Dual-channel molecularly imprinted sensor based on dual-potential electrochemiluminescence of Zn-MOFs for double detection of trace chloramphenicol

Abstract

Functionalized metal organometallic frameworks (MOFs) offer unique advantages in the field of sensing due to their versatility and tunable optical properties. In this work, a new dual-potential electrochemiluminescence (ECL) molecularly imprinted sensor using single Zn-MOF signal probe was designed for double detection of trace chloramphenicol (CAP). As dual-signal ECL emitters, Zn-MOFs were firstly modified on the electrode, showing excellent ECL emission in both cathodic and anodic potential. Then the molecularly imprinted polymer (MIP) was electrochemically prepared using o-phenylenediamine (O-PD) and CAP as a template molecule on the Zn-MOFs/electrode. After CAP as a molecular recognition element was eluted and removed from the Zn-MOFs/MIP/electrode, a new ECL sensor was developed for CAP detection by re-adsorption of CAP on the MIP, resulting in “off” of ECL signal. Compared with the conventional single-signal luminophores, Zn-MOFs show more stable and excellent dual ECL signals, which greatly improve the discriminability and accuracy of CAP trace detection. Under the optimal conditions, the linear range of CAP detection was 1 × 10-14−1 × 10-8 M, and the minimum limits of detection (LOD) were 2.1 fM and 2.5 fM for cathode and anode ECL, respectively. This is the first time that Zn-MOFs are used as dual-ECL emitters for molecular sensing systems, and the proposed dual-channel sensing system is flexibly applicable to sensitive detection of other antibiotics, which has broad practical application in food safety.