title: The isolation of basic proteins by solid-phase extraction with multiwalled carbon nanotubes.
abstract: Multiwalled carbon nanotubes (MWCNTs) have been employed for the first time as sorbents for the isolation of basic proteins from other protein species in biological sample matrices by solid-phase extraction (SPE). A microcolumn packed with MWCNTs was incorporated after appropriate pretreatment into a sequential injection system, which facilitates online selective sorption of basic protein species (hemoglobin and cytochrome c in this particular case). The retained protein species were afterwards separated from each other by sequential elution from the microcolumn through the employment of appropriate eluents. A 0.025 mol L(-1) phosphate buffer solution of pH 8.0 facilitated the efficient collection of hemoglobin, while a 0.5 mol L(-1) NaCl solution ensured the quantitative recovery of the retained cytochrome c. With a sample loading volume of 2.0 mL, enrichment factors of 11 and 15 were derived for hemoglobin and cytochrome c, along with retention efficiencies of 100% for both species and recovery rates of 98 and 90%, respectively. A sampling frequency of 8 h(-1) was achieved, and the precisions were 3.0% and 0.8% (RSD) for hemoglobin and cytochrome c at a concentration of 5.0 microg mL(-1). The practical applicability of this system was demonstrated by processing of human whole blood for isolation of hemoglobin, and satisfactory results were obtained by assay with SDS-PAGE.
authors.affiliation: Research Center for Analytical Sciences, Box 332, Northeastern University, Shenyang 110004, China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Du
authors.forename: Yong-Liang
authors.initials: YL
authors.lastname: Yu
authors.forename: Xu-Wei
authors.initials: XW
authors.lastname: Chen
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Wang
mesh_terms: D006863:Hydrogen-Ion Concentration; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D052616:Solid Phase Extraction
chemical_list: D037742:Nanotubes, Carbon; D011506:Proteins