Smartphone-based electrochemical microsensor in combination with internet of things for remote monitoring of salicylic acid in plant.

Salicylic acid (SA) is an important plant hormone that not only regulates many physiological processes and immunity of plants, but also reflects the health status of plants. Therefore, developing a portable, in-situ and real-time, and remote SA monitoring system is very important to smart agricultural monitoring and early warning of plant health. Herein, we developed a detection system consists of a sensitive and portable electrochemical microsensors, miniature electrochemical devices, smartphones equipped with applications, and Internet of Things perform, which not only can obtain monitoring of the SA dynamic changes in tomato leaves in-situ and real-time, but also achieve remote monitoring and data sharing. The electrochemical microsensor based on the platinum electrode with 100 μm diameter, which was modified by conductive carbon cement and multi walled carbon nanotubes for detection SA, with a linear range of 0.5-8 μM and a limit of detection of 0.3724 μM. Smartphones were used to connect miniature electrochemical devices, power replenishment, command control, data analysis, result display, and remotely transmit the obtained data to the Internet of Things. Remote continuous in vivo monitoring of SA dynamic levels in tomato leaves under Pst DC3000 stress has been achieved. The results indicated that the combination of electrochemical microsensors based on smartphones and the Internet of Things can not only be used for remote monitoring of plants, but also for data sharing, greatly facilitating the analysis of detection results, which provides new ideas for future research on smart agricultural monitoring and early warning of plant health.