Investigation On Electrochemical Biosensors Based On Two Types Of Novel Nanomaterials

Due to small size effect, surface effect and other special performance for fabricating highly sensitive and selective sensing interface, nanomaterials have improved the analytical performance of electrochemical biosensor and have become the focus in the study of electroanalytical chemistry. In this thesis, the electrochemical biosensors were prepared based on nano-Porous CeO2to detect glucose and hydrogen peroxide, and the sodium nitrite electrochemical biosensor was assembled based on grapheme. The electrochemical method and other spectrum technology were adopted to study their performance. And new methods was established to detect glucose, H2O2and nitrite. This study provided a new idea to use nanocomposite in the electrochemical sensors, also expanded the application range of nanocomposite in electrochemical biosensor. This treatise included three chapters as follows:1. A review on the nanomaterial of the electrochemical biosensor presented with87references.2. A glucose electrochemical biosensor based on nano-Porous CeO2was fabricated. The direct electrochemistry and electrocatalysic performance of GOx was investigated. The results showed that the linearity range for determination is from1.0×10-6to6.0×10-4mol·L-1, with a detection limit of3.0×10-7mol·L-1(S/N=3) and a sensitivity of1.2×10-3μA-(mmol·L-1·cm2)-1.A novel hydrogen peroxide electrochemical biosensor based on the nano-Porous CeO2-Hb-CTAB was fabricated. And then direct electrochemical and electrocatalysis of the Hb was investigated.The results showed that the linearity range for determination of Hb is from5.0×10-7～2.0×10-3mol·L-1and a detection limit of1.7×10-7mol-L-1(S/N=3),with a sensitivity of2.8×10-2μA·(mmol·L-1·cm2)-1. The apparent Michaelis-Menten constant (KMapp) was calculated to be1.1×10-4mol·L-1.The studies above showed that nano-Porous CeO2, with good biological compatibility and high surface area, consequently could speed up the direct electron transfer of redox enzymes contemporary; The nano-Porous CeO2-CTAB composite membrane had excellent cooperativity. In conclusion, the present studies provided much more novel ways for the researchers to prepare electrochemical biosensor.3. A novel nitrite electrochemical biosensor based on the Nafion/Hb-GE-CTAB was fabricated. And the direct electrochemical and electrocatalysic performance of the Hb was investigated. The results showed that the linearity range for determination of Hb is from5.0×10-6to1.0×10-4mol·L-1(R=0.9994) and a detection limit of1.7×10-6mol·L-1(S/N=3), with a sensitivity of29μA·(mmol·L-1·cm2)-1. The Kyapp was calculated to be1.2×10-5mol·L-1.Accordingly, the GE-CTAB composite material provided a new method for sodium nitrate detection. The research showed that prepared GE-CTAB composite films had good biological compatibility, could speed up the direct electron transfer of Hb. This method has many advantages such as simplicity, settable, high sensitivity and chemical resistance.