Detecting Chemical Hazards with Temperature-Programmed Microsensors: Overcoming Complex Analytical Problems with Multidimensional Databases

Abstract

Complex analytical problems, such as detecting trace quantities of hazardous chemicals in challenging environments, require solutions that most effectively extract relevant information about a sample's composition. This review presents a chemiresistive microarray-based approach to identifying targets that combines temperature-programmed elements capable of rapidly generating analytically rich data sets with statistical pattern recognition algorithms for extracting multivariate chemical fingerprints. We describe the chemical-microsensor platform and discuss its ability to generate orthogonal data through materials selection and temperature programming. Visual inspection of data sets reveals device selectivity, but statistical analyses are required to perform more complex identification tasks. Finally, we discuss recent advances in both devices and algorithms necessary to deal with practical issues involved in long-term deployment. These issues include identification and correction of signal drift, challenges surrounding real-time unsupervised operation, repeatable device manufacturability, and hierarchical classification schemes designed to deduce the chemical composition of untrained analyte species.

Temperature Sculpting in Yoctoliter Volumes

“…1 ms) 67,68,82 , the novel method can clearly probe reversible equilibrium processes between different species and molecules that can fully or partially enter the pore (Figure 4), which could provide additional control of nanopore-based DNA sequencing-by-synthesis methods 103 . It also has the potential to study the kinetics of structural changes that occur in synthetic and biological polymers by the use of complex temporal temperature profiles (Figure 5) and to identify or discriminate between different molecules in solution, as has been demonstrated for the identification of gaseous species using micro-hotplates 104-106 . For example, applying a complex temperature time series (i.e.…”

Materials and Transducers Toward Selective Wireless Gas Sensing

“…119,120 Multiparameter gas sensing was also demonstrated using FETs 121,122 and temperature-programmed sensors. 123 …”

Sensor Array Design for Complex Sensing Tasks

“…They also open the potential to build sensor systems that can adapt to changing environments and sensing tasks, gaining efficiency by limiting the number of measurements made to only those that are necessary (66). For example, microhotplate sensors precisely control the temperature of a metal oxide sensor surface, thus altering the sensor response characteristics in a repeatable, programmable fashion (67,68). This approach has been demonstrated to provide enhanced information for complex sensing tasks such as detection of chemical vapors in backgrounds of common commercial cleaning products.…”

“…Numerous books and reviews of sensor array technology have since been authored with at least one published nearly every year since 1997, demonstrating the continued interest in and vitality of the approach (6,18,19,41,67,75,76,. The majority of these reviews are focused on describing various sensor technologies and applications for which sensor arrays have been used, whereas a smaller fraction focus instead on data analysis strategies for sensor arrays.…”