▎ 摘　　要

Thedetection of nitric oxide in human exhaled breath (EB) hasreceived wide attention due to its close relationship with respiratorytract inflammation. Herein, a ppb-level NO (x) chemiresistive sensor was prepared by assembling graphene oxide(GO) with a conductive pi-d conjugated metal-organicframework Co-3(HITP)(2) (HITP = 2,3,6,7,10,11-hexaiminotriphenylene)in the presence of poly(dimethyldiallylammonium chloride) (PDDA).The construction of a gas sensor chip was achieved by drop-castingthe GO/PDDA/Co-3(HITP)(2) composite onto ITO-PETinterdigital electrodes, followed by in situ reduction of GO to reducedgraphene oxide (rGO) in hydrazine hydrate vapor. Compared with barerGO, the nanocomposite shows significantly improved sensitivity andselectivity for NO (x) among various gasanalytes owing to its folded and porous structure as well as its numerousactive sites. The limit of detection (LOD) for NO and NO2 can reach as low as 11.2 and 6.8 ppb, respectively, and the response/recoverytime to 200 ppb NO is 24/41 s. These results indicate that rGO/PDDA/Co-3(HITP)(2) can achieve a sensitive and fast responsetoward NO (x) at room temperature (RT). Additionally,good repeatability and long-term stability were observed. Furthermore,the sensor shows improved humidity tolerance owing to the presenceof hydrophobic benzene rings in Co-3(HITP)(2).To demonstrate its ability in EB detection, EB samples collected fromhealthy individuals were spiked with a certain amount of NO to simulatethe EB of respiratory inflammatory patients. The sensor can successfullydistinguish healthy people from the simulated patients. Furthermore,in real clinical sample detection, the sensor can further differentiateacute respiratory inflammatory patients from the chronic ones.