Platinum Metals Rev., 1993, 37, (4), 219
Palladium in Cholesterol Sensors
Since the first discovery of the connection between high cholesterol levels in human serum and various diseases, such as heart disease and arteriosclerosis, there has been a need to develop a fast, accurate method to measure its level.
Now, a team at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, has developed a fast response cholesterol sensor based on an amperometric enzymatic technique, using a layer of palladium electrodeposited on a glassy carbon electrode (S. Dong. Q. Deng and G. Cheng, Anal. Chim. Acta, 1993, 279, (2), 235–240).
The dispersed palladium particles electro-catalysed the oxidation of hydrogen peroxide giving a large decrease in overvoltage. Cholesterol oxidase was immobilised on the electrode by cross-linking with glutaraldehyde. A layer of poly(o-phenylenediamine) film was electropolymerised on the enzyme layer thus preventing interference from uric acid and ascorbic acid and increasing the thermal stability of the sensor. The sensor had a response of less than 20 seconds in a concentration range 0.05–4.5 mmol/1. The sensor can be used for 200 assays without any decrease in activity.