Bulk acoustic wave resonator virtual sensor arrays for DMMP detection

Accurate detection of dimethyl methylphosphonate (DMMP), a simulant for chemical warfare agents, is vital for both public safety and military defense. However, conventional detection methods suffer from low selectivity, owing to interference from structurally similar compounds. In this study, we present a highly sensitive and selective gas sensor utilizing a solid-mounted film bulk acoustic resonator based on carbon nanotubes functionalized with hexafluoroisopropanol (HFiP) to enhance DMMP detection. This approach leverages the strong hydrogen bonding between HFiP and DMMP molecules to significantly improve the sensor’s adsorption capacity and selectivity. To further refine selectivity and at the same time solve the cross-sensitivity problem of sensitive membranes, we introduce a virtual sensor array design, generated by modulating the input power to the resonator, which enables the sensor to operate in multiple response modes across varying vibrational amplitudes. These multimodal responses are subjected to linear discriminant analysis, allowing precise differentiation of DMMP from other volatile organic compounds such as tributyl phosphate and dimethyl phthalate. Our results demonstrate superior performance in terms of both sensitivity and selectivity, offering a robust solution for detecting low-concentration DMMP in complex environments.