achieved by bubbling a larger volume of contaminated air
into the assay solution.
In summary, a chromogenic and fluorogenic assay of a
nerve agent simulant was developed based on reactive organo-
phosphate triggered irreversible opening of the deoxylactam of
dRB-AE. The assay is sensitive and exhibited improved
kinetics relative to a prior sensor,5 allowing detection of
reactive organophosphates with the aid of instruments or
possibly with ‘‘naked eyes’’. We anticipate that rhodamine-
deoxylactams which are poised to analyte mediated opening of
the intramolecular deoxylactam will be useful as the universal
signal reporting platform for fluorogenic sensing of many
other chemically reactive species with appropriate structural
modifications.
Fig. 5 HRMS confirmation of formation of compound 2 in the
reaction of dRB-AE with diethyl chlorophosphate.
This work was supported by grants from NSF China
(20802060, 21072162), Natural Science Foundation of Fujian
Province of China (2011J06004) and the Fundamental
Research Funds for the Central Universities (2011121020).
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Rhodamine-hydroxamate has been reported to detect diethyl
chlorophosphate via Lossen rearrangement.5 Sensing of diethyl
chlorophosphate with dRB-AE was further evaluated using
rhodamine-hydroxamate as the control to compare their
efficiency. The dRB-AE based assay furnished highly fluorescent
and deep colored species that is suitable for visual detection.
Compared to the rhodamine-hydroxamate based assay where the
fluorescence emission intensity declined gradually in the late
phase, the dRB-AE based assay gave highly stable fluorescence
signals (Fig. 6), allowing accurate detection of nerve agents by
fluorometry. It is preferential to detect the ppb level of gaseous
nerve agents for practical applications. Here we show that dRB-
AE is able to detect a single aliquot of diethyl chlorophosphate
in DMF solution at the ppm range. We anticipate that the
detection of gaseous nerve agents with dRB-AE might be
5 S. Han, Z. Xue, Z. Wang and T. B. Wen, Chem. Commun., 2010, 46,
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c
11470 Chem. Commun., 2011, 47, 11468–11470
This journal is The Royal Society of Chemistry 2011