd( L 2 )(1,4-pda)]·2H 2 O} n , 7 , and [Cu( L 2 )(1,4-bdc)(H 2 O) 2 ] n (1,4-H 2 bdc = 1,4-benzenedicarboxylic acid), 8 , are reported. Complex 1 is a 1D → 2D polycatenane derived from the helical channels, and the 2D layers are further mutually interdigitated. The 1D looped chains of 2 are interlinked through O H⋯O hydrogen bonds and the 1D zigzag chains of 3 are interlinked through N H⋯O hydrogen bonds, resulting in 2D supramolecular structures, whereas the cadmium(II) cations of 4 are linked by the oba 2− ligands and water molecules to form a 3D network with the dia topology. The structures of complexes 5 , 6 and 8 can be simplified as 4-connected 2D nets with the sql topology and complex 7 exhibits a double layer, showing a 3,5-connected net with the (4 2 .6 7 .8)(4 2 .6)-3,5L2 topology. The structural types of the L 1 -based divalent coordination polymers are subject to the change of the angular dicarboxylate ligands, whereas the structural difference in 5 – 7 based on 1,4-pda 2− and L 2 ligand can be ascribed to the size of the central metal atom. Their thermal, luminescent and catalytic properties are also discussed. [ABSTRACT FROM AUTHOR]

We report first-ever Compton profiles of ZnMoO4 and CdMoO4 measured using photons of 661.65 keV emitted by 20 Ci 137Cs γ-ray source. To interpret the experimental momentum densities, we have also computed the electronic properties which include band structure, density of states (DOS), electron momentum density, Mulliken's population (MP), and anisotropy in Compton profiles using linear combination of atomic orbitals (LCAO) scheme with density functional theory. In addition, more accurate energy bands and DOS have been computed using full-potential linearized augmented plane wave method with modified Becke-Johnson potential (FP-LAPW-mBJ). The band gap values of ZnMoO4 and CdMoO4 calculated using FP-LAPW-mBJ approximation were found to be close to available experimental data. It is seen that momentum densities computed using LCAO scheme with PBEsol approximation gives a better agreement with the present measurements than other DFT approximations considered in the present work. On the basis of equal-valence-electron-density profiles, it is seen that ZnMoO4 has more covalent nature than CdMoO4 which is in tune with the present integrated DOS and Mulliken's population data. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks, namely, [Cd(L)(H2O)] n ( 1) and {[Cd0.5(L)(4,4′-bipy)0.5][Cd0.5(H2O)(4,4′-bipy)0.5]·H2O} n ( 2), where H2L = N-pyrazinesulfonyl-glycine and 4,4′-bipy = 4,4′-bipyridine, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric, and photoluminescent analysis. X-ray diffraction crystallographic analyses indicate that 1 displays a distorted octahedral metal coordination in a 3-connected (4, 82) topology, while the molecular structure of 2 has a 4-connected (4, 4) topology with two perfectly octahedrally coordinated Cd centers. The L2- ligand serves as a N,N,O-tridentate, μ2-pyrazine-bridging, and μ2-carboxylate-bridging ligand in 1, and as a N,O-bidentate and μ2-carboxylate-bridging ligand in 2. In the crystal, a 3D supramolecular architecture is formed by O-H···O hydrogen bond interactions in 1, but through O-H···O as well as π··· π stacking in 2. The two compounds show intense fluorescence in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

A versatile new fluorogenic Schiff base probe (L) has been synthesized by the reaction of quinoline-2-carbohydrazide (which acts as the chelating site) and 4-dimethylamino cinnamaldehyde (which acts as the signaling unit). L can sense three of the most biologically and environmentally important metal ions, Zn2+, Cd2+ and Pb2+, among various tested metal ions through selective TURN-ON fluorescence responses in physiological pH. Interestingly, L can not only sense Zn2+, Cd2+ and Pb2+ fluorometrically in physiological conditions but can also distinguish one from another by exhibiting individual intrinsic left-right-center TURN-ON emission signal swings. These selective fluorescence responses were explained by a chelation-enhanced fluorescence (CHEF) mechanism. Theoretical calculations were carried out to ascertain the preferred L–metal ion binding mode. [ABSTRACT FROM AUTHOR]

