A urea biosensor based on pH-sensitive Sm2TiO5 electrolyte-insulator-semiconductor.
A urea biosensor based on pH-sensitive Sm(2)TiO(5) electrolyte-insulator-semiconductor (EIS) has been described. We used X-ray diffraction, Auger electron spectroscopy, and atomic force microscopy to investigate the structural and morphological features of high-k Sm(2)TiO(5) sensing membranes that had been subjected to annealing at different temperatures. The EIS device incorporating a high-k Sm(2)TiO(5) sensing film that had been annealed at 900 degrees C exhibited good sensing characteristics, including a high sensitivity of 60.5 mV/pH (in solutions from pH 2 to 12), a small hysteresis voltage of 2.72 mV (in the pH loop 7-->4-->7-->10-->7), and a low drift rate of 1.15 mV h(-1) (in the buffer solution at pH 7). The Sm(2)TiO(5) EIS device also showed a high selective response towards H(+). This improvement can be attributed to the small number of crystal defects and the large surface roughness. In addition, the urea biosensor based on pH-sensitive EIS incorporating a Sm(2)TiO(5) sensing membrane annealed at 900 degrees C allowed the potentiometric analysis of urea, at concentrations ranging from 0.1 to 32 mM, with a sensitivity of 72.85 mV/purea.
Department of Electronics Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 333, Taiwan, ROC. tmpan@mail.cgu.edu.tw
Tung-Ming
TM
Pan
Ming-De
MD
Huang
Wan-Ying
WY
Lin
Min-Hsien
MH
Wu
D015374:Biosensing Techniques / Q000379:methods; D004573:Electrolytes / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D011199:Potentiometry; D012493:Samarium / Q000737:chemistry; D012666:Semiconductors / Q000295:instrumentation; D014025:Titanium / Q000737:chemistry; D014508:Urea / Q000032:analysis
D004573:Electrolytes; D012493:Samarium; D014508:Urea; D014025:Titanium