Department of Chemistry, Payame Noor University (PNU), P.O. Box 76175-559, Kerman, Iran.
Analyst. 2010 Jul;135(7):1686-90. doi: 10.1039/c0an00115e. Epub 2010 May 11.
The present work is focused on the modification of multiwalled carbon nanotubes with a ligand, 1-(2-pyridylazo)-2-naphthol (PAN), and its potential application for the development of a new, simple and selective modified glassy carbon electrode for stripping voltammetric determination of Pb(II). The electrochemical method is based on closed circuit accumulation of lead ions onto a PAN-modified multiwalled carbon nanotube electrode from 0.1 mol L(-1) oxalate buffer solution (pH = 3.0) during 150 s at the potential of -0.9 V, following by differential pulse anodic stripping voltammetric determination in the range -0.9 to -0.35 V. The analytical curve for Pb(II) ions covers a linear range varying from 0.8 up to 220.4 microg L(-1). The limit of detection was found to be 0.1 microg L(-1), while the relative standard deviation (RSD) at 50.0 microg L(-1) was 1.8% (n = 5). Many of the coexisting ions had little or no effect on the determination of lead(II). The results suggest that the proposed method can be applied as a simple and efficient alternative technique for the determination of lead ions which has good accuracy in real samples such as natural waters and standard alloys. In addition, this method demonstrates the powerful application of carbon nanotubes in the field of mercury-free electrodes in voltammetric stripping analysis.
本工作主要集中在多壁碳纳米管与配体 1-(2-吡啶偶氮)-2-萘酚（PAN）的修饰及其在开发新型、简单和选择性的修饰玻碳电极方面的潜在应用，用于溶出伏安法测定 Pb(II)。电化学方法基于在 -0.9 V 下，从 0.1 mol L(-1)草酸盐缓冲溶液（pH = 3.0）中通过闭路累积 150 s 将 Pb(II)离子吸附到 PAN 修饰的多壁碳纳米管电极上，随后在 -0.9 至 -0.35 V 的范围内进行差分脉冲阳极溶出伏安法测定。Pb(II)离子的分析曲线涵盖了从 0.8 到 220.4 μg L(-1)的线性范围。检测限为 0.1 μg L(-1)，而在 50.0 μg L(-1)时的相对标准偏差（RSD）为 1.8%（n = 5）。许多共存离子对铅(II)的测定影响很小或没有影响。结果表明，该方法可作为一种简单有效的替代技术，用于测定天然水和标准合金等实际样品中的铅离子，具有良好的准确性。此外，该方法证明了碳纳米管在无汞电极领域在溶出伏安分析中的强大应用。