RATIONALE: The azide method for measuring the stable isotope ratios of nitrate (NO3-) is easy to set up. However, the method requires spongy cadmium (Cd) or activated Cd powder which are not easy to prepare, and a toxic azide buffer is used. We aimed to use Cd powder directly to simplify preparation and to substantially reduce the azide dose. METHODS: The reaction conditions were optimized in order to maximize the NO3- reduction yield. The original azide buffer was diluted by 10- to 10000-fold with or without addition of sodium acetate to reduce O-exchange between nitrite (NO2-) and H2O. The isotope ratios of the produced nitrous oxide (N2O), used to examine the overall reaction performance, were measured using a purge and cryogenic trap system coupled to an isotope ratio mass spectrometer. RESULTS: It was found that Cd powder could be directly used to reduce NO3- to NO2-. A 100-fold diluted azide buffer could be used to reduce NO2- to N2O when only the δ15N value was measured, and the diluted azide buffer with sodium acetate when both δ15N and δ18O values were measured. Using the modified method, the standard deviations of the δ15N and δ18O measurements of international NO3- standards were 0.1 to 1.0 and often better than 0.3 (3 replicates). CONCLUSIONS: Compared with the original azide method, the techniques described here can reduce preparation time by using Cd powder without activation in the first reaction step and substantially (by >60-fold) reduce the dose of extremely toxic reagents containing azide by incorporating sodium acetate in the second reaction step. Our modified method is suitable for samples with small volume (5 mL), being different from previous methods in which 50 or 70 mL samples were used. [ABSTRACT FROM AUTHOR]

A new digestion method using UV-assisted Fe0 Fenton reaction was developed for the determination of trace Cd in rice by hydride generation atomic fluorescence spectrometry. The proposed method integrated the advantages of simplicity, small dose of reagents, low cost and moderate reaction conditions, and was successfully utilized to analyze a Certified Reference Material (CRM) and real rice samples. A 1 mL mixture of the sample and reagents (0.0500 g rice powder, 0.2% (m/v) Fe0, 0.75% (v/v) HNO3 and 18% (v/v) H2O2) was irradiated by UV-light for 50 min and then a clear solution was obtained by separating excess Fe0 with a magnet prior to spectral analysis. The limit of detection (LOD) for Cd was found to be 0.02 mg kg−1 and the relative standard deviation was better than 5.0% at a concentration level of 0.40 mg kg−1. The recovery obtained by analyzing the CRM was 103% and spiked recoveries with 0.40 mg kg−1 Cd in rice samples were 93% and 101%. The t-test proved that there is no significant difference between the certified value and the determined value of the CRM, and between the proposed method and microwave-assisted digestion coupled with inductively coupled plasma mass spectrometry (MWD-ICP-MS) at 95% confidence level. [ABSTRACT FROM AUTHOR]

The distribution of the electromagnetic dipole strength below the neutron separation energy and its influence on the photon distribution after neutron capture were investigated in two experiments for the compound nucleus 114Cd. By measuring the photoabsorption cross section at the bremsstrahlung facility γ ELBE at Helmholtz-Zentrum Dresden-Rossendorf it was possible to deduce the distribution of dipole strength below the neutron separation energy. The de-excitation spectrum after cold-neutron capture in 113Cd was measured at the Budapest Neutron Center. In a combined analysis, the experimentally deduced spectra after photon scattering on 114Cd and the neutron capture in 113Cd were analyzed in terms of electric and magnetic strength functions and nuclear level density with the help of the statistical code γ DEX. [ABSTRACT FROM AUTHOR]

The anisotropy parameter values β of the L shell fluorescent X-rays (Lι (L3-M1), Lβ6 (L3-N1), Lα1,2 (L3-M5,4) and Lβ2,15 (L3-N5,4) of Bi, Pb, Ta, Lu, and Yb excited by 22.6 keV photons were measured. These values were used to determine the kinematic coefficient ratios α(Lι/Lα1,2), α(Lι/Lβ6), and α(Lα1,2/Lβ2,15). The Lι and Lβ6 X-rays were found to be anisotropically emitted whereas Lα1,2 and Lβ2,15 X-rays showed less anisotropic spatial distributions. Also, the polarization degrees of Lι and Lα X-rays were measured for the present elements and observed that the Lι lines were found to be strongly polarized whereas the Lα lines showed less polarization. [ABSTRACT FROM AUTHOR]

The present publication investigates the performance of nanocrystalline Ni (15 wt.%)-doped α-Fe2O3 as an effective nanomaterial for the removal of Cd(II) ions from aqueous solutions. The nanocrystalline Ni-doped α-Fe2O3 powders were prepared by mechanical alloying, and characterized by X-ray diffraction and a vibrating sample magnetometer. Batch-mode experiments were realized to determine the adsorption equilibrium, kinetics, and thermodynamic parameters of toxic heavy metal ions by Ni (15 wt.%)-doped α-Fe2O3. The adsorption isotherms data were found to be in good agreement with the Langmuir model. The adsorption capacity of Cd(II) ion reached a maximum value of about 90.91 mg g-1 at 328 K and pH 7. The adsorption process kinetics was found to comply with pseudo-second-order rate law. Thermodynamic parameters related to the adsorption reaction, free energy change, enthalpy change and entropy change, were evaluated. The found values of free energy and enthalpy revealed a spontaneous endothermic adsorption-process. Moreover, the positive entropy suggests an increase of randomness during the process of heavy metal removal at the adsorbent--solution interface. [ABSTRACT FROM AUTHOR]

