Nanoporous graphene oxide/molybdenum disulfide based on quartz crystal microbalance gas sensor for total volatile basic nitrogen detection in salmon meat

Total volatile basic nitrogen (TVB-N) is a significant indicator for meat freshness evaluation. In this study, a simple hydrothermal method was utilized to synthesize the nanoporous graphene oxide/ molybdenum disulfide (NGO/MoS2) nanocomposites. The optimum detection effect of the polymerization process was optimized by using different proportions of NGO in the solution, and the NGO/MoS2 based quartz crystal microbalance (QCM) gas sensor was used to detect TVB-N in salmon meat for assessing its freshness. The NGO/MoS2 composites with different mass ratios were synthesized by hydrothermal method, and were characterized by FT-IR, Raman, XPS, SEM and TEM. The results showed that NGO/MoS2 had both functional groups on graphene oxide (GO) surface, marginal sites and active sites of MoS2. The NGO/MoS2 based QCM gas sensor was highly sensitive to TVB-N gases such as trimethylamine, dimethylamine and ammonia. Compared with other gases, NGO/MoS2 sensor had higher selectivity to TVB-N gases. The high responses of NGO/MoS2 based sensor to TVB-N gases were attributed to the positive synergistic effect of the porous structure, surface functional groups and high specific surface area of NGO and MoS2. Finally, the sensor has been applied for predicting salmon meat freshness.