Molybdenum
oxide nanomaterials have recently attracted widespread
attention for their unique optical properties and catalytic performance.
However, until now, there is little literature on the application
of photoluminescent molybdenum oxide nanomaterials in biological and
pharmaceutical sensing. Herein, photoluminescent molybdenum oxide
quantum dots (MoO
x
QDs) were synthesized
via a facile method, and then, the synthesized MoO
x
QDs were further applied as a new type of photoluminescent
probe to design a new off–on sensor for captopril (Cap) determination
on the basis of the fact that the quenched photoluminescence of MoO
x
QDs by Cu
2+
was restored with Cap
through specific interaction between the thiol group of Cap and Cu
2+
. Under optimal conditions, the restored photoluminescence
intensity showed a good linear relationship with the content of Cap,
ranging from 1.0 to 150.0 μM, with a limit of detection of 0.51
μM (3σ/k). Additionally, the content of Cap in pharmaceutical
samples was successfully detected with the newly developed off–on
sensor, and the recoveries were 99.4–101.7%, which suggest
that the present off–on sensor has a high accuracy.