title: Direct extraction of lead (II) from untreated human blood serum using restricted access carbon nanotubes and its determination by atomic absorption spectrometry.
abstract: Oxidized carbon nanotubes were covered with layers of bovine serum albumin to result in so-called restricted-access carbon nanotubes (RACNTs). This material can extract Pb(2+) ions directly from untreated human blood serum while excluding all the serum proteins. The RACNTs have a protein exclusion capacity of almost 100% and a maximum Pb(2+) adsorption capacity of 34.5mg g(-1). High resolution transmission electron microscopy, scanning transmission electron microscopy and energy dispersive spectroscopy were used to confirm the BSA layer and Pb(2+) adsorption sites. A mini-column filled with RACNTs was used in an on-line solid phase extraction system coupled to a thermospray flame furnace atomic absorption spectrometry. At optimized experimental conditions, the method has a detection limit as low as 2.1µg L(-1), an enrichment factor of 5.5, and inter- and intra-day precisions (expressed as relative standard deviation) of <8.1%. Recoveries of the Pb(2+) spiked samples ranged from 89.4% to 107.3% for the extraction from untreated human blood serum.
authors.affiliation: Laboratory of Toxicant and Drug Analyses, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil; Institute of Chemistry, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil.
authors.forename: Valéria Maria Pereira
authors.initials: VM
authors.lastname: Barbosa
authors.affiliation: Laboratory of Toxicant and Drug Analyses, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil; Institute of Chemistry, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil.
authors.forename: Adriano Francisco
authors.initials: AF
authors.lastname: Barbosa
authors.affiliation: Brazilian Nanotechnology National Laboratory, 13083-970 Campinas, SP, Brazil.
authors.forename: Jefferson
authors.initials: J
authors.lastname: Bettini
authors.affiliation: Institute of Chemistry, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil.
authors.forename: Pedro Orival
authors.initials: PO
authors.lastname: Luccas
authors.affiliation: Laboratory of Toxicant and Drug Analyses, Federal University of Alfenas - Unifal-MG, Gabriel Monteiro da Silva Street 700, 37130-000 Alfenas, MG, Brazil. Electronic address: eduardocfig@yahoo.com.br.
authors.forename: Eduardo Costa
authors.initials: EC
authors.lastname: Figueiredo
mesh_terms: D000327:Adsorption; D004785:Environmental Pollutants / Q000097:blood* / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D007854:Lead / Q000097:blood* / Q000737:chemistry; D046529:Microscopy, Electron, Transmission / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D013054:Spectrophotometry, Atomic
chemical_list: D004785:Environmental Pollutants; D037742:Nanotubes, Carbon; D007854:Lead
keywords: Atomic absorption spectrometry; Carbon nanotubes; Lead; Restricted access carbon nanotubes; Restricted access material; Serum