Portal de Periódicos da CAPES

Carbon dots and fluorescein: The ideal FRET pair for the fabrication of a precise and fully reversible ammonia sensor

2017; Elsevier BV; Volume: 253; Linguagem: Inglês

10.1016/j.snb.2017.07.001

1873-3077

Chiao-Peng Hsu, Zahralsaadat Hejazi, Emre Armagan, Shanyu Zhao, Michel Schmid, Haijiang Zhang, Hang Guo, Lukas Weidenbacher, René M. Rossi, Matthias M. Koebel, Luciano F. Boesel, Claudio Toncelli,

Luminescence and Fluorescent Materials

Abstract Monitoring of ammonia in the gas phase, a ubiquitous bulk chemical, is of paramount importance to ensure the safety of industrial workers. The present paper describes a solid-state optical ammonia sensor based on Forster resonance energy transfer (FRET) between narrowly dispersed blue-emitting carbon nanodots (CNDs) as FRET donor and fluorescein as FRET acceptor. The fluorophores were physically entrapped in a close to superhydrophobic sol–gel matrix, in turn deposited on a PVDF-HFP electrospun fiber membrane. The CNDs were synthesized via pyrolysis of ethylenediaminetetracetic acid (EDTA) in the presence of a hydrogen peroxide solution. X-ray photoelectron spectroscopy (XPS) confirmed a high surface coverage of hydrophilic groups, which is a result the addition of hydrogen peroxide in the reaction mixture. This translates into higher electrostatic interactions between ammonia and the fluorophores, in turn related to reduced FRET inter-distance between fluorescein and CNDs. If calibrated with respect to the fluorescein signal, the sensor shows a linear calibration with a remarkably low limit of detection, i.e. 110 ppb, and adequate reproducibility up to six N2/NH3 cycles.