Photocatalytic H 2 production from water is one of the most attractive issues for the conversion of solar energy into chemical energy. In this study, the Ni x B/CdS photocatalyst was firstly used for photocatalytic H 2 -evolution reaction and showed efficient visible-light photocatalytic activity and good stability for H 2 -evolution from aqueous solution. The optimal Ni x B loading content was determined to be 0.8 wt.%, and the corresponding H 2 -production rate reached up to 4.8 mmol·h − 1 ·g − 1 after a 10 h visible light irradiation. It is proposed that the loading of Ni x B on the surface of CdS could effectively increase the separation of photo-generated electrons and holes and greatly enhance the photocatalytic activity. [ABSTRACT FROM AUTHOR]

A novel Cd-MOF (metal organic framework) [Cd3(NTB)2(DMA)3]·2DMA (H3NTB = 4,4′,4′′-nitrilotrisbenzoic acid; DMA = N,N-dimethylacetamide) (1) was obtained under solvothermal conditions. The resulting MOF exhibits a novel (2D→3D) interdigitated architecture that is obtained from a bilayered motif with hexagonal grids. Luminescence properties of the activated phase of 1a well dispersed in different solvents have also been investigated systematically, which demonstrate distinct solvent-dependent luminescence spectra with emission intensities significantly quenched toward nitrobenzene (NB) and 2,4,6-trinitrophenol (TNP). The results reveal that 1 can be applied as a fluorescent sensor for the detection of TNP with high sensitivity, selectivity, and recyclability. [ABSTRACT FROM AUTHOR]

In vitro selection was performed to search for RNA-cleaving DNAzymes catalytically active with Cd2+ ions from the oligonucleotide combinatorial library with a 23-nucleotide random region. All the selected, catalytically active variants turned out to belong to the 8–17 type DNAzyme. Three DNAzymes were prepared in shortened, cis-acting versions which were subjected to a detailed study of the kinetic properties and metal ion preferences. Although the selection protocol was designed for Cd2+-dependent DNAzymes, the variants showed broader metal ion specificity. They preferred Cd2+ but were also active with Mn2+ and Zn2+, suggesting that binding of the catalytic ion does not require an extremely specific coordination pattern. The unexpected decrease of the catalytic activity of the variants along with the temperature increase suggested that some changes occurred in their structures or the rate-limiting step of the reaction was changed. Two elements of the catalytic core of DNAzyme 1/VIIWS, the nucleotide at position 12 and the three-base-pair hairpin motif, were mutated. The presence of a purine residue at position 12 was crucial for the catalytic activity but the changes at that position had a relatively small influence on the metal ion preferences of this variant. The middle base pair of the three-base-pair hairpin was changed from A–T to C–G interaction. The catalytic activity of the mutated variant was increased with Zn2+, decreased with Mn2+, and was not changed in the presence of Cd2+ ions. Clearly, this base pair was important for defining the metal ion preferences of the DNAzyme 1/VIIWS. [ABSTRACT FROM AUTHOR]

Cd3As2 is a candidate three-dimensional Dirac semimetal which has exceedingly high mobility and nonsaturating linear magnetoresistance that may be relevant for future practical applications. We report magnetotransport and tunnel diode oscillation measurements on Cd3As2, in magnetic fields up to 65 T and temperatures between 1.5 and 300 K. We find that the nonsaturating linear magnetoresistance persists up to 65 T and it is likely caused by disorder effects, as it scales with the high mobility rather than directly linked tofermi surface changes even when approaching the quantum limit. From the observed quantum oscillations, we determine the bulk three-dimensional Fermi surface having signatures of Dirac behavior with a nontrivial Berry phase shift, very light effective quasiparticle masses, and clear deviations from the band-structure predictions. In very high fields we also detect signatures of large Zeeman spin splitting (g ∼ 16). [ABSTRACT FROM AUTHOR]

