Laser-engraved ammonia sensor integrating a natural deep eutectic solvent

LUCAS M. DUARTE; GOMEZ, FEDERICO J. V.; LUCAS M. DUARTE; GOMEZ, FEDERICO J. V.; MAKENZIE REYNOLDS; M. FERNANDA SILVA; WENDELL K.T. COLTRO; MAKENZIE REYNOLDS; GARCIA, CARLOS D.; M. FERNANDA SILVA; WENDELL K.T. COLTRO; GARCIA, CARLOS D.

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 157

0026-265X

Ammonia is a naturally-occurring gas, present throughout the atmosphere at sub-ppb concentrations. As result ofvarious processes, significantly higher concentrations can be found in the areas surrounding industrial andagricultural operations. In such cases, the presence of NH3 in air is not only associated with a very pungent odorbut can also affect the environment, animals, plants, and humans. Aiming to provide a simple platform tomonitor NH3 in air, a paper-derived gas sensor, integrating a natural deep eutectic solvent (NADES) was developed.The herein described paper-derived ammonia gas sensor was fabricated using direct laser scribing, toform a carbon-based interdigitated array. Characterization and optimization (using chemometrics) were performedto develop a material with the lowest possible resistivity. A unique feature of the proposed sensor is thatit integrates a natural deep eutectic solvent formed with lactic acid:glucose:water (LGH). This NADES conveysselectivity toward ammonia (over methanol, ethanol, 1-propanol, and water) and greatly enhances the sensitivityof the sensor (over the plain carbon array). The resistance of the sensor was dependent on the NH3concentration in the 0.11?40.6% range and rendered an estimated limit of detection of 0.33%. Although thesensitivity of the sensor is lower than that of others based on metallic oxides, the herein described approachrepresents a low-cost, portable, and simple way to address the need of emerging markets such as the NH3-basedfuel industry or waste treatment where most of the current sensors would be saturated.