Sahar Khaksar Haghani, Ali A. Ensafi, Nafiseh Kazemifard, Behzad Rezaei,

Abstract— In this work, an optical sensor based on zinc oxide quantum dots (ZnO-QDs) was used to determine the chlorogenic acid (CGA). First, ZnO-QDs were prepared using a sol-gel method. Next, a thin film of silica was formed on the surface of ZnO-QDs using a reverse microemulsion technique. To prepare the molecularly imprinted polymer (MIP), 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) were employed as a functional monomer and a cross-linker, respectively. Finally, the ZnO-QDs@MIP composite was used to measure CGA. Different variables, affecting the optical signal of the sensor, were optimized. Under the optimal conditions, the linear dynamic range of the optical sensor was from 0.2 to 5.3 μg mL–1 CGA with a detection limit as 0.06 μg mL–1. The effect of several potentially interfering species was investigated, and the results confirmed an excellent selectivity of the sensor for the measurement of CGA. Using this sensor to measure CGA in human plasma samples showed that the sensor is also capable of measuring CGA in complex matrix samples.

Index Terms— Optical sensor, Molecularly imprinted polymer, ZnO quantum dots, Chlorogenic acid.