A terbium(iii)-based coordination polymer for time-resolved determination of hydrogen sulfide in human serum via displacement of copper(ii)

Abstract

Lanthanide coordination polymers (LCPs) have attracted great interest because of their special photophysical properties, diverse compositions and architecture. Here, we describe the design and synthesis of LCP containing guanosine monophosphate (GMP), oxalate (OX) and terbium ions (Tb³⁺), which works as a fluorescent probe for the determination of hydrogen sulfide (H₂S). The fluorescence of the LCP was quenched by Cu²⁺ which bound to the system to form a complex of GMP/Tb/OX–Cu. On addition of sulfide, Cu²⁺ was displaced from the GMP/Tb/OX–Cu CP due to formation of CuS. This resulted in a strong increase in fluorescence which was measured in the time-resolved mode. Among the various anions studied, only sulfide showed this effect. As a probe for the detection of H₂S, GMP/Tb/OX–Cu CP showed a good linear response for H₂S in the range from 1 to 60 μM with a detection limit of 0.5 μM. GMP/Tb/OX–Cu CP as a fluorescent probe displayed excellent selectivity to H₂S. Furthermore, GMP/Tb/OX–Cu CP was successfully applied to measure the level of H₂S in human serum samples and satisfactory results were obtained. We believe that the presented strategy might create new avenues for the design and application of fluorescent probes based on LCPs.