Description:    In the present study, a novel synthesized adsorbent material based on 3-mercaptopropyltrimethoxysilane-functionalized multi-walled carbon nanotubes was used to increase the Pb 2+ adsorption from aqueous solutions in a flow injection solid-phase extraction system coupled to flame atomic absorption spectrometry. Spectroscopic and microscopic techniques (Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and scanning electron microscopy) were employed to confirm the chemical modification of the adsorbent surface. Preconcentration conditions (sample pH, flow rate, buffer solution, and eluent concentrations) were optimized using factorial and Doehlert matrix designs that made it possible to construct a linear graph in the 5.0- to 130.0-μg L −1 range ( r  = 0.9999) and estimate detection and quantification limits (1.7 and 5.7 μg L −1 , respectively). The method precision was found to be 4.20 and 1.97 % for 5.0 and 100.0 μg L −1 Pb 2+ solutions, respectively. When using the 3-mercaptopropyltrimethoxysilane-functionalized multi-walled carbon nanotubes, the sensitivity for the Pb 2+ trace determination was improved to 95 % compared with the oxidized multi-walled carbon nanotubes, thus evidencing the significant enhancement of the adsorption capacity. The developed method was successfully applied to the analysis of Pb 2+ species in different water samples and the PACS-2 marine sediment-certified reference material. Content Type Journal Article Pages 1-13 DOI 10.1007/s11270-012-1341-z Authors Bruna Fabrin Somera, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil Marcela Zanetti Corazza, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil Maria Josefa Santos Yabe, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil Mariana Gava Segatelli, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil Evgeny Galunin, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil César Ricardo Teixeira Tarley, Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, Universidade Estadual de Londrina (UEL), PR 445 Km 380, Londrina, PR 86050-482, Brazil Journal Water, Air, & Soil Pollution Online ISSN 1573-2932 Print ISSN 0049-6979