Mustard gas [sulfur mustard (SM)]
and phosgene are the
most frequently
used chemical warfare agents (CWAs), which pose a serious threat to
human health and national security, and their rapid and accurate detection
is essential to respond to terrorist attacks and industrial accidents.
Herein, we developed a fluorescent probe with o-hydroxythioketone
as two sensing sites, AQso, which can detect and distinguish mustard
gas and phosgene. The dual-sensing-site probe AQso reacts with mustard
gas to form a cyclic product with high sensitivity [limit of detection
(LOD) = 70 nM] and is highly selective to SM over phosgene, SM analogues,
active alkylhalides, acylhalides, and nerve agent mimics, in ethanol
solutions. When encountering phosgene, AQso rapidly converts to cyclic
carbonate, which is sensitive (LOD = 14 nM) and highly selective.
Their sensing mechanisms of AQso to mustard gas and phosgene were
well demonstrated by separation and characterization of the sensing
products. Furthermore, a facile test strip with the probe was prepared
to distinguish 2-chloroethyl ethyl sulfide (CEES) and phosgene in
the gas phase by different fluorescence colors and response rates.
Not using the complicated instrument, the qualitative and quantitative
detection of CEES or phosgene can be achieved only by measuring the
red–green–blue (RGB) channel intensity of the test strip
after being exposed to CEES or phosgene gas by the smartphone with
an RGB color application.