Copper (II)-mediated fluorescence of lanthanide coordination polymers doped with carbon dots for ratiometric detection of hydrogen sulfide

- A ratiometric sensor for H2S based on lanthanide coordination polymer doped with carbon dots was presented.
- The binding and remove of Cu2+ mediate the fluorescence of the ratiometric sensor.
- The ratiometric sensor showed excellent selectivity and high sensitivity to H2S.
- The ratiometric sensor possesses the feature of reversible sensing.

This work presented a ratiometric sensor for hydrogen sulfide (H2S) based on Cu2+-mediated fluorescence of lanthanide coordination polymers (LnCPs) doped with carbon dots (CDs). The ratiometric sensor (CDs@ZIF-8@GMP/Tb) is fabricated by the self-assembly of terbium ion (Tb3+) and guanosine monophosphate (GMP) on the surface of zeolitic imidazolate framework-8 loaded with CDs (CDs@ZIF-8). In this ratiometric sensor, GMP/Tb moiety was employed as response signal due to the ON-OFF-ON behaviors of Tb3+ fluorescence upon the sequential addition of Cu2+ and H2S, while CDs@ZIF-8 served as reference signal because of the good stability of CDs fluorescence in the presence of Cu2+ or/and H2S. The ratiometric sensor can sensitively detect H2S with a detection limit of 150 nM by fluorescent spectrum method and 3 μM by naked eyes. Owing to the ultrastrong binding ability of H2S and Cu2+, the ratiometric sensor not only exhibits high selectivity to H2S against other anions, thiols and biological species, which allows detection of H2S in serum sample with satisfied recovery, but also possesses the distinct feature of reversible sensing. We believe that the present study will provide a new insight into the design and application of LnCPs-based ratiometric fluorescent sensors.

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