The present paper proposes the use of a multi-syringe flow injection analysis (MSFIA) system for the determination of Cd in natural water by cold vapour atomic absorption spectrometry (CV-AAS). The chemical and physical conditions for vapour generation were investigated and optimized using multivariate optimization methodology. Some complexing reagents were tested as additives to increase the analytical signal. Thiourea showed a positive effect, whereas L-cysteine reduced the signal of Cd. The method allows the direct determination of Cd, i.e. without sample pre-concentration, with limits of detection and quantification of 5.8 and 19.3 ng L-1, respectively, and employing external calibration technique. The precision expressed as a relative standard deviation varied between 1.4% and 2.9% for two levels of cadmium (0.25 and 2.5 µg L-1). Using 2 mL of sample volume, an injection throughput of 87 hr-1 was achieved. The accuracy was confirmed by the analysis of a certified reference sample of seawater (CASS-4) furnished by National Research Council of Canada and addition/recovery tests, obtaining recoveries between 94% and 101%. The method was satisfactorily applied for the determination of Cd in seawater and ground water samples from Mallorca, Spain. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWCNTs) were used as sorbent for solid phase extraction (SPE) of cadmium ions from water samples. After extraction, volatile cadmium species were generated in the presence of propionic acid under ultraviolet radiation (photochemical generation, UV CVG) and determined by high-resolution continuum source atomic absorption spectrometry (HR-CS AAS) with quartz tube atomization (QTA). The experimental parameters including pH of the solutions, amount of MWCNTs, flow rate of sample, eluent concentration, maximum sample volume and coexisting ions, as well as main parameters of UV CVG HR-CS QTA AAS were investigated. The effective preconcentration of trace cadmium was achieved in pH 7 and the retained cadmium was efficiently eluted with 0.5 mol L-1 HNO3. The limit of detection was 25 µg L-1 and the achieved preconcentration factor was 8.8. The relative standard deviation (RSDs) was 15%. The accuracy of this method was validated by the analyses of NIST SRM 1643e (trace elements in water) and ERM-CA011b (hard drinking water) certified reference materials. The element contents measured in these reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The presented method was successfully applied for the determination of cadmium in four different water samples (seawater, lake water, mine water and tap water). [ABSTRACT FROM AUTHOR]

In this work, the growth of isolated Cd1-xMgxO nanoparticles on r-sapphire substrates is extended to the entire range of Mg content (0 ≤ x ≤ 1) using the spray pyrolysis method. The sizes of the Cd1-xMgxO nanoparticles were in the ranges 4-6 nm and 15-30 nm (with a nanoparticle density of 1010 cm-2). The composition of the nanoparticles was determined using transmission electron microscopy energy dispersive X-ray analysis (TEM-EDAX), while the compound formation was confirmed using X-ray photoelectron spectroscopy. A systematic decrease in the a lattice parameter of Cd1-xMgxO on increasing the Mg content substantiated the successful incorporation of Mg2+ ions into the cubic CdO lattice. Single-phase cubic Cd1-xMgxO nanoparticles were obtained in the range of nominal Mg content 0% to 30% (0 ≤ x ≤ 0.26), whereas a Mg content of about 40% (nominal) forced a phase separation where Cd1-xMgxO and Mg1-xCdxO co-exist (the Mg nominal content was 40% to 90%), providing experimental evidence of the phase separation that exists in the MgO-CdO system. This phase separation was detected using selected area electron diffraction and X-ray diffraction measurements. Cross-sectional transmission electron microscopy analysis shows the growth of a single layer of isolated and crystalline Cd1-xMgxO nanoparticles over the r-sapphire substrate. [ABSTRACT FROM AUTHOR]

Transition metal manganese ion (Mn) doped zinc selenide quantum dots (Mn:ZnSe D-Dots) have been considered as a new material for fluorescent probes in biological labeling. However, this application is limited by the low membrane permeability of D-Dots. In this work, Mn:ZnSe D-Dots were capped with the polycation Sofast to label living cells. For the first time, the efficiency of cellular uptake in living cells is significantly enhanced. Various molar ratios of Sofast to D-Dots were explored and compared to obtain the optimal reaction conditions between Sofast and D-Dots for preparing Sofast/D-Dots nano-compound. A comparison on the fluorescence labeling ability of living cells were made between Sofast/D-Dots and pure D-Dots. Results from laser scanning confocal microscope show that Sofast/D-Dots complexes enter the cells more efficiently than pure D-Dots, even with a lower concentration and shorter incubation time. The cytotoxicities of D-Dots and Sofast/D-Dots were also studied. It was found that Sofast/D-Dots have a much lower cytotoxicity than cadmium-containing quantum dots (i.e. CdTe and CdTe/ZnS). Our results suggest that the non-heavy-metal-containing Sofast/D-Dots complexes have a great potential in the application of biological labeling, especially of long-time bioimaging in living cells. [ABSTRACT FROM AUTHOR]

