In a paper published last week, HUANG Xingjiu's study team at Institute of Intelligent Machines, Hefei Institutes of Physcial Science developed selective electrochemical detection of Pb(II) with nano-Fe/Mg/Ni ternary layered double hydroxide (Fe/Mg/Ni-LDH).

Highly selective and sensitive nanomaterials to detect heavy metal ions (HMIs) plays a key role in electroanalysis. According to previous reports, much effort was devoted to Pb(II) detection, however the huge challenges remain in improving the selectivity and sensitivity of sensing Pb(II) without interference.

Given this, the team has found a detection method that different adsorption toward HMIs results in diverse electrochemical responses.

Considering this, the tri-metal iron-based LDH materials with high adsorption ability and enhanced physicochemical properties are constructed as a sensing interface for the detection of Pb(II).

Herein, they report that Pb(II) could be detected by Fe/Mg/Ni ternary LDH modified GCE selectively using square wave anodic stripping voltammetry (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) contributes to the high adsorption capacity of Fe/Mg/Ni-LDH toward Pb(II), and thus results 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 relationship between the adsorption of nanomaterials and electrochemical performance toward HMIs. Meanwhile, this work is of great importance to achieve the selective and sensitive 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). (Image by LI Shanshan)