Flexible sensor based on composites of hafnium diselenide, carboxylated single walled carbon nanotubes, and carboxylated graphene for in situ rutin detection in plants

Rutin, a natural flavonoid with anti-inflammatory and antioxidant properties, is widely found in plants and foods. To meet the demand for in situ detection of Ru in soft plant tissues, in this paper, a thin laser-induced graphene (LIG) electrode was prepared on polyimide (PI) and transferred to Ecoflex substrate, obtaining LIG/Ecoflex electrodes with good flexibility and tensile resistance. To further improve the electrochemical catalytic performance, nanocomposites of hafnium diselenide (HfSe 2 ), carboxylated single-walled carbon nanotubes (COOH-SWCNT), carboxylated graphene (COOH-GR) and nafion were also modified on the surface of LIG by a one-step dropping method. The HfSe 2 -COOH-SWCNT-COOH-GR-nafion/LIG/Ecoflex sensor could detect Ru in the range of 1 μM–700 μM under different pH values (4.5–7.4). It was also successfully used to in situ detection of Ru content in tomato leaves under different salt stress. The as-prepared sensor has important practical application prospects in the monitoring of plant physiological information in situ.