Three new ferrocene based Schiff bases 4-{[( E)-ferrocenylmethylidene] amino}benzenethiol ( 1b), 3-{[( E)-ferrocenylmethylidene]amino} benzenethiol ( 1c), 2-{[( E)-ferrocenylmethylidene]amino} benzenethiol ( 1d) have been synthesized to study their sensor property to various metal ions. It has been observed that 1b is highly fluorescent and its fluorescence changes in presence of metal ions. It was further observed that compound 1b is highly selective towards Cd ion in solution. [ABSTRACT FROM AUTHOR]

Two pairs of novel enantiomerically chiral clusters R/S-[NaMnIIMnIII 3L3(μ3-O)] (R/S-1) and R/S-[Na2MnII 2- MnIII 6L6(μ3-O)2] (R/S-2) have been obtained via the self-assembly of R/S-H2L Schiff base ligands and different auxiliary ligands (N3 -, dca-) with divalent manganese salt in an air-exposed methanol-ethanol solution. The structures of R/S-1 and R/S-2 were characterized by single-crystal X-ray diffraction analysis and powder X-ray diffraction. When the dicyanamide anion serves as an auxiliary ligand in the assembling reaction system, a pair of enantiomeric clusters R/S-[NaMnIIMnIII 3L3(μ3-O)] (R-1 and S-1) with a trigonal bipyramid configuration were obtained, while another pair of enantiomeric clusters R/S-[Na2MnII 2- MnIII 6L6(μ3-O)2] (R-2 and S-2) were formed in the case of the azide. Interestingly, the skeleton configuration of R/S-2 can be described as a 3-fold EO-azide bridging double trigonal bipyramid of [NaMnIIMnIII 3L3(μ3-O)]2 via MnII vertices. Circular dichroism (CD) spectra demonstrated the enantiomeric nature of the two pairs of clusters. Detailed direct current (DC) magnetic susceptibility studies in the temperature range 2-300 K suggested that R-1 and R-2 showed predominantly antiferromagnetic interactions between the manganese centers. [ABSTRACT FROM AUTHOR]

Due to its favorable spectroscopic properties, Cd2+ is frequently used as a probe of Ca2+ sites in proteins. We investigate the ability of Cd2+ to act as a structural and functional surrogate of Ca2+ in protein-membrane interactions. C2 domain from protein kinase Cα (C2α) was chosen as a paradigm for the Ca2+-dependent phosphatidylserine-binding peripheral membrane domains. We identified the Cd2+-binding sites of C2α using NMR spectroscopy, determined the 1.6 Å crystal structure of Cd2+-bound C2α, and characterized metal-ion-dependent interactions between C2α and phospholipid membranes using fluorescence spectroscopy and ultracentrifugation experiments. We show that Cd2+ forms a tight complex with the membrane-binding loops of C2α but is unable to support its membrane-binding function. This is in sharp contrast with Pb2+, which is almost as effective as Ca2+ in driving the C2α-membrane association process. Our results provide the first direct evidence for the specific role of divalent metal ions in mediating protein-membrane interactions, have important implications for metal substitution studies in proteins, and illustrate the potential diversity of functional responses caused by toxic metal ions. [ABSTRACT FROM AUTHOR]

In the present work, multiwalled carbon nanotube (MWCNT) chemically modified with (3-mercaptopropyl) silanetriolate is efficiently used for the solid-phase extraction of Cu2+, Ag+, Cd2+, Pb2+, Zn2+ and Mn2+ ions prior to their flame atomic absorption spectrometric determination. The influences of the various analytical parameters, including pH, amounts of solid phase, sample volume and eluent conditions and so on, on the recoveries of target analytes were investigated and optimized by one at a time optimization method. The influences of alkaline, alkaline earth and some transition metals on the adsorption and elution of the analytes were also examined. The detection limits for all understudied metal ions were between 1.4 and 2.8 ng mL−1 (3Sb, n = 10). The evaluation of the thermodynamic parameters such as enthalpy (positive value), Gibbs free energy (negative value) in addition to high value of entropy shows the endothermic and spontaneous nature of sorption process. Following the optimization of variables, the adsorption process follows the intraparticle kinetic model with R2 of 0.98 and the Langmuir isotherm with high correlation coefficient (R2 > 0.95). The procedure was applied for the analytes determination in the food samples with satisfactory results (recoveries >95% and relative standard deviation’s (RSD) lower than 4%). [ABSTRACT FROM AUTHOR]

