Uneven distribution of minor metals and migration of isotopes in polymeric material （polypropylene） - originating under certain physical and chemical conditions-could possibly affect the stability and bio-compatibil...Uneven distribution of minor metals and migration of isotopes in polymeric material （polypropylene） - originating under certain physical and chemical conditions-could possibly affect the stability and bio-compatibility of such material. Unusually high levels of embedded surface metal isotopes from migration effects could affect studies such as tissue engineering and biospecific adhesion of cells to polymeric surfaces. There is, therefore, a general need to know the distribution of metal isotopes in such polymeric materials. We have developed an ultrasensitive technique for assessing the isotopic distribution in polymer matrices, and studying migration of metal isotopes. The technique uses laser ablation linked to an ICP-MS instrument. It is semi-quantitative and capable of high-resolution detection over a wide range of elemental levels. Polymers usually contain catalytic residues and other minor metal impurities. Some of the isotopes of these metals migrate to the surface, while others remain embedded deep in the polymeric product. Such unwanted metallic residues and isotopes could be a potential hazard, and ablative laser technology has the ability to study homogeneity of such distributions in the polymer matrix. The aim of this paper, therefore, is to explore the potential of our method for studying isotope migration using suitable polypropylene samples.展开更多
Atmospheric aerosol samples collected in Beijing during 17-21 September 2004 were analyzed using the proton-induced X-ray emissions (PIXE) method,yielding concentrations of 20 elements.Analyzing the aerosol element si...Atmospheric aerosol samples collected in Beijing during 17-21 September 2004 were analyzed using the proton-induced X-ray emissions (PIXE) method,yielding concentrations of 20 elements.Analyzing the aerosol element size-spectrum distribution,enrichment factor (EF) and source over Beijing showed that under strong wind weather conditions,there were double peak distributions in the element size-spectra of Cu,S,K,Mn,As,Br,and Pb:one in fine mode and another in coarse mode.The peak in fine mode resulted from local emissions related to human activities,while the peak in coarse mode was caused by long range transport.The EF values of elements Ni,Cu,Zn,As,Se,Br,and Pb were relatively high,suggesting an evident characteristic polluted by regional aerosol.Results from factor analysis indicated that soil dust,coal-burning,industry and vehicle emissions contributed considerably to the autumn aerosol pollution in Beijing.展开更多
文摘Uneven distribution of minor metals and migration of isotopes in polymeric material （polypropylene） - originating under certain physical and chemical conditions-could possibly affect the stability and bio-compatibility of such material. Unusually high levels of embedded surface metal isotopes from migration effects could affect studies such as tissue engineering and biospecific adhesion of cells to polymeric surfaces. There is, therefore, a general need to know the distribution of metal isotopes in such polymeric materials. We have developed an ultrasensitive technique for assessing the isotopic distribution in polymer matrices, and studying migration of metal isotopes. The technique uses laser ablation linked to an ICP-MS instrument. It is semi-quantitative and capable of high-resolution detection over a wide range of elemental levels. Polymers usually contain catalytic residues and other minor metal impurities. Some of the isotopes of these metals migrate to the surface, while others remain embedded deep in the polymeric product. Such unwanted metallic residues and isotopes could be a potential hazard, and ablative laser technology has the ability to study homogeneity of such distributions in the polymer matrix. The aim of this paper, therefore, is to explore the potential of our method for studying isotope migration using suitable polypropylene samples.
基金supported by the National Basic Research Program of China (No. 2010CB428503)Project of the Beijing Municipal Financial Bureau (No. PXM2008_178305_ 06995)
文摘Atmospheric aerosol samples collected in Beijing during 17-21 September 2004 were analyzed using the proton-induced X-ray emissions (PIXE) method,yielding concentrations of 20 elements.Analyzing the aerosol element size-spectrum distribution,enrichment factor (EF) and source over Beijing showed that under strong wind weather conditions,there were double peak distributions in the element size-spectra of Cu,S,K,Mn,As,Br,and Pb:one in fine mode and another in coarse mode.The peak in fine mode resulted from local emissions related to human activities,while the peak in coarse mode was caused by long range transport.The EF values of elements Ni,Cu,Zn,As,Se,Br,and Pb were relatively high,suggesting an evident characteristic polluted by regional aerosol.Results from factor analysis indicated that soil dust,coal-burning,industry and vehicle emissions contributed considerably to the autumn aerosol pollution in Beijing.
