Ultra-Sensitive Gaseous Styrene and Isoprene Detection with a Ratiometric Fluorescence Probe of Eu(III)-Incorporated UiO-67

The development of probes for the efficient detection of volatile organic compounds is crucial for both human health protection and environmental monitoring. In this study, we successfully synthesized a ratiometric fluorescent sensing material [Eu-UiO-67 (1:1)], featuring dual-emission fluorescence peaks via a one-pot method. This material demonstrated exceptional ratiometric fluorescence recognition properties for liquid styrene and isoprene, achieving low limit of detections (LODs) of 6.2 and 20.24 ppb, respectively. Furthermore, we leveraged its outstanding photoluminescence properties to fabricate a Eu-UiO-67 film, which exhibited distinctive fluorescence responses toward gaseous styrene and isoprene. This unique behavior resulted in LODs of 12.42 ppb for gaseous styrene and 15.39 ppb for gaseous isoprene. The investigation into the sensing mechanisms revealed that the fluorescence response for styrene was mediated by an internal filtration effect, which arose from the competitive energy absorption between styrene and the Eu-UiO-67 (1:1) material. In contrast, fluorescence resonance energy transfer occurred between isoprene and the Eu-UiO-67 (1:1) materials. This approach offers a sensitive and reliable method for the detection of liquid/gaseous styrene and isoprene.