Sub-ppb detection of methyl jasmonate and methyl salicylate using surface plasmon resonance sensor with graphene oxide-Al films and violet light

Abstract We achieved sub-ppb detection of plant hormone derivatives, methyl jasmonate (MeJA) and methyl salicylate (MeSA), using a surface plasmon resonance sensor with an aluminum (Al) sensor chip decorated with graphene oxide (GO), and violet light. GO-decorated Al sensor chip on quartz glass substrates enabled detection of 0.7 ppbv MeJA and 0.28 ppbv MeSA. GO decoration doubled MeJA signals compared to a SiO2-covered chip and slightly increased MeSA signals. Distinct adsorption behaviors of MeJA and MeSA on GO and SiO2 were analyzed, demonstrating the potential of the sensor for rapid, non-destructive plant health monitoring in agriculture.