Simple and Efficient Chromophoric-Fluorogenic Probes for Diethylchlorophosphate Vapor

Abstract

In this work, we developed two small-molecule probes for real-time and onsite detecting of diethylchlorophosphate (DCP) vapor by incorporating amine groups into Schiff base skeletons. Both probes can be easily synthesized with high yield through one-step and low-cost synthesis. They can detect DCP vapor in the chromophoric-fluorogenic dual mode, which combines both the advantages of the visualization of color sensing and the high sensitivity of the fluorescence sensing. Furthermore, its sensing is based on the "turn-on" mode which can avoid the interference arising from photobleaching or fluorescence quenching agents based on "turn-off" mode. The detection limit was quantified to be as low as 0.14 ppb.

Rational Construction of Highly Tunable Organic Charge-Transfer Complexes for Chemiresistive Sensor Applications

“…Based on literature reports, the N-containing group presented an intense nucleophilic attack capacity toward the phosphonyl group of DCP, and then an ionic salt system will be formed after the reaction with DCP. 8,26,37 Hence, the conductivity of the ionic salt system will be much higher than that of the neutral CT complex, which agrees well with our test results in that all of the sensing films showed a resistance decrease after the DCP sensing process. Figure S5 presented the XRD patterns of the complexes before and after DCP sensing.…”

“…In reality, diethyl chlorophosphate (DCP) serves as a mimic for sarin due to its similar activity but low toxity. 26,27 At this time, there are many methods for detecting DCP vapor, and the detection limit is in the ppb range. However, most of these methods are complicated in operation and costly, limiting their applications.…”

Challenges in Fluorescence Detection of Chemical Warfare Agent Vapors Using Solid‐State Films

“…Materials with nitrogen‐based nucleophiles constitute an important class of fluorescent sensors investigated for the detection of nerve agent and simulant vapors. N‐based chemosensors ( Figure ) include quinoline (e.g., 2 ), pyridine (e.g., 3 and 4 ), Schiff bases (e.g., 5 ), amines (e.g., 6 ), or quinoxaline . Solid‐state detection of the nerve agents has been reported to be achievable in different formats including drop‐casting ( 2 ) in a poly(ethylene oxide) (PEO) matrix, having ( 6 ) and ( 4 ) sorbed onto microbeads or glass, or filter paper, respectively, or in the form of a neat thin film by spin‐coating ( 3 ) or ( 5 ) onto quartz substrates.…”

“…Two typical detection mechanisms have been used with these materials to detect the nerve agents: protonation to enhance intramolecular charge transfer (ICT), e.g., compounds 2 – 5 and illustrated with 2→2′ , and phosphorylation to inhibit the photoinduced electron transfer (PET) process ( 6 →6′ ). Both the mechanisms lead to a fluorescence “turn on” response . There are other N‐based sensing materials (not listed here) that give fluorescence “turn off” signals, but the sensing mechanisms are unclear .…”

Detection Papers with Chromogenic Chemosensors for Direct Visual Detection and Distinction of Liquid Chemical Warfare Agents

“…Chemical reactions are more selective, but the selection of chromogenic agents, suitable for practical applications, was very limited in the past. However, during the last two decades, a lot of original works were published, referring particularly to chromogenic chemosensors for the G type nerve agents, featuring a significant change of color as well as good selectivity and sensitivity; these chemosensors are based on hydroxyl-activation, N-activation, and contain metal ions (coordination compounds), or possibly form reactive polymers [7][8][9][10][11][12][13][14][15][16][17][18][19]. Many publications deal with new chemosensors for sulphur mustard [20][21][22][23][24].…”