Ppb-level detection of trimethylamine as biomarker in exhaled gas based on MoO3/V2O5 hierarchical heterostructure

The toxic gas trimethylamine (TMA) with fishy odor can not only be used as an indicator for evaluating seafood spoilage, but also as a biomarker for trimethylaminuria and kidney disease. This paper constructs a ppb-level trimethylamine gas sensor that operates at room temperature based on MoO3/V2O5 nanocomposites, which were fabricated by hydrothermal synthesis process. The adsorption energy of TMA on sensitive materials was calculated through the density functional theory, and the sensing mechanism was explored by simulating the adsorption process of TMA on the sensitive materials. The response (11.37%) of MoO3/V2O5 composites to ultra-low concentration (20 ppb) TMA was better than that of pure MoO3 nanorods (5.49%) and V2O5 nanospheres (6.36%) at room temperature. Compared with pure MoO3 sensors, an n-n heterojunction is formed between MoO3 and V2O5, which enhances the sensing performance of pure sensing material for TMA. In addition, the detection of exhaled gas in simulated kidney disease patients indicates that this sensor has great potential as an effective TMA detection tool in the field of non-invasive disease diagnosis.