Accelerated Life Tests for Time-Dependent Response Characterization of Functionalized Piezoelectric Microcantilever-Based Gas Sensors

This article explores the accelerated lifetime test approach to characterize the time-dependent response of a piezoelectrically driven microcantilever (PD-MC) based gas sensor. The novelty here relies on demonstrating how accelerated lifetime tests can be useful to differentiate sensing mechanisms for non-linear gas sensors. The results show the determination of the sensor’s optimum operation time while maintaining result validity. The approach is demonstrated for 1,5-diaminopentane (cadaverine), a volatile organic compound (VOC) whose concentration in meat and fish products has been proven viable for determining the shelf life. A PD-MC functionalized with a cadaverine-specific binder was therefore incorporated into a hand-held electronic nose, and the response was found to be highly reliable within a specific resonance frequency shift, enabling the accurate prediction of meat and fish expiration dates. To identify the limits of detection in terms of cadaverine concentration and sensor lifetime, this study applies the results of accelerated life tests into a Weibull distribution analysis to extract the expected time to failure. For the accelerated life tests, a functionalized PD-MC was exposed to high concentrations of cadaverine, i.e., 252.3 mg/kg, 335.82 mg/kg, and 421.08 mg/kg, compared to the nominal concentration of 33 mg/kg observed in meat and fish samples. Furthermore, we demonstrate the differentiation of the response mechanisms of the system accruing from the concentration-dependent interaction of cadaverine with the binder. This enables the determination of the upper limit of the analyte concentration for a stable response. The findings suggest that the functionalized PD-MC sensor exhibits a linear and predictable response when exposed to a standard cadaverine concentration of 33 mg/kg for up to 93.01 min.