Highly sensitive trimethylamine QCM sensor based on porous functionalized tungsten disulfide/polyacrylic acid composite for seafood freshness detection

A quartz crystal microbalance (QCM) sensor based on tungsten disulfide (WS2) and polyacrylic acid (PAA) nanocomposite coating was introduced for trimethylamine (TMA) gas molecule detection. WS2 nanosheets were prepared by hydrothermal method and polyacrylic nanoparticles were prepared by solution polymerization. WS2, PAA and WS2/PAA sensors were prepared by spraying. The macrostate, microstructure and elementary composition of the nanomaterials were verified by characterization methods. The prepared WS2 is rich in functional groups such as hydroxyl, carboxyl and amino groups, which effectively enhances the synergy effect of multiple sensing materials and the interaction with target molecules. The sensor performance was tested at 25 °C and 33 % RH. Experimental results show that WS2/PAA composite sensor has better trimethylamine sensing performance than single-material sensor, such as shorter response/recovery time (27/33 s@1 ppm) and better selectivity. The frequency shift characteristics of the sensor were verified by the vector network analyzer and the figures of merit of the sensors were calculated. Experimental results show that WS2/PAA composite sensor based on two-dimensional (2D) transition metal sulfide provides a reliable way for the detection of trimethylamine. In addition, an app was designed to judge the freshness of seafood.