Molybdenum trioxide embedded graphitic carbon nitride sheets modified electrode for caffeine sensing in green tea and coffee powder

The development of a screen-printed electrochemical sensor based on molybdenum trioxide (MoO 3 ) grown on the graphitic carbon nitride sheets (GCNS) nanocomposite was investigated for its ability to serve as an extremely sensitive and selective sensor towards caffeine (CAF). The MoO 3 @GCNS nanocomposite was synthesized through a simple hydrothermal method and was analyzed using spectroscopic and microscopic techniques (XPS, FT-IR, and FE-SEM). Voltammetry outcomes illustrated the enhancement of electrocatalytic oxidation of CAF at MoO 3 @GCNS modified electrode with higher oxidation current and also significantly reduced oxidation potential because of the synergetic effect between MoO 3 and GCNS as compared to pure MoO 3 and GCNS modified electrode. DPV results of MoO 3 @GCNS modified electrode displayed two wide straight lines (ranges of 0.5–359 μM and 410–810 μM) with a limit of detection of 21.24 nM with appreciable selectivity of 11.584 μA μM −1 cm −2 for CAF sensing. The modified electrode was further used for the detection of CAF in green tea and coffee powder samples. • New approach for electrochemical sensing of caffeine based MoO 3 grown on the GCNS modified SPCE. • The lowest LOD and sensitivity are calculated to be 21.24 nM and 11.584 μA μM −1 cm −2 for CAF sensing. • The proposed electrode was successfully applied for the detection of CAF in green tea and coffee powder samples.