Hydrophobic amino-functionalized graphene oxide nanocomposite for aldehydes detection in fish fillets

Some aldehydes (hexanal, octanal, and nonanal) are specific volatile organic compounds (VOCs) related to the quality of both freshwater fish and marine fish products, and these fish products are usually with relative high moisture. Herein, a quartz crystal microbalance (QCM) gas sensor modified with the hydrophobic amino-functionalized graphene oxide (AGO) nanocomposite for aldehydes detection was reported. The as-prepared materials were studied by X ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS). The sensor was exposed towards air streams containing aldehydes (hexanal, octanal, and nonanal in single, binary, and tertiary mixture) vapors with different concentrations under 80 % relative humidity (RH), and the sensor responded well towards aldehydes within 45 ppm. The sensor characteristics were validated by hydrophobicity, sensitivity, reversibility, selectivity and stability analyses. The sensing mechanism was proposed as (1) resistance to water vapor by hydrophobic silica nanoparticles; (2) hydrogen bonding interactions between the functional groups of AGO and aldehydes based on Gaussian calculations. This sensor was successfully applied to detect aldehydes in grass carp fish fillets and hairtail fillets. Solid phase micro extraction-gas chromatography mass spectrometer (SPME-GCMS) was used to detect aldehydes in the same fillets samples, and the results of the sensor and SPME-GCMS were high related with a correlation coefficient of 0.98.