posted on 2024-01-17, 17:34authored byNazanin Mosleh, Liam Hardaker, Rex Bartolini, Xiangcheng Sun
Due
to vast application of palladium in academia and industry and
its toxicity, it is critical to develop user-friendly, portable, and
affordable methods for accurately detecting ultratrace Pd. In this
study, a highly sensitive and selective fluorescent probe (N-butyl-4-alloxy-1,8-naphthalimide, compound 2) was synthesized,
which demonstrated multiple signals [enhanced fluorescence (FL), ratiometric
FL, and colorimetric responses] upon interaction with palladium. The
compound 2 was designed by incorporating a naphthalimide-based fluorescent
dye as the fluorophore and an allyl ether group as a responsive unit.
Utilizing a Pd0-triggered cleavage reaction by a deallylation
reaction through the Tsuji–Trost reaction, compound 2 exhibited
rapid response, wide linearity, exceptional sensitivity with a limit
of detection as low as 2.2 pM, and high selectivity toward palladium
species. In addition, as a ratiometric and enhanced FL response, the
probe could be developed as a portable sensor via naked eye visualization
for semiquantitative and selective detection of palladium. Integrating
with an easily available smartphone (with a camera and a color-analysis
app), potential in situ quantitative detection was achieved at a low
cost. The probe shows multiple signals for palladium detection and
potential as a portable sensor, and this work provides valuable insights
into developing sensors with good sensitivity, selectivity, improved
reliability, and portability for detection of palladium and other
analytes of interest.