Doped SnO2 Nanomaterials for E-Nose Based Electrochemical Sensing of Biomarkers of Lung Cancer

Lung cancer detection includes detection of a pattern formed by multiple volatile organic compounds. An individual material has limited selectivity and hence requires tailoring to improve the selectivity and sensing properties. An electronic nose (e-nose) is a concept/device that can help in achieving selectivity and specificity for multiple volatile organic compounds at the same time by using an array of sensors. In this paper, Co and Ni doping in tin oxide was used to investigate as a sensor material for e-nose development. These were synthesized using a sol-gel method and were characterized for structural, morphological, and elemental assessment using X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy, which indicated the formation of the composite nanomaterial of SnO 2 . These synthesized materials were then used as a working electrode in the form of a screen-printed electrode to determine 1-propanol and isopropyl alcohol (IPA) sensing characteristics. Electrochemical characterization was done by cyclic voltammetry (CV) and electrochemical impedance spectroscopy. In the case of CV studies, well-defined and distinct redox peaks are observed at different potential values indicating the changes due to the dopants. Ni doping in SnO 2 shows the highest sensitivity of 2.99 μA/ppb for isopropyl alcohol and 3.11 for 1-propanol, within the detection range. Furthermore, Co-SnO 2 shows selectivity for IPA, while Ni-SnO 2 is selective to 1-propanol against all other volatile compounds analyzed.