Direct Distinguishing of Methanol over Ethanol with a Nanofilm‐Based Fluorescent Sensor

Abstract

Methanol is extremely toxic to humans if ingested or if vapors are inhaled. Facile and reliable detection of methanol is an efficient way to reduce the risk of methanol poisoning. A great challenge in methanol detection lies in distinguishing methanol under high ethanol background. In this work, a nanofilm‐based fluorescent sensor for direct distinguishing methanol from pure ethanol or liquor is presented, where no sample pretreatment or sensor array is needed. The flexible, uniform, and amorphous nanofilm is synthesized via dynamic covalent binding‐driven self‐assembly of BTN and CB‐CHO at air/DMSO interface. The nanofilm shows a large Stokes shift (≈175 nm) and excellent photostability. Different from sensing films based on drip‐permeance or drop cast of organic fluorophores, sensing performance of the nanofilm shows little dependence on substrate. With the film, an optical sensor for methanol vapor detection is built and it can distinguish methanol not only from the mixture of methanol and ethanol (with ethanol content up to 90%), but also from the liquor (45% vol). The sensor shows excellent reusability and high selectivity over many commonly used organic solvent vapors. Moreover, the sensor can be used to discriminate industrial alcohol from medical alcohol and detect methanol gas leak.

A Fluorescent Alcohol Biosensor Using a Simple microPAD Based Detection Scheme

“…For example, silica-coated cellulose strips with a fluorescent chemical probe grafted to them can detect EtOH in gasoline with a 0.5 v/v% limit of detection (Gotor et al 2019). A carborane derivative film showed turn-on fluorescence whose strength and recovery rate was different for ethanol and methanol (MeOH), showing that the relative fraction of these two alcohols could be distinguished to about 1% (Han et al, 2021). Another sensor film with similar turn-on behavior also was shown in Ref.…”

Fluorescent Probes for Detection of Environmental Contaminants (NACs & VOCs): Probe Design from a Supramolecular Perspective

“…Recently in a new approach, Chakravarty et al . developed a small, electron‐rich, and twisted phenothiazine‐linked anthracene‐derived solid‐state emitter ( Probe 21 ) to recognize VOCs and organic solvents [81] . The authors reported the probe as a solvatochromic fluorophore and durable vapochromic compound, mainly in the solid‐state (Figure 17a–c).…”

Fluorometric Detection of Methanol by Using Triphenylamine Fluorophore Tethered Terpyridine Probe

“…Bazgir and co‐workers investigated imidazoisoindol‐5‐imine scaffold based fluorescent probes for methanol detection based on solvatochromism principle [15] . Miao and Fang research groups designed fluorescent nanofilm based sensor for methanol detection [16] . Effective discrimination of methanol, ethanol and propanol is reported using excited‐state intramolecular proton transfer (ESIPT) fluorophore [17] .…”

“…[15] Miao and Fang research groups designed fluorescent nanofilm based sensor for methanol detection. [16] Effective discrimination of methanol, ethanol and propanol is reported using excited-state intramolecular proton transfer (ESIPT) fluorophore. [17] Introduction of electron donor-acceptor (DÀ A) units on AIE fluorophore systems experience the fine-tuning the energy levels of their ground and excited states as well as modify the intramolecular charge transfer (ICT) process, resulting noteworthy wavelength-shifting in emission/absorption spectra.…”