Highly selective and sensitive nanomaterials for the detection of heavy metal ions (HMIs) hold a key to electroanalysis. As reported, various works have been adopted to detect Pb(II). However, how to improve the selectivity and sensitivity of sensing Pb(II) without interference is still a huge challenge.

Recently, IIM researchers have found a detection method that different adsorption toward HMIs will result in diverse electrochemical responses. With the consideration of this, the tri-metaliron-based LDH materials with high adsorption ability and enhanced physicochemical properties are constructed as a sensing interface for the detection of Pb(II).

In a paper published in Journal of Hazardous Materials (http://www.sciencedirect.com/science/journal/03043894), a study team led by Prof. HUANG Xingjiu from Institute of Intelligent Machines, developed the selective electrochemical detection of Pb(II) with nano-Fe/Mg/Ni ternary layered double hydroxide (Fe/Mg/Ni-LDH).

They describe that Pb(II) can be detected by Fe/Mg/Ni ternary LDH modified GCE selectively using SWASV. The sensitivity is 68.1 μA μM^-1 over the range from 0.03 to 1.0 μM and the limit of detection is 0.032 μM under the optimized conditions.

The formation of M-O-Pb (M=Fe, Mg, Ni) is contribute to the high adsorption capacity of Fe/Mg/Ni-LDH toward Pb(II), resulting in the high sensitivity in electrochemistry detection. Furthermore, the selective adsorption to Pb(II) proved by X-ray photoelectron spectroscopy(XPS) should be responsible for the selective detection.

Actually, this finding establishes the combination of the adsorption of nanomaterials with electrochemical performance toward HMIs. Meanwhile, this work is meaningful for achieving the selective and sensitivity for HMIs detection by using layered double hydroxide.

This work was supported financially by the National Natural Science Foundation of China and the Interdisciplinary Innovation Team of the Chinese Academy of Sciences, China.

Schematic of the competitive adsorption and selective detection of Pb(II).