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81.
Factorial design in the optimization of preconcentration procedure for lead determination by FAAS 总被引:1,自引:0,他引:1
The present paper proposes a preconcentration procedure for lead determination using flame atomic absorption spectrometry (FAAS). It is based on lead(II) ions extraction as brilliant cresyl blue (BCB) complex and its sorption onto Diaion HP-2MG, a methacrylic ester copolymer. The optimization step was carried out using factorial design and the variables studied were pH, shaking time and reagent concentration. In the established experimental conditions, lead can be determinate with a limit of detection of 3.7 μg L−1 lead (N = 20) and a relative standard deviation of 7% for a lead concentration of 100 μg L−1. The accuracy was confirmed by analysis of a certified reference material, the stream sediment furnished by National Research Centre for Certified Reference Materials (NRCCRM), China (GBW 07310). Effect of other ions in the procedure proposed was also studied. The method was applied for lead determination in real samples of water, tea, soil and dust. Tests of addition/recovery in the experiments for lead determination in water samples revealed that the proposed procedure could be applied satisfactorily for analysis of these samples. 相似文献
82.
T. SuhasiniB.C. Jamalaiah T. ChengaiahJ. Suresh Kumar L. Rama Moorthy 《Physica B: Condensed Matter》2012,407(3):523-527
Different concentrations of Ho3+-doped lead borate titanate aluminum fluoride (LBTAFHo) glasses with chemical composition of PbO-H3BO3-TiO2-AlF3-Ho2O3 were prepared by the melt quenching method. The spectral properties were investigated using the absorption, emission and decay measurements. The experimental oscillator strengths were calculated from the area under the absorption bands. Applying Judd-Ofelt theory, the intensity parameters (Ωλ=2, 4, 6) were calculated, by the least square fit approach from which the radiative transition rates, luminescence branching ratios and radiative decay times were determined. The photoluminescence spectra revealed the quenching of luminescence intensity beyond 1.0 mol% of Ho3+ ion concentration. To investigate the luminescence potentiality of 5F4→5I8 emission level, the effective bandwidth and the stimulated emission cross-section were determined. The quenching in experimental decay time is attributed to the resonance energy transfer among the excited Ho3+ ions. 相似文献
83.
C. Barbante C. Turetta G. Capodaglio G. Scarponi 《International journal of environmental analytical chemistry》2013,93(4):457-477
Abstract Differential Pulse Anodic Stripping Voltammetry (DPASV) was applied to determine the lead concentration in recent snow at two sites in the Victoria Land region, East Antarctica. Snow samples were collected during the 6th Italian Scientific Expedition to Antarctica (austral Summer 1990–91) along the wall of 2.5 m-deep hand-dug pits and by coring to a depth of about 11 m. The measurements revealed that lead content in Antarctic snow increased continuously from 1965 (about 3 pg/g) to the early 1980s (maximum about 8 pg/g), after which a marked, rapid decrease took place during the second half of 1980s, down to 2–4 pg/g in 1991. Estimates of the lead contributions from rocks and soils, volcanoes and the marine environment, together with analysis of statistical data on non-ferrous metal production and gasoline consumption, and the corresponding lead emissions into the atmosphere of the Southern Hemisphere, show that a net anthropogenic component is present and support the hypothesis that the trend observed in Antarctic snow may be related to lead consumption in gasoline, which firstly was on the rise, then declined owing to the increased use of unleaded gasoline. 相似文献
84.
Wei Jiang Zheng-Long Yang Ding Weng Jun-Wei Wangb Yun-Feng Lu Min-Juan Zhang Zhen-Zhong Yang 《中国化学快报》2014,25(6):849-853
PbTe/SnTe hybrid nanocrystals with designed shape, chemical composition and narrow size distribution were synthesized by an efficient solvothermal approach. This approach enables mass and economical synthesis of PbTe-based nanocrystals. The organic ligands were completely removed by pretreatment with a super-hydride solution, making it possible to fabricate fully dense and robust thermoelectric devices with increased electrical conductivity. 相似文献
85.
《Current Applied Physics》2018,18(2):226-230
This work presents a study of the electronic transport properties of PbSe pellets fabricated starting of PbSe nanostructures that exhibited a flake-like 2D morphology, which were synthesized by the co-precipitation method. Seebeck coefficient measurements revealed that the PbSe sample displays n-type conductivity, a maximum Seebeck coefficient of −512.6 μV/K around 380 K, and that the carriers scattering is dominated by acoustic and optical phonons. The Fermi level dependence on the temperature and the band gap energy are also reported. Interestingly, size-dependent confinement effects due probably to the reminiscent PbSe 2D character could be evidenced. 相似文献
86.
《Journal of Coordination Chemistry》2012,65(18):2966-2973
The complex of 2,6-diacetylpyridinedihydrazone (L) with lead(II) and azide has been characterized by elemental analyses, FTIR, and single-crystal X-ray analysis. The Pb(C9H13N11) (1) crystallized in the monoclinic space group C2/c. The coordination of 1 exhibits a gap around the lead(II), possibly occupied by a stereochemically active electron lone pair on lead(II) resulting in a hemidirected complex. Antimicrobial activity of the complex is higher than the free ligand. 相似文献
87.
《Journal of Coordination Chemistry》2012,65(18):1719-1726
Three new 2,2′-diamino-4,4′-bithiazole (DABTZ) lead(II) complexes were synthesized and characterized by elemental analyses, IR-, 1H-NMR-, and 13C-NMR-spectroscopy. The single crystal X-ray structural analysis of [Pb(DABTZ)(μ-SCN)(μ-NO3)] n shows the complex to be a 1D chain polymer as a result of sequential thiocyanate and nitrate bridging. The Pb atoms are seven-coordinated by two nitrogen atoms of the 2,2′-diamino-4,4′-bithiazole, three nitrate and two thiocyanate ligands. The arrangement of the 2,2′-diamino-4,4′-bithiazole, nitrate and thiocyanate ligands does not suggest a gap in the coordination around the PbII ion, caused by a stereo-active lone pair of electrons on lead(II) where the coordination around the lead atoms is the less common holodirected. 相似文献
88.
《Analytical letters》2012,45(11):2145-2154
Abstract A color test is presented for the purpose of quickly identifying glazed ceramic and/or enameled metalware which releases excessive Pb. Citric acid solution on filter paper is used to extract Pb from the ware and a Pb-sensitive chromogen indicates the presence of Pb on the paper. The quick color test takes approximately 30 min and is useful for screening ware to determine the need for testing by the 24-h method of the Association of Official Analytical Chemists/American Society for Testing and Materials. 相似文献
89.
90.
Chen Chen Xiangheng Niu Yan Chai Hongli Zhao Minbo Lan Yonggang Zhu Gang Wei 《Electroanalysis》2013,25(6):1446-1452
This work presents a disposable bismuth‐antimony film electrode fabricated on screen‐printed electrode (SPE) substrates for lead(II) determination. This bismuth‐antimony film screen‐printed electrode (Bi‐SbSPE) is simply prepared by simultaneously in situ depositing bismuth(III) and antimony(III) with analytes on the homemade SPE. The Bi‐SbSPE can provide an enhanced electrochemical stripping signal for lead(II) compared to bismuth film screen‐printed electrodes (BiSPE), antimony film screen‐printed electrodes (SbSPE) and bismuth‐antimony film glassy carbon electrodes (Bi‐SbGC). Under optimized conditions, the Bi‐SbSPE exhibits attractive linear responses towards lead(II) with a detection limit of 0.07 µg/L. The Bi‐SbSPE has been demonstrated successfully to detect lead in river water sample. 相似文献