A new complex based on chlorendic acid (HET), [Cd8(HET)8(DMF)4(H2O)12] ·8DMF ( 1) was synthesized by liquid evaporate method from the mixture of HET and Cd(NO3)2 ·4H2O. Single crystal X-ray analysis reveals that the structure of complex 1 features a one-dimensional (1D) wave chain that is further assembled into three-dimensional (3D) framework directed by supramolecular interactions, including hydrogen bond, Cl ···Cl halogen bond, and so on. To the best of our knowledge, this is the first metal-organic coordination polymer based on chlorendic acid (HET). The luminescent property and thermal stability of complex 1 were also discussed. [ABSTRACT FROM AUTHOR]

A new fluorescent chemosensor1, which based on hydroxyapatite (HA) nanoparticles covalently functionalized with a difluoroboron dipyrromethene, has been prepared by nucleophilic substitution of the fluorescent dye 3-chloro-4,4-difluoro-8-(4-tolyl)-5-[bis(pyridine2-ylmethyl)amino]-4-bora-3a,4a-diaza-s-indacene (2) with surface-modified HA nanoparticles. The HA particles were prepared by using SiO2as templates (THA) with 3-(aminopropyl)triethoxysilane (THA-APTES). Substitution of the electron-withdrawing chlorine in2by an electron-donating amino group of HA changes the properties of the nanoparticles1and the corresponding fluorescent dye2. Absorption and emission maxima of1in ethanol are red-shifted by 75 and 30 nm, respectively, in comparison with those of2. In contrast to no selectivity of dye2for Cd2+or Zn2+in EtOH/H2O (95/5 V/V) solutions, the nanofluorescent probe1forms 1 : 1 complexes with Cd2+or Zn2+, producing an instant color change along with largehypsochromicshifts in the absorption and fluorescence spectra by 70 and 35 nm, respectively, and large cation-induced fluorescence amplifications. [ABSTRACT FROM AUTHOR]

Until now, the determination of Cd at trace levels in aqueous samples by TXRF has been restricted. When Mo-target X-ray tubes are used, low sensitivity and interferences with Cd L-lines used for quantification prevent trace analysis. Alternatively, when W-target X-ray tubes are used Cd excitation is limited. For this reason, a sample pretreatment is usually necessary to extract, isolate and concentrate Cd prior to TXRF analysis. In the present contribution, the feasibility of a dispersive liquid-liquid microextraction approach (DLLME) combined with TXRF for ultratrace Cd determination in different types of environmental waters is shown. Parameters affecting the extraction procedure and TXRF measurement conditions have been carefully evaluated to ensure the highest sensitivity for Cd determination. Using the best analytical conditions, it was found that the minimum cadmium content that could be detected in an aqueous solution was 0.04 μg L−1. This value is more than two orders of magnitude lower compared with the direct TXRF analysis of Cd in aqueous samples. The precision of the methodology was evaluated in terms of relative standard deviation (RSD) of six replicate analyses of a standard solution containing 3 μg L−1. The precision of the method was determined to be approximately 5% RSD. In order to test the suitability of the method when dealing with complex matrices as well as the influence of interfering ions, the determination of Cd in spiked water samples (sea water, estuarine water and river water) at the levels of 1 μg L−1 and 5 μg L−1 was undertaken and Cd added to the samples was quantitatively determined. Our results give insight into the possibilities of the combination of DLLME and TXRF for ultratrace Cd determination in different types of environmental waters. [ABSTRACT FROM AUTHOR]

Abstract: In this study, two novel three-dimensional (3D) supramolecular networks, [Cd(BIM)2(SO4)(H2O)]·(C2H5OH) (H2O)2 (1) and [Cd(2-mBIM)(SO4)(H2O)3]·H2O (2) [BIM=bis(imidazol-1-yl)-methane, 2-mBIM=bis(2-methylimidazol-1-yl)methane], were synthesized by the reactions of CdSO4 with BIM or 2-mBIM ligand via solvent diffusion methods. The networks were then characterized by elemental analyses, IR, TGA, and X-ray diffraction. Both compounds 1 and 2 have a 3D hydrogen-bonding network with an infinite one-dimensional (1D) double chain structure and an infinite 1D helix channel, respectively. These results suggest that the subtle change in the ligand structure may have a strong influence on the resulting architectures of the metal–organic frameworks. The solid-state luminescent spectra of compounds 1 and 2 indicate weak fluorescent emissions at ca. 338 and 389nm, respectively. [Copyright &y& Elsevier]

Colloidal CdTe quantum wires are reported having ensemble photoluminescence efficiencies as high as 25% under low excitation-power densities. High photoluminescence efficiencies are achieved by formation of a monolayer CdS shell on the CdTe quantum wires. Like other semiconductor nanowires, the CdTe quantum wires may contain frequent wurtzite-zinc-blende structural alternations along their lengths. The present results demonstrate that the optical properties, emission-peak shape and photoluminescence efficiencies, are independent of the presence or absence of such structural alternations. [ABSTRACT FROM AUTHOR]

