The conductometric sensor based on 25,27-di-(5-thio-octyloxy)calix[4]arene-crown-6 was developed for the quantitative analysis of ammonium. The calixarene was immobilized on the surface of the planar interdigitated electrodes by attachment of its dialkyl sulfide groups to the surface of the gold electrodes. The intrinsic ability of the calixarene to capture ammonium was studied in the conductometric measuring mode and by the electrochemical impedance spectroscopy. The developed sensor showed high selectivity to ammonium in the presence of mono-, di-, and trivalent cations. Selective and highly sensitive detection of ammonium resulted from the complexation between the ammonium ions and a crown-ether fragment of the upper rim of the 25,27-di-(5-thio-octyloxy)calix[4]arene-crown-6 macrocycle. The developed sensor had high signal repeatability. Its sensitivity was found to be satisfactory for the forthcoming sensor application in the water-sample analysis; the linear range was 0.01-1.5 mM and limit of detection 10 μM.
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http://dx.doi.org/10.1186/s11671-016-1317-9 | DOI Listing |
Sensors (Basel)
December 2024
CNR-IPCF, Institute for Chemical-Physical Processes Messina, 98158 Messina, Italy.
Zinc oxide nanoparticles (ZnO NPs) with varying levels of nitrogen (N) doping were synthesized using a straightforward sol-gel approach. The morphology and microstructure of the N-doped ZnO NPs were examined through techniques such as SEM, XRD, photoluminescence, and Raman spectroscopy. The characterization revealed visible changes in the morphology and microstructure resulting from the incorporation of nitrogen into the ZnO lattice.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Luxembourg Institute of Science and Technology (LIST), 28 Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
Conjugated polymers have revolutionized the field of conductometric gas sensors for sensing toxic gases arising from the fast urbanization and industrialization. In this work, we report the synthesis of a series of 5,15-diaryl Ni(II) porphyrin-conjugated polymers () and their integration as the top layer on an octafluorinated copper phthalocyanine () sublayer to construct bilayer heterojunction (BLH) devices for ammonia sensing. For the first time, we report the pioneering demonstration of polarity engineering within a BLH device by manipulating the -substituent of the 5,15-diaryl Ni(II) porphyrin-conjugated polymer constituting the top layer of the BLH device.
View Article and Find Full Text PDFSensors (Basel)
October 2024
SENSOR Laboratory, University of Brescia, Via D. Valotti 9, 25133 Brescia, Italy.
We are proposing a novel self-assembled monolayer (SAM) functionalized ZnO nanowires (NWs)-based conductometric sensor for the selective detection of hydrogen (H). The modulation of the surface electron density of ZnO NWs due to the presence of negatively charged terminal amine groups (-NH) of monolayers leads to an enhanced electron donation from H to ZnO NWs. This, in turn, increases the relative change in the conductance (response) of functionalized ZnO NWs as compared to bare ones.
View Article and Find Full Text PDFSensors (Basel)
October 2024
Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
Pure tin oxide (SnO) as a typical conductometric hydrogen sulfide (HS) gas-sensing material always suffers from limited sensitivity, elevated operation temperature, and poor selectivity. To overcome these hindrances, in this work, hollow CuO-SnO nanotubes were successfully electrospun for room-temperature (25 °C) trace HS detection under blue light activation. Among all SnO-based candidates, a pure SnO sensor showed no signal, even toward 10 ppm, while the 1% CuO-SnO sensor achieved a limit of detection (LoD) value of 2.
View Article and Find Full Text PDFAnal Chem
September 2024
School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wang Chan Valley, Rayong 21210, Thailand.
We describe a conductometric assay of the enzymatic conversion of glucose to gluconic acid by dissolved glucose oxidase (GOx), using the generation of proton and gluconate from the reaction product dissociation for glucose detection. Simple basics of ionic conductivity, a silver/silver chloride wire pair, and a small applied potential translate glucose-dependent GOx activity into a scalable cell current. Enzyme immobilization and complex sensor design, involving extra nanomaterials or microfabrication of electrode structures, are entirely avoided, in contrast to all modern electrochemical glucose biosensors.
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