Molecularly Imprinted Polymer‐Based Electrochemical Sensor for In Situ Detection of Free Proline in Cucumber Leaves

Abstract Proline is an important amino acid, which is crucial to plant growth and development. Accurate analysis of proline content is of great significance for understanding its physiological mechanism in plants. In this paper, according to the requirements for in‐situ detection in plants in precision agriculture, an electrochemical molecular imprinted polymers (MIP) sensor for determining proline in living plants was developed. Polypyrrole (PPy) was used as the functional monomer. To improve the performance of the MIP sensor, Au nanoparticles (NPs) were electrodeposited on the screen‐printed electrodes (SPEs) electrode. Thionine (Thi) was then electropolymerized on the SPEs to be used as an internal reference signal molecule. The MIP‐based proline sensor has the widest detection range of 1×10 −16 −0.01 M. And its detection limit is the lowest (9.18 aM) so far. It was also used for measuring free proline in the leaves of living cucumber seedlings under salt stress. The MIP‐based proline sensor has an important prospect for detecting the physiological status of plants in situ and will play an important role in smart agriculture.