RESUMEN
Nickel nanoparticle decorated graphene (GP-Ni) is prepared by one-pot hydrothermal reduction of graphene oxide and nickel cations by hydrazine hydrate in the presence of poly(sodium-p-styrenesulfonate) (PSS). The GP-Ni hybrid is characterized by XRD, TEM, SEM, XPS, Raman and FT-IR spectra, demonstrating the formation of poly-dispersed nickel nanoparticles with an average size of 83 nm attached on the surface of graphene sheets. The GP-Ni hybrid exhibits ferromagnetic behavior with a magnetization saturation of 31.1 emu g(-1) at 10,000 Oersted (Oe). The GP-Ni also possesses favorable stability in aqueous medium and rapid magnetic response to an external magnetic field. These make it a novel magnetic adsorbent for the separation/isolation of His6-tagged recombinant proteins from a complex sample matrix (cell lysate). The targeted protein species is captured onto the surface of the GP-Ni hybrid via specific metal affinity force between polyhistidine groups and nickel nanoparticles. The SDS-PAGE assay indicates highly selective separation of His6-tagged Smt A from cell lysate. The GP-Ni hybrid displays favorable performance on the separation/isolation of His6-tagged recombinant proteins with respect to the commercial NTA-Ni(2+) column.
Asunto(s)
Grafito/química , Histidina/metabolismo , Nanopartículas del Metal/química , Níquel/química , Proteínas Recombinantes de Fusión/aislamiento & purificación , Electroforesis en Gel de Poliacrilamida , Escherichia coli/metabolismo , Nanopartículas del Metal/ultraestructura , Espectroscopía de Fotoelectrones , Espectrometría por Rayos X , Espectrometría Raman , Temperatura , Difracción de Rayos XRESUMEN
Considerable analytical methods have been developed for arsenic speciation in the last 5 years, the details of these new arsenic speciation procedures are thus summarized in present mini review. The performances of various sample pretreatment techniques including solid phase extraction, liquid-liquid extraction, hydride generation, liquid chromatography and capillary electrophoresis, which offer effective preconcentration/separation and eventually contribute greatly to excellent sensitivity and selectivity in arsenic speciation when coupling with suitable detection mode, are discussed and compared thoroughly. High-performance liquid chromatography coupling with inductively coupled plasma mass spectrometry and hydride generation atomic spectrometry are proved to be the most powerful hyphenated methodologies for arsenic speciation in environmental and biological matrices.