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.
Talanta. 2011 Oct 15;85(5):2417-24. doi: 10.1016/j.talanta.2011.07.088. Epub 2011 Jul 30.
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).
本文描述了一种新的化学改性纤维素微纤维的合成，该纤维通过高碘酸钠氧化和 N,N'-双（2-氨基乙基）-1,2-乙二胺功能化，用于流动系统分析中 Cd(II)离子的快速和选择性预富集。新的吸附剂通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和表面积值进行了表征。从动力学数据、准一级和准二级模型以及 Langmuir、Freundlich 和 Langmuir-Freundlich 吸附等温线评估了 Cd(II)离子在该吸附剂上的吸附行为。通过 Langmuir-Freundlich 模型估计最大吸附容量为 4.59mg g(-1)，动力学快速，吸附 Cd(II)的准二级动力学模型描述。在表征之后，将吸附剂填充在微型柱中，并开发了用于 FAAS 测定 Cd(II)的快速流动注射预浓缩系统。通过析因设计和响应面方法获得的最佳 Cd(II)预浓缩条件是在 pH 9.36 和流速为 10 mL min(-1)下实现的，然后用 1.0 mol L(-1)硝酸洗脱。通过使用 78 s 的预浓缩时间，可以实现 Cd(II)离子的快速和高灵敏度测定，检出限为 0.20μg L(-1)，预浓缩因子为 26，消耗指数为 0.5 mL，浓缩效率为 20 min(-1)，样品通量为 39 h(-1)。对于 5.0 和 100.0μg L(-1)的 Cd(II)离子浓度，重复测定 10 次的重复性分别为 7.8%和 2.5%。通过分析自来水、矿泉水和湖水以及合成海水和生理盐水，评估了新吸附剂对 Cd(II)离子无干扰预浓缩的效率。此外，还可以通过所提出的方法分析复杂样品，例如生物样品，其准确性可以通过分析认证参考物质 TORT-2（龙虾肝胰腺）和 DOLT-4（鲨鱼肝）得到证实。
