Emission Based Sensing of Subnanomolar Dissolved Carbon Dioxide Exploiting Electrospun Nanofibers

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

“…The development of electrospun nanofiber-based optical CO 2 sensors was first reported by Ertekin et al [ 48 , 49 , 50 ]. They used polymethylmethacrylate (PMMA) and ethyl cellulose (EC) as polymeric materials and electrospinning to fabricate optical chemical sensing agents.…”

“…Fluorescent dye N ′-[( E )-(4-nitrophenyl)methylidene]pyridine-4-carbohydrazide was doped together with ionic liquid [EMIM][BF 4 ] in the presence of perfluoro acids for fluorescence detection of CO 2 . Further, they proposed a similar electrospun nanofiber-based CO 2 sensor based on the spectrophotometric signal change of fluorophore bromothymol blue (BTB) [ 50 ]. The effect of ionic liquids with different anionic and cationic parts, i.e.…”

“…For example, a task-specific ionic liquid with an amine (–NH 2 ) group on the cation can capture CO 2 and significantly enhance the solubility of CO 2 in that particular ionic liquid [ 43 ]. A wide range of ionic liquid-based sensors has been developed so far for the detection and quantification of CO 2 gas [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. These ionic liquid-based CO 2 sensors are either optical-based [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ] or electrochemical-based sensors [ 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , ...…”

“…Optical CO 2 sensors based on the changes in the absorbance or fluorescence response have been reported by researchers [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. Usually, these optical sensors contain a chemically-active sensing agent, which changes the UV-VIS absorbance or fluorescence emission intensity in response to CO 2 .…”

“…They revealed photophysical and photochemical properties of the 8-hydroxy-pyrene-1,3,6-trisulfonate (HPTS) in ionic liquids, as well as the performance of the sensor for dissolved and gaseous CO 2 . Further, Ertekin et al reported an optical CO 2 sensor with ionic liquid-doped electrospun nanofibers based on the changes in the fluorescence signal intensity of an ion pair form of HPTS [ 49 , 50 ]. Further, Wolfbeis et al performed semi-quantitative determination of CO 2 by dissolving the pH indicators bromothymol blue, thymol blue, and HPTS along with a reference fluorophore in the silicone-ionic liquid emulsions [ 51 ].…”