Bi-MOF-based point-of-care testing paper for dual-mode detection of HS.

Hydrogen sulfide (HS) is noxious gas and significantly threatens human health. Herein, a Bi-based metal-organic frameworks (Bi-MOFs) based paper analysis device (PAD) has been developed for rapid and effective dual-mode detection of HS. The dominant HS sensing mechanism is explored. The HS can react with Bi-MOF to form bismuth sulfide (BiS) MOF (BiS-MOF), changing the color of PAD from white to black. The distinguish color change makes it very convenience for visible detection. Meanwhile, the generated BiS-MOF exhibits excellent photothermal property, endowing it possible for photothermal imaging detection. In this regard, the PAD boasts a wide linear detection range of 0-40 μM for HS with an impressively low limit of detection (LOD) (0.23 μM). The constructed sensing system is demonstrated with outstanding selectivity and storage stability. Satisfied recovery is reached for HS detection in diverse real samples. Interestingly, the PAD can be used as intelligent label for assessing meat freshness by monitor HS release from meat under different storage temperatures. With integration capabilities of smartphones, the portable and user-friendly PAD offers a simple and rapid solution for on-the-go detection of HS in food and environment. The investigation provides an instructive way for environment monitoring and food safety guarding.