Multigas Differentiation With Individual Electrochemical Gas Sensors

Existing gas sensors are low cost and operate at low power. However, their high gas cross-sensitivity reduces their acceptance for reliable monitoring of ambient environmental pollutants, indoor air quality, breath biomarkers, and many other applications. Thus, at present, traditional analytical instruments are used for accurate gas detection and multi-gas differentiation. These popular instruments unfortunately require periodic maintenance and demand a lot of electrical power even in their fieldable formats. A competing technology is individual multi-response (a.k.a. multivariable) sensors to meet contemporary gas monitoring needs. In this Letter, we present results on two methodologies to achieve multi-gas differentiation with individual amperometric electrochemical sensors. In one methodology, a sensor was operated at two modulated bias levels. In the second methodology, a sensor was operated with impedance and direct current readouts at one or two bias levels. For multi-gas differentiation, a standard unsupervised multivariate data analysis was sufficient. This direction in multi-gas detection with individual multi-response (multivariable) sensors will compete with traditional instruments and will improve the “3S” sensor system characteristics—sensitivity, selectivity, and stability, facilitating green analytical chemistry implementations and leading to positive societal impact.