title: Cellulose microfiber functionalized with N,N'-bis (2-aminoethyl)-1,2-ethanediamine as a solid sorbent for the fast preconcentration of Cd(II) in flow system analysis.
abstract: The present paper describes the synthesis of a new chemically modified cellulose microfiber through oxidation with sodium periodate and functionalization with N,N'-bis (2-aminoethyl)-1,2-ethanediamine for the fast and selective preconcentration of Cd(II) ions in flow system analysis. The new sorbent was characterized by FTIR, SEM, and surface area values. The uptake behavior of Cd(II) ions onto this sorbent was evaluated from kinetic data, pseudo-first-order and pseudo-second-order models, as well as from Langmuir, Freundlich and Langmuir-Freundlich adsorption isotherms. The maximum sorption capacity of 4.59 mg g(-1) was estimated by the Langmuir-Freundlich model with fast kinetics for the sorption of Cd(II) described by the pseudo-second-order kinetic model. After characterization, the sorbent was packed in a mini-column, and a fast flow injection preconcentration system for Cd(II) determination by FAAS was developed. The best Cd(II) preconcentration condition, obtained by means of factorial design and response surface methodology, was achieved at pH 9.36 and a flow rate of 10 mL min(-1) followed by elution with 1.0 mol L(-1) nitric acid. By using 78 s preconcentration time, fast and highly sensitive determination of Cd(II) ions could be achieved with a limit of quantification of 0.20 μg L(-1), preconcentration factor of 26, consumption index of 0.5 mL, concentration efficiency of 20 min(-1), and sample throughput of 39 h(-1). The repeatability for 10 replicate determinations was found to be 7.8 and 2.5% for Cd(II) ion concentrations of 5.0 and 100.0 μg L(-1), respectively. The new sorbent efficiency for the interference-free preconcentration of Cd(II) ions was assessed by analysis of tap, mineral and lake waters, as well as synthetic seawater and normal saline waters. Furthermore, complex samples, such as biological samples, could be analysed by the proposed method in accordance with the accuracy attested by analysis of certified reference materials, TORT-2 (lobster hepatopancreas), and DOLT-4 (dogfish liver).
authors.affiliation: Universidade Estadual de Londrina (UEL), Departamento de Química, Centro de Ciências Exatas, Rodovia Celso Garcia Cid, PR 445 Km 380, CEP 86050-482 Londrina, PR, Brazil.
authors.forename: Fernanda Midori
authors.initials: FM
authors.lastname: de Oliveira
authors.forename: Bruna Fabrin
authors.initials: BF
authors.lastname: Somera
authors.forename: Marcela Zanetti
authors.initials: MZ
authors.lastname: Corazza
authors.forename: Maria Josefa Santos
authors.initials: MJ
authors.lastname: Yabe
authors.forename: Mariana Gava
authors.initials: MG
authors.lastname: Segatelli
authors.forename: Emerson Schwingel
authors.initials: ES
authors.lastname: Ribeiro
authors.forename: Eder Cláudio
authors.initials: EC
authors.lastname: Lima
authors.forename: Silvio Luís Pereira
authors.initials: SL
authors.lastname: Dias
authors.forename: César Ricardo Teixeira
authors.initials: CR
authors.lastname: Tarley