VOC Gas Sensors Fabricated with Graphene Oxide Composites for Food Safety and Quality

For food market, off-odors or flavors have become more than a quality issue with the increased awareness of food safety problems. This awareness to solve the safety problems, off-odor detection in foods, packaging materials, and their interactions involving scalping or other flavor system modification have been attracted. One of suggested methods is to use an electronic nose consisting of a gas sensor array to detect the volatile organic compounds (VOCs), released from foods as a byproduct of everyday physiological processes. Monitoring of the specific VOCs by a gas sensor can provide the information on both crop and field conditions. The array structure of gas sensors can enhance selectivity for in-situ detection [1, 2].

In this study, an array of sensors is investigated by employing graphene oxide and nanostructured metal oxide based on SnO₂. Their composite films on a series of electrodes are prepared to create a high density of sensing array in a small size chip. A composition gradient sensing layers can produce  unique gas response patterns. Figure 1 shows surface morphology of compositionally gradient tin oxides (1:6 ratio of GO to SnO₂) and structure property confirmed by XRD result. The results on the growth of nanostructured films using solution process and vacuum process are presented. Figure 2 also shows sensing properties of the composites to formaldehyde gas at room temperature. The combinatorial structure enhances the sensing properties of devices in terms of sensitivity, selectivity and response rate. Additionally, such a sensor can meet the proposed idea, in-situ detection, and also the requirements for low-cost and high-volume production as well as high gas analytical performance.

This research was partially supported by a grant from a Strategic Research Project (2013-0132) funded by the Korea Institute of Construction Technology, and Auburn University IGP.

[1]     A. D. Wilson and M. Baietto. Sensors. 2009, 9:5099-5148.

[2]     K. Arshak, E. Moore, G. M. Lyons, J. Harris, and S. Clifford. Sensor Review. 2004, 24(2):181-198.