Monkey metallothionein α domain tandem repeats (4mMTα), which exhibit high cadmium affinity, have been displayed for the first time on the surface of a bacterium using ice nucleation protein N-domain ( inaXN) protein from the Xanthomonas campestris pv (ACCC-10049) as an anchoring motif. The shuttle vector pIME, which codes for INAXN-4mMTα-EGFP fusion, was constructed and used to target 4mMTα and EGFP on the surface of Pseudomonas putida X4 (CCTCC-209319). The surface location of the INAXN-4mMTα-EGFP fusion was further verified by western blot analysis and immunofluorescence microscopy. The growth of X4 showed resistance to cadmium presence. The presence of surface-exposed 4mMTα on the engineered strains was four times higher than that of the wild-type X4. The Cd accumulation by X4/pIME was not only four times greater than that of the original host bacterial cells but was also remarkably unaffected by the presence of Cu and Zn. Moreover, the surface-engineered strains could effectively bind Cd under a wide range of pH levels, from 4 to 7. P. putida X4/pIME with surface-expressed 4mMTα-EGFP had twice the cadmium binding capacity as well as 1.4 times the fluorescence as the cytoplasmic 4mMTa-EGFP. These results suggest that P. putida X4 expressing 4mMTα-EGFP with the INAXN anchor motif on the surface would be a useful tool for the remediation and biodetection of environmental cadmium contaminants. [ABSTRACT FROM AUTHOR]

On the basis of the spectral line intensity relaxation during the plasma decay, fifty six spectral lines between 219 nm and 330 nm in the cadmium (Cd) spectrum were identified as Cd III (doubly ionized) or Cd IV (triply ionized) lines. The measured Stark widths of twelve, the most intense spectral lines around 315 ±15 nm with well defined profiles, are presented. Investigated spectral lines originate from the high lying energy levels, not classified up to now. A linear low-pressure pulsed arc was used as an optically thin plasma source. A pulsed discharge was produced in a pyrex discharge tube. Helium was chosen as the carrier gas. The cadmium atoms were sputtered from the thin cadmium cylindrical plates located in the homogeneous axial part of the discharge tube. The helium plasma was operated at electron temperatures up to 19 000 K and 1.1 × 10 m electron density. The stepwise ionization processes via the high lying singly ionized (Cd II) energy levels, populated well due to the Penning and charge exchange effects, provide high density of the Cd III (and Cd IV) ions in our helium plasma. The temporal evolutions of the spectral line intensities were monitored using a spectrograph and an ICCD camera as a highly sensitive detection system. [ABSTRACT FROM AUTHOR]

CdS/Titanate nanotubes (TNTs) were successfully synthesised by a simple, rapid, and reliable microwave hydrothermal method. The CdS nanoparticles synthesised using a 140-W microwave irradiation power at 423 K photodegraded 26% ammonia in water, while the photocatalytic efficiency increased to 52.3% using the synthesised CdS/TNTs composites. The results indicated that the CdS/TNTs photocatalysts possess improved photocatalytic activity than that of CdS or TNTs materials alone. [ABSTRACT FROM AUTHOR]

new simple and inexpensive optical chemical sensor for cadmium(II) ions is presented. The cadmium sensing system was prepared by incorporating 2-amino-cyclopentene-1-dithiocarboxylic acid ( ACDA) on a triacetylcellulose membrane. The absorption spectra of the optical sensor membrane in Cd(II) solution showed a maximum peak at 430 nm. The proportionality in intensity of the membrane color on the optode to varying amounts of Cd(II) suggests its potential applications for screening Cd(II) in aqueous samples by visual colorimetry. The sensor provided a wide concentration range of 3.0 × 10-3.4 × 10 M of Cd(II) ions with a detection limit of 1.0 × 10 M (0.2 μg/mL). The relative standard deviations for eight replicate measurements of 8.0 × 10 and 5.0 × 10 M Cd(II) were 2.7 and 2.3%, respectively. The response time of the optode was 6 min. The influence of interfering ions on the determination of 1.0 × 10 M Cd(II) was studied and the main interferences were removed by extraction method. The sensor was applied to the determination of Cd(II) in water samples. [ABSTRACT FROM AUTHOR]

