ZIF-67/PEDOT modified carbon paper electrode for sensitive electrochemical determination of chlorogenic acids

The design of efficient electrocatalysts for the determination of chlorogenic acids (CGA) is crucial in the biological and medical fields. In this paper, ZIF-67/poly(3,4-ethylenedioxythiophene) (PEDOT) nanocomposites were synthesised. The introduction of PEDOT increased the electrical conductivity of the ZIF-67/PEDOT composites, inhibited the Co atom agglomeration, led to the exposure of more active sites and increased the transport channels. An ultrasensitive CGA sensor based on ZIF-67/PEDOT nanocomposite modified carbon paper (CP) electrode was developed. The nanomaterials were characterised using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrochemical properties of the modified CP electrode. In addition, the effects of different experimental conditions such as pH, scan rate and concentration on the peak current of CGA were investigated. Under the optimised conditions, the linear range of ZIF-67/PEDOT/CP for the determination of CGA was 0.1 ∼ 40 μM, and the limit of detection (LOD) was as low as 0.003 μM (S/N = 3). Furthermore, the sensor was successfully used for the quantitative analysis of CGA in real samples.