A Turn-On Fluorescent Probe for Detection of Sub-ppm Levels of a Sulfur Mustard Simulant with High Selectivity

Abstract

A new type of fluorescent probe capable of detecting a sulfur mustard (SM) simultant at a concentration of 1.2 μM in solution and 0.5 ppm in the gas phase has been developed. Owing to its molecular structure with a thiocarbonyl component and two piperidyl moieties integrated into the xanthene molecular skeleton, this probe underwent a highly selective nucleophilic reaction with the SM simultant and generated a thiopyronin derivative emitting intensive pink fluorescence. The distinct difference in electronic structure between the probe and thiopyronin derivative generated a marked shift of the absorption band from 445 to 567 nm, which enabled an optimal wavelength propitious for exciting the thiopyronin derivative but adverse to the probe. Such efficient separation of the excitation wavelength and tremendous increase in fluorescence quantum yield, from less than 0.002 to 0.53, upon conversion from the probe to the thiopyronin derivative, jointly led to a distinct contrast in the beaconing fluorescence signal (up to 850-fold) and therefore the unprecedented sensitivity for detecting SM species.

Highly Photostable and Luminescent Donor–Acceptor Molecules for Ultrasensitive Detection of Sulfur Mustard

“…To date, examples of fluorescent detection of trace SM vapor remain very limited. [ 24,39–43 ] Therefore, ultrasensitive detection of SM vapor by a reliable fluorescence sensor is critical. Quantitative evaluation of the detection sensitivity was performed at the Chemical Defense National Laboratory, where SM vapors at different concentrations were available.…”

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

“…During the development of the detection paper, we also studied the option of using new specific chromogenic/fluorogenic reagents, potentially sensitive to sulfur mustard. Based on the literature, we synthesized and verified the reagents based on rhodamine-thioamide [21], benzothiazole (RHBT) [22], and pyronine (DPXT) [24]. We used solutions of reagents in common organic solvents (methanol, ethanol, chloroform) for the impregnation of the cellulose carrier, and after drying, we exposed it to droplets of sulfur mustard (HD) and simulant (CEES).…”

“…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]. The issue is that most of these chemosensors have only been verified using simulants (e.g., diethyl chlorophosphate (DCP), 2-chloroethyl ethyl sulfide (CEES), etc.…”

Fluorescence detection of chemical warfare agents

“…图 5 荧光传感分子64与神经性毒剂模拟物的反应机理及 产生的荧光变化 [2] (网络版彩图) 图 6 (a) 传感分子71对梭曼的检测机理; (b) 传感分子73对 神经性毒剂模拟物DCP的检测机理 [2] (网络版彩图) Tian等 [16] 在以上基础上进一步优化了荧光分子结 构, 将气相样品的检测限降低到0.5 ppm (图10).…”