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 (WS 2 ) and polyacrylic acid (PAA) nanocomposite coating was introduced for trimethylamine (TMA) gas molecule detection. WS 2 nanosheets were prepared by hydrothermal method and polyacrylic nanoparticles were prepared by solution polymerization . WS 2 , PAA and WS 2 /PAA sensors were prepared by spraying. The macrostate , microstructure and elementary composition of the nanomaterials were verified by characterization methods. The prepared WS 2 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 WS 2 /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 WS 2 /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.