Detection of Euschistus heros and Diceraeus melacanthus volatile semiochemicals using PANI.Ag cantilever nanosensor

A silicon cantilever coated with PANI.Ag film was used as a sensor of synthetic solutions of volatile organic compounds (VOCs) produced by stink bugs and blends of VOCs released by males and females of Euschistus heros and Diceraeus melacanthus . The frequency shifts of the gas sensor due to the adsorption of the VOCs under investigation were measured. The male blend of E. heros was composed of defensive compounds and sex pheromones, whereas the male and female blends of D. melacanthus and female E. heros evaluated were composed of defensive compounds. The results showed a high interaction of the sensitive layer of the cantilever sensor with the methyl 2,6,10-trimethyltridecanoate compound. When the three defensive compounds, tridecane, (E)-4-oxo-2-hexenal, and (E)-2-octenal, were measured as individual compounds, there was a very low response from the cantilever and no difference compared to the sensor response to air, and a similar response was observed with blends from D. melacanthus males and females and E. heros females. The resonance frequency of the cantilever showed a difference only when the compound methyl 2,6,10-trimethyltridecanoate was present. Furthermore, this response appears to be related to the chemical structure of the compounds, and there is no relationship with the amount of compounds because the sex pheromone components were significantly lower in the blend than the defensive compounds. Thus, the PANI.Ag gas sensor present potential to be used as a device module capable of monitoring volatile compounds for agricultural applications.