An oPD-CD doped zirconium-based metal–organic frame composite fluorescence probe for efficient and selective detection of nitric oxide

A novel composite fluorescence probe (oPD-CDs@UiO-66-NH2) was successfully prepared for NO detection in the aqueous phase, where carbon quantum dots (oPD-CDs) with NO recognition units were doped in a hydrothermally stable metal–organic framework material (UiO-66-NH2). oPD-CDs and UiO-66-NH2 combined by electrostatic adsorption, and oPD-CDs were uniformly distributed within the pore channel of UiO-66-NH2. This not only suppressed the aggregate induced fluorescence quenching occurring in carbon quantum dots, but also facilitated the efficient detection of NO. The prepared novel fluorescence probes were more sensitive to NO detection than pure oPD-CDs. NO can be detected in a wide linear concentration range of 6.25–500 μM with a lower limit of detection of 4.27 μM. The probes had high selectivity for NO analogs as well as other common substances. This was mainly attributed to the modification of UiO-66-NH2 by oPD-CDs, which can improve the efficient and selective adsorption of NO.