Wireless gas detection with a smartphone via rf communication

Abstract

Chemical sensing is of critical importance to human health, safety, and security, yet it is not broadly implemented because existing sensors often require trained personnel, expensive and bulky equipment, and have large power requirements. This study reports the development of a smartphone-based sensing strategy that employs chemiresponsive nanomaterials integrated into the circuitry of commercial near-field communication tags to achieve non-line-of-sight, portable, and inexpensive detection and discrimination of gas-phase chemicals (e.g., ammonia, hydrogen peroxide, cyclohexanone, and water) at part-per-thousand and part-per-million concentrations.RFID | NFC | sensor | nanomaterials | wireless P ortable chemical sensors are needed to manage and protect the environment (1), human health (2, 3), and quality of life (4). Examples include sensors for point-of-care diagnosis of disease (5), detection of explosives and chemical warfare agents (6), indication of food ripening and spoilage (7), and monitoring of environmental pollution (1). Connecting sensors with information technology through wireless rf communication is a promising approach to enable cost-effective onsite chemical detection and analysis (8). Although rf technology has been recently applied toward wireless chemical sensing, current approaches have several limitations, including lack of specificity to selected chemical analytes, requirements for expensive, bulky, fragile, and operationally complex impedance and network analyzers, and reliance on extensive data processing and analysis (8-13). We report herein the adaptation of a nascent technology embedded in modern smartphones-near-field communication (NFC)-for wireless electronic, portable, non-line-of-sight selective detection of gasphase chemicals ( Fig. 1 and Fig. S1). We demonstrate this concept by (i) incorporating carbon-based chemiresponsive materials into the electronic circuitry of commercial NFC tags by mechanical drawing and (ii) using an NFC-enabled smartphone to relay information regarding the chemical environment (e.g., presence or absence of a chemical) surrounding the NFC tag. This paper illustrates the ability to detect and differentiate partper-million (ppm) concentrations of ammonia, cyclohexanone, and hydrogen peroxide. We demonstrate the ability to couple wireless acquisition and transduction of chemical information with existing smartphone functions [e.g., Global Positioning System (GPS)] (Movie S1).Many commercial smartphones and mobile devices are equipped with NFC hardware configured to communicate wirelessly with NFC "tags"-simple electrical resonant circuits comprising inductive (L), capacitive (C), and resistive (R) elements on a plastic substrate (Fig. 1). The smartphone, such as the Samsung Galaxy S4 (SGS4) used in this study, communicates with the battery-free tag by powering its integrated circuit (IC) via inductive coupling at 13.56 MHz (14). Power transferred from the smartphone to the IC is, among other variables, a function of the transmission frequency (f), the re...

Single strip solid contact ion selective electrodes on a pencil-drawn electrode substrate

“…Recently, mechanical abrasion of compressed either single or multi-walled CNTs directly onto the surface of the paper was suggested as an alternative approach to develop chemiresistive sensors for gas detection. [31][32][33][34][35] These sensing devices exhibited sufficient conductivity (10-30 kΩ) and showed similar/improved sensing characteristics to their counterparts prepared using solventdispersion techniques. More recently, pencil drawn electrodes (PDEs) prepared via mechanical abrasion of graphite on solid substrate have been developed and used as voltammetric sensors for the detection of metal ions.…”

“…The growth of fields like Big Data heavily relies on the ability to collect large amounts of data, and it has been argued that the next big leap in communication will happen by integrating chemical sensors with mobile communication devices. 35,51,52 Clearly, to enable such advances in chemistry, it would be important to involve members of public in collection of chemical data. This could be achieved with sensors that are so simple and cheap that citizens can prepare and use them at home using simple household items.…”

Single-Walled Carbon Nanotube–Metalloporphyrin Chemiresistive Gas Sensor Arrays for Volatile Organic Compounds

“…Swelling mechanisms have been posited previously for both polymer-and CNT-based sensors. 2,3,23,24,26,27 We used Raman spectroscopy to examine the changes in the sensing material caused by analytes and found that while relative effects observed in this experiment did not clearly correlate with the magnitude of different responses, both ionic and neutral porphyrin-SWCNT composites exhibited changes in the relative intensities of the radial breathing mode (RBM) absorptions upon exposure to analytes, suggesting that analyte vapors induced changes in CNT-CNT interactions (see Supporting Information figures S9 and S10). 28,29 We observe inverted behavior for the ionic metalloporphyrin composite upon exposure to analyte as compared to the neutral case, a relative increase in the peak at 265 cm -1 rather than a decrease.…”

Single‐Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage

“…The strong responses are dosimetric and could find utility in single-use wireless tags. [19] Detection of BAs in meat samples requires a strategy for distinguishing them from the complex matrix. To assess their selectivity toward amines, we measured responses of [Co(tpp)]ClO4-SWCNT devices to volatile compounds representing a wide range of functional groups ( Figure 5).…”