The Application Of Ni Electrode On Analytical Method Of Electrochemiluminescence And Glucose Sensor

A flow-injection electrochemiluminescence (ECL) analysis of HCHO utilizing luminol in alkaline solution based on the electrocatalytic oxidation of HCHO was developed and a novel glucose sensor without enzyme has been prepared based on the electrochemical oxidation of glucose at a nickel electrode. The main results presented in this dissertation were summarized as follows:1. Based on the electrocatalytic oxidation of HCHO and its enhancement on ECL of luminol at a nickel electrode, a flow-injection electrochemiluminescence (ECL) analysis of HCHO utilizing luminol in alkaline solution was investigated. The mechanism of determination and quantificated method of HCHO has been discussed. The ECL emission intensity enhanced by the electrocatalytic oxidation of HCHO at potential of about 540 mV is proportional to the concentration of HCHO over the range of 3.36 to 60.6 ng/L, with a 2.80 × 10~11 mol/L detection limit(S/N=3) and a correlation coefficient of 0.998. The determination of HCHO could be performed in 4 min including sampling and washing, give a throughput of ca. 15 h~-1. The relative standard deviation (R.S.D.) is less than 6% (n=5) and the recovery is in the range of 98-107% for the determination of practical water samples. The result is contrast to that from spectrophotometry.2. A novel glucose sensor without enzyme has been prepared based on the electrochemical oxidation of glucose at a nickel electrode. The mechanism of electrochemical oxidation and response of sensor to glucose in human blood serum has been investigated. The Ni(III)/(II) species of nickel electrode surface acts as a oxidant for the oxidation of glucose in the alkaline solution, the glucose is quickly oxidized to glucolactone by the Ni(III) species resulting in the increase of current. The peak potential of electrochemical oxidation at 540 mV is employed as working potential of the sensor. The current response of sensor is proportional to concentrations of glucose, the detecting range is from 1.96×10~-5 to 1.80×10~-4 mol/L with a detection limit of 9.80×10~-6 mol/L. The response time of sensor is less than 60 seconds and dopamine, ascorbic acid as well as urea acid does not interfere with the determination of glucose. The sensor has been applied to determination of practical samples, the relative standard deviation (R.S.D.) is less than 4.3% (n=5) for the determination of glucose in humanblood serum and the result was consistent with that from the hexokinase method.