Synthesis and characterization of vanadium oxide/hexadecylamine membrane and its application as pH-EGFET sensor

Vanadium oxide/hexadecylamine (V2O5/HDA) sensing membrane was deposited on the glassy carbon substrate and used as the sensing layer of the extended gate H+-ion sensitive field effect transistor (EGFET) device. The structural and morphological features of V2O5/HDA were studied by X-ray diffraction, Fourier transformed-infrared spectroscopy and Scanning electronic microscopy images; and the electrochemical behavior was analyzed by cyclic voltammogram. V2O5/HDA presents a lamellar structure as well as several rod formations. The material stabilizes electrochemically after several cycles and leads to reproducibility of Li+ ion insertion/de-insertion into the vanadium oxide structure. The material was investigated as a pH sensor in the pH range 2-12 and presented a sensitivity of 38.1 mV/pH. The sensitive membrane structure is simple to fabricate and the measurement is fast for application as a disposable sensor.