Cadmium concentration in durum ( Triticum durum L.) grain may be influenced by fertilizer management. A three year field study was conducted at two locations in southwestern Manitoba, Canada, to determine the effect of source, timing and placement of N fertilizer on grain Cd concentration of durum wheat under reduced-tillage (RT) and conventional-tillage (CT) management. There was a significant year-to-year variation in grain yield and grain Cd concentration, indicating a strong effect of environment on phytoavailability of Cd. Soil type also had a dominating effect on Cd in durum grain. Grain Cd concentration and accumulation were always lower at the Newdale clay loam (CL) location than the Stockton fine sandy loam (FSL) location. Compared to CT, RT management decreased grain Cd concentration and accumulation. Application of N fertilizer significantly increased grain Cd concentration and decreased grain Zn concentration. The increase in grain Cd could be due to the increasing Cd concentration in soil solution, the improved crop growth, or a competitive interaction between Cd and Zn for binding sites in the soil system and for uptake sites in the roots, following the application of N fertilizer. Time, source and placement of N fertilization showed inconsistent effect on grain yield and grain Cd concentration. The effects when observed were minor compared to effects of year and soil type on grain Cd concentration. Application of anhydrous ammonia (NH) generally resulted in higher Cd concentration in durum grain than application of same level of other N sources including urea ammonium nitrate (UAN), urea and ammonium nitrate (AN), probably due to greater N efficiency from the NH as compared to the other sources. Where differences due to placement occurred, banded application of fertilizers generally resulted in higher Cd concentration in durum grain than did dual-banded placement, indicating a higher fertilizer availability. Soil type, year and N fertilization greatly affected concentration of Cd in durum grain. Selection of a suitable source, timing and placement combination of N fertilization is important in optimizing crop yield and minimizing grain Cd concentration. [ABSTRACT FROM AUTHOR]

In rice ( Oryza sativa L.), cadmium (Cd), a toxic heavy metal, is found in phloem sap and eventually accumulates in the grains. To further characterize phloem-transported Cd, the chemical forms of Cd and other metals and varietal differences in phloem sap Cd concentrations were investigated in young rice plants. The size-exclusion chromatography elution times for Cd-bound compounds indicated that phloem Cd in cv. Nipponbare exists mainly as an approximately 13 kDa complex. Protease digestion of rice phloem sap reduced the bound Cd content from 92 to 19%. The remaining Cd may bind to low-molecule SH compounds. An experiment examining in vitro addition of Cd to phloem sap from non-Cd-treated plants revealed that rice phloem sap constitutively contains Cd chelators. The major Cd peak is distinguishable from those of Fe, Zn, Cu, Mn, Ni and Co, which probably bind to nicotianamine, 2′-deoxymugineic acid, citrate and histidine. The Cd concentrations of the phloem saps in three varieties (Milyang 23, LAC 23 and Koshihikari) grown under the same soil conditions were correlated with their grain Cd concentrations, which had been reported previously, whereas the concentrations of the xylem saps were not. In conclusion, rice phloem sap Cd differs from other metals as it may bind to a novel approximately 13 kDa protein and SH compounds, and the concentration of Cd in rice phloem sap may be a key determinant of its grain content. [ABSTRACT FROM AUTHOR]

To investigate the effects of cadmium (Cd) on photosynthetic and antioxidant activities of safflower ( Carthamus tinctorius L.) plants, two cultivars (Yuming and New safflower No. 4) were used for long-term pot experiment, under 0, 25, 50 or 100 mg Cd kg (DW) soil conditions. The results showed that there is a large amount of Cd (148.6–277.2 mg kg) accumulated in the shoot of safflower, indicating this species might be a potential Cd accumulator. Exposure to 25–100 mg Cd kg soil decreased the net photosynthetic rate by 25.6%–48.9% for New safflower No. 4, and 16.7%–57.3% for Yuming, respectively. The inhibition of photosynthesis might result from the limitation of stomatal conductance, reduction in photosynthetic pigment, and destruction of photosynthetic apparatus caused by Cd stress. Cd caused an enhancement of malondialdehyde (MDA), an increase in activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX), and a decrease in catalase (CAT) activity for both cultivars. It seems that SOD and APX accounted for the scavenging of oxidant stress in safflower cultivars. The physiological response of safflower plants to Cd stress was cultivar- and dose- dependent. New safflower No. 4 exhibited high photosynthetic performance at high Cd stress, which may be contributed by high intercellular CO concentration, APX activity and Car/Chl ratio. In contrast, Yuming is more tolerant to Cd toxicity at low Cd level, in which an efficient antioxidant system is involved. [ABSTRACT FROM AUTHOR]

Abstract: An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90µg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700µg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd Kα intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1σ) and the results deviated from the expected values by <4% on average. [Copyright &y& Elsevier]