Electrobiosensing Of Glyceride Based On The Lipase Modified Electrodes

Electrobio-sensing technology, because of its high sensitivity, low cost, highautomation, miniaturization and other characteristics, is considered to be apromising analytical method. This method has a high selectivity to meet therequirements of complex sample analysis. Here, lipase was modified onto carbonpaste electrode （CPE）, screen-printed electrode （SPE） and glassy carbon electrode（GCE） via different immobilization strategies and methods. The modifiedelectrodes were used as the biosensor units for biorecognition and determination oftributyrin, dioleglyceride, and triolein. Several electrochemical methods wereapplied to characterize the solid-liquid interference reaction on the surfaces oflipase-modified sensors.In this thesis, the following work was done:1. Lipase and nano-NiO particles were modified into carbon paste electrode toprepare a tributyrin electrochemical sensor. Cyclic voltammetry （CV） anddifferential pulse voltammetry （DPV） were applied to characterize the voltammetricresponse of tributyrin on the modified electrode. The optimal conditions ofdetermination were carefully investigated. The linear detection dynamic range oftributyrin was0.5to50mg mL^-1.2. NiO-SPE was prepared through that Nano-NiO particples were deposited toscreen-printed electrode surface using the electrochemical oxidation technology.Lipase was embedded with chitosan on NiO-SPE to develop the new lipasebiosensor for detection of dioleglyceride. The electrochemical response revealedthat the lipase-NiO-SPE could be used to detect dioleglyceride in the range of2.5×10^-81.1×10^-3mg mL^-1with the detection limit of6.2×10^-9mg mL^-1. Therecovery of detection of real samples was92.8%to103.29%with great satisfactory.3. Lipase was attached to mesoporous silica zeolite on the glassy carbonelectrodes surface for fabrication of triolein biosensors. The linear detection rangewas from5×10^-4to5×10²mg mL^-1. By using electrochemical impedancespectroscopy, the interfacial reaction of the modified electrode was investigated,and the affinity of lipase modified electrode with triolein was verified. Theinterface of mesoporous silica zeolite could fix lipase effectively, and greatlybroaden the range of detection, or even to seven orders of magnitude. It could be verified that the lipase was attached effectively by mesoporous silica zeolitematerials through spectrophotometry.