A novel copper(i) metal–organic framework as a highly efficient and ultrasensitive electrochemical platform for detection of Hg(ii) ions in aqueous solution

Abstract

The selective detection of toxic Hg(II) ions is of great significance for industrial processing and environmental remediation. Herein, a novel copper(I) metal–organic framework [Cu₃Cl₃(bimpy)₃] (1) (bimpy = 3,5-bis(1-imidazolyl)pyridine) was constructed by a solvothermal method. Single-crystal X-ray analysis shows that complex 1 is a 2-fold interpenetrated three-dimensional structure with a tfj topology, exhibiting high thermal stability and water stability. Complex 1 was used to modify a glassy carbon electrode (GCE) for the determination of Hg(II) in 0.1 M phosphate buffer solution (PBS) at pH = 7.0. However, on account of the poor electron-conductive property of complex 1, acetylene black (AB) was introduced into complex 1 to improve its electrochemical sensing activity. The electrochemical sensing property of AB and the complex 1 modified GCE was investigated by cyclic voltammetry and chronoamperometric tests. Under the optimal conditions, AB/complex 1/GCE exhibits a high sensitivity of 16.85 μA μM⁻¹ cm⁻² and a low limit of detection of 1.01 nM in the wide linear range from 2.0 μM to 64 μM. AB/complex 1/GCE could also be applied for detecting Hg(II) ions in tap water and river water. The aptasensor provides a valuable tool with satisfactory anti-interference, reproducibility, repeatability, simple preparation, and satisfactory applicability for the sensing of Hg(II) ions.