Formalin Adulteration Detection in Food Using E-nose based on Nanocomposite Gas Sensors

The aim of this work is to develop an electronic nose (e-nose) system for the detection of toxic formaldehyde as a response to illegal addition of formalin into foods in the markets and food processing industries. In this work, nanocomposites of 0-phenylenediamine (OPD) with different functionalized single-walled carbon nanotubes (f-SWCNTs) were used as gas sensing materials. The gas sensors have been tested to perceive the individual response to different volatile organic compounds (VOCs). Since they showed the highest response to formaldehyde which is the main component in formalin solution, the gas sensor array is appropriate for the detection of food contamination due to formalin. By setting up two conditions, namely non-treatment and formalin treatment to raw chicken, shrimp and tofu, as well as shrimps with different concentrations of formalin treatment, the odor associated with those conditions was investigated by e-nose. Discrimination and analysis of non-treatment (natural) and formalin contaminated samples were analyzed by the principal component analysis (PCA). Our findings support the integration of nanocomposite gas sensors into e-nose as an advantageous tool for